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Select this Article		Is the Knowledge Management System Truly Cost Effective? A Case Study of KM‐Enabled Engineering Problem Solving Wen‐Der Yu, Ting‐Chun Lin, Shen‐Jung Liu, and Pei‐Lun Chang Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000604 Posted ahead of print 16 May 2012 Full Text: \| Download PDF
	+ -	Show Abstract Managers of construction organizations were long faced with an essential question: “Is a knowledge management system (KMS) truly cost effective?” Very few empirical studies were done to measure the effective benefits of implementing knowledge management initiatives. Lack of quantitative measurement model, difficulty of differentiating Knowledge Management (KM) vs. non‐KM activities, difficulty of evaluating resultant KM activity values, and unwillingness of organizations to reveal insights in order to shield such from their competitors are major reasons for the absence of abovementioned empirical reports. This case study reveals a five‐year comprehensive benefit survey on the implementation of a specialized KMS, KM‐enabled problem‐solver, at a major engineering consulting firm. Totally 868 emergency problem‐solving cases recorded in the KMS were analyzed. Three most concerned benefit indexes, time, cost, and man‐hour, selected by the KM managers were measured. Results show timeliness to be the most remarkable tangible benefit. Both man‐hour and cost benefits were found to be negative. Even though, qualitative benefits are identified and addressed via focus‐group meetings with the KM managers. The research found the KM approach not suited to solving all types of engineering problems. Strategies should be taken to facilitate engineering problem solving, including the development of a more proactive approach.

Select this Article		Assessment of Residential Defects at Post‐Handover Nuria Forcada, Marcel Macarulla, and Peter E.D. Love Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000603 Posted ahead of print 16 May 2012 Full Text: \| Download PDF
	+ -	Show Abstract In Spain, the Ley de Ordenación de la Edificación (Building Regulation Act) has established compulsory warranties to ensure that buildings meet basic requirements with regard to functionality, general safety and structure, fire‐proofing, and use and habitability. Despite this regulatory body's requirements, defects in newly built dwellings remain a pervasive problem, which has resulted in a plethora of complaints to the Instituto Nacional del Consumo (National Institute for Consumers Protection), which deals with consumer protection in Spain. In this paper, a total of 2351 post handover defects derived from four Spanish builders and seven residential developments are classified according to their location, subcontract, and element. The research reveals that the most common defects identified at handover by customers were incomplete tile grouting and incorrect fixtures and fittings in toilets. In addition, failure to apply second coats of paint to walls was deemed a problematic issue. Typical surface/appearance defects were found to include floor or wall unevenness, stains, mess, small cracks and marks mainly caused by lack of protection. In areas where fixture and fittings and finishes were of a similar nature, such as the kitchen and bathroom, defect types also arose. Determining the location, subcontract, and element where defects occur in residential buildings can provide invaluable knowledge about areas where builders are likely to make errors, mistakes or take deliberate short‐cuts during construction. Thus, emphasis on quality control and supervision of subcontract trades, especially in the areas identified, and during the final stages of residential construction are critical to ensure defects are reduced.

Select this Article		Computing a Displacement Distance Equivalent to Optimize Plans for Post‐Disaster Temporary Housing Projects Omar El‐Anwar, A. M. ASCE and Lei Chen Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000601 Posted ahead of print 4 May 2012 Full Text: \| Download PDF
	+ -	Show Abstract Temporary housing is a critical period for the social, economic, and psychological recovery of displaced families following disasters. Temporary housing locations define the displacement distance between families and their essential needs. The objective of this paper is to develop a novel methodology to capture the specific proximity needs and preferences of displaced families. This paper proposes “displacement distance equivalent” as an objective metric to evaluate the performance of temporary housing locations in meeting the needs of displaced families. Moreover, this paper describes the development of an integer programming optimization model capable of optimizing temporary housing assignments to minimize total displacement distance equivalent while meeting budget constraints. The main contribution of this paper to the body of knowledge is in transforming the purpose of temporary housing programs from offering general accommodation to providing customized housing solutions tailored to the individual proximity needs of each household using the proposed displacement metric. In addition, the proposed optimization model enables decision makers to set budget constraints to ensure the economic feasibility of identified temporary housing solutions. The proposed model should prove useful to emergency planners in selecting the optimal locations for the construction of new temporary housing projects as well as the optimal locations of lease/rental units. An application example is presented to demonstrate the capabilities of the developed model and identify research opportunities both in the theoretical formulation and computational efficiency of temporary housing decision support.

Select this Article		Applying Risk Management Workshop for a Public Construction Project: A Case Study Cheng Siew Goh and Hamzah Abdul‐Rahman Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000599 Posted ahead of print 4 May 2012 Full Text: \| Download PDF
	+ -	Show Abstract The selection of proper risk management tools and techniques is critical for better decision‐making. As very few studies scrutinize the use of workshop as a means of risk management approach, this paper aims to explore how a risk management workshop can be effectively used in managing project risks by studying a risk management workshop that was conducted in a public project. An in‐depth case study approach was adopted to identify the benefits and challenges of this method of risk management. The subsequent performance of the public organization in managing risks was examined by evaluating its functional risk management implementation. In addition to furthering an organization's understanding of major project risks, a risk management workshop also provides opportunities for teambuilding. However, a breakdown in the risk communication which eventually resulted in a poor risk management implementation was uncovered in the project implementation. Continued efforts to improve risk management implementation are needed to overcome the shortcomings associated with the current practices.

Select this Article		Critical Success Factors for Key Project Players and Objectives: Case Study of Singapore Bon‐Gang Hwang and E‐Sin Janicia Lim Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000597 Posted ahead of print 3 May 2012 Full Text: \| Download PDF
	+ -	Show Abstract Critical Success Factors (CSFs) are used to support and measure the success of a strategic and tactical approach to project execution with the intent of ensuring the success of the project delivery system and to support the appropriate allocation of limited resources. This study aims to identify CSFs in terms of the different project players and their objectives in the context of the Singapore construction industry. To achieve the objective, 32 CSFs were first identified and classified into 4 major categories, specifically, (1) project characteristics, (2) contractual arrangements, (3) project participants, and (4) interactive processes. Then the Analytic Hierarchy Process (AHP) method was employed to establish a hierarchical model of their relative importance. To facilitate systematic analysis on their importance, 12 experts with at least 10 years of industry experience were surveyed and then through the use of the Expert Choice software, the CSFs addressing budget performance, schedule performance, quality performance, and overall project success were identified. The results of this study may serve as a tool for the construction industry to assess rapidly the possibility of successful achievement of project objectives.

Select this Article		Stabilizing Production Flow of Interior and Finishing Works with Re‐Entrant Flow in Building Construction Irina Brodetskaia, Rafael Sacks, and Aviad Shapira, F. ASCE Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000595 Posted ahead of print 3 May 2012 Full Text: \| Download PDF
	+ -	Show Abstract Interior and finishing activities in building construction exhibit high degrees of variation as a result of uncertainty in supply chains, variations in work quantities, client changes and lack of predictability of the production capacity of subcontracting trades. Decisions must constantly be made concerning effective utilization of available resources. Re‐entrant workflow patterns, where a trade crew returns multiple times to the same space, make production control particularly difficult. We present a method for pull flow control at the operational level through real‐time prioritization of pending work‐packages and daily regulation of crew assignments and trades' production capacities. Application of various heuristics was evaluated using discrete‐event simulation of a representative construction project. The experimental results emphasize the importance of dynamic control of allocation of production resources to those mature activities that ensure subsequent (downstream) flow. The most successful policy was to use the second re‐entrant activity as a bottleneck, and to regulate the capacity of the trade with re‐entrant flows to ensure sufficient feeding of new work to successive crews.

Select this Article		Resource Sharing‐Based Multi‐Objective Multistage Construction Equipment Allocation under Fuzzy Environment Jiuping Xu, M. ASCE, Jun Meng, Ziqiang Zeng, Shiyong Wu, and Manbin Shen Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000593 Posted ahead of print 3 May 2012 Full Text: \| Download PDF
	+ -	Show Abstract This paper presents a resource sharing‐based construction equipment allocation problem with multiple stages under a fuzzy environment. A multi‐objective multistage decision making model is established in which the equipment failure rate is regarded as a fuzzy variable. In contrast to traditional assignment problems, the principle of resource sharing modes including space and time sharing is considered based on the project practice. In addition, a dynamic programming‐based genetic algorithm is developed to find feasible solutions and a dynamic programming‐based initialization, crossover and mutation are designed to avoid infeasible solutions. Finally, the Jinping‐I Hydropower Project is used as a practical example to demonstrate the practicality and efficiency of the model. The results analysis and comparisons are presented to highlight the performance of the optimization method, which is proved to be very effective and efficient as compared to the standard genetic algorithm.

Select this Article		Development and Interpretation of the Security Rating Index Jonathan R. Sylvie, M. ASCE, Stephen R. Thomas, M. ASCE, Sang‐Hoon Lee, M. ASCE, Robert E. Chapman, and Ryan T. Smith Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000591 Posted ahead of print 2 May 2012 Full Text: \| Download PDF
	+ -	Show Abstract This paper documents the second phase of a three‐phase research effort to develop and deploy best practices for project security on industrial construction projects. Specifically, it details the development and interpretation, and initial validation of the Security Rating Index, which provides a means of quantitatively assessing the level of implementation of security practices for a project. The Security Rating Index must be used in the context of threat and consequence levels. The threat level quantifies the intention and capability of an adversary to undertake detrimental actions while the consequence level quantifies potential impacts of a security breach over the facility life cycle. This approach allows comparisons to be made between projects with similar security considerations. The Security Rating Index is the first tool to integrate and quantify risk, consequence, and security best practice implementation. It can also be used as a checklist to integrate the appropriate security measures in the early phases of project planning. Once sufficient data are available, the Security Rating Index will provide a means by which companies can gauge the level of security integration of their own projects against similar projects within the industry.

Select this Article		Performance Measurement to Aid Decision Making in the Budgeting Process for Apartment Building Construction: A Case Study Using MCDA‐C Rogério Cabral de Azevedo, Rogério Tadeu de Oliveira Lacerda, Leonardo Ensslin, Antônio Edésio Jungles, and Sandra Rolim Ensslin Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000587 Posted ahead of print 2 May 2012 Full Text: \| Download PDF
	+ -	Show Abstract The construction environment has become increasingly complex and dynamic due to increased competitiveness and new technological and market practices, all of which require fast, accurate answers from decision‐makers. In this context, performance indicators have been used as the basis for decision support by various sectors of the construction industry. The Brazilian apartment building construction sector is the industry sector with the highest individual contribution (based in the gross domestic product) to the construction process, mostly composed of small and medium‐sized businesses. In the residential construction sector, most decisions are made in very unstructured and intuitive ways, and the initial budgeting process is one of the most critical phases due to the high level of uncertainty in the early stages of a project. In addition, most methods for measuring performance based on indicators have been developed without regard to the preferences and values of the persons who have the responsibility for improving the unique environment in which budgeting problems occur. Using the multicriteria decision aid — constructivist methodology (MCDA—C) a framework for budget performance evaluation for apartment buildings projects was developed, wherein the characteristics of the context evaluated have been identified, organized, measured, and integrated according to the decision maker's values and preferences. The framework enables decision‐makers to understand the current situation more accurately with respect to each criterion evaluated and to the whole. This would allow planning actions to improve the budget process to ensure better quality and accuracy, determine the impact of these actions on the overall assessment of the context and prioritize actions according to their goals. Performance evaluation models built with the MCDA‐C have the capacity to generate actors' knowledge concerning the context they intend to improve and can be used as a tool to produce competitive advantages.

Select this Article		A Generic Model for Measuring Benefits of BIM as a Learning Tool in Construction Tasks Weisheng Lu, Yi Peng, Qiping Shen, and Heng Li Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000585 Posted ahead of print 2 May 2012 Full Text: \| Download PDF
	+ -	Show Abstract Over the past years, people's understanding towards Building Information Modeling (BIM) in the architecture, engineering, and construction (AEC) industry has improved significantly. BIM can be diversely recognized as a virtual design and construction environment, a communication vehicle among stakeholders, a lifelong information model, or an education platform that can be used in universities or colleges. BIM can also be used as a learning tool that can aid project teams in familiarizing themselves with a construction task, prior to commencement of the task on site. Yet, little effort has been made to measure the benefits of this kind. The aim of this research is to empirically measure the benefits of BIM as a learning tool in real‐life construction tasks. The learning curves of two situations: construction tasks with and construction tasks without BIM are identified by following a series of analytical processes. The two learning curves are compared and the learning effects contributed by BIM are modeled as L_effBIM. By inputting their own data, practitioners may use this generic model to measure learning effects contributed by BIM in their own projects. The model can be used to convince potential BIM users by showing empirical evidence of BIM's benefits. It is also hoped that the model can join the concerted efforts to promote BIM's value in the AEC industry.

Select this Article		A Model for Enhancing Integrated Identification, Assessment and Operational Control of On‐Site Environmental Impacts and Health and Safety Risks in Construction Firms Marta Gangolells and Miquel Casals Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000579 Posted ahead of print 30 April 2012 Full Text: \| Download PDF
	+ -	Show Abstract Certifiable management system standards apply similar management techniques and principles, but each system still tends to have a separate structure in construction companies. Research and practice have demonstrated that management tasks may be duplicated when standards are implemented in parallel. Consequently, integrated management systems are strongly advocated. However, existing literature demonstrates that the integration of planning and control instruments involves a high level of uncertainty. We present an innovative model to enhance the integration of environmental and health and safety management systems in construction companies, focusing on the sub‐systems for identifying, assessing and operationally controlling environmental aspects and health and safety hazards and using risk as an integrating factor. The findings of this study have direct implications for both designers and contractors as the model helps to explicitly consider on‐site environmental impacts and construction worker safety during the design process and offers on‐site guidance to eliminate the remaining impacts and risks or reduce them to an acceptable level. A case study is reported to illustrate the practical use of the proposed model and its benefits.

Select this Article		Dynamic Feasibility Analysis of the Housing Supply Strategies in a Recession: The Case of the Korean Housing Market Sungjoo Hwang, Moonseo Park, M. ASCE, Hyun‐Soo Lee, M. ASCE, SangHyun Lee, M. ASCE, and Hyunsoo Kim Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000577 Posted ahead of print 30 April 2012 Full Text: \| Download PDF
	+ -	Show Abstract Establishing housing supply strategies in a stagnant housing market is a significant issue due to two contradictory and concurrent problems: first is the long‐cherished desire to supply low‐cost housing for low‐ and middle‐income families; the second is the problem of high vacancy levels due to low‐level sales rates. Governments have been continuously implementing various supply policies intended to distribute houses evenly and to keep supply and demand in balance. However, it is difficult to satisfy consumers, owners, and suppliers due to conflicting needs and requirements. This paper therefore applies a system dynamics methodology and offers an integrated model that encompasses the for‐profit behavior of each market participant, analyzes supply policies, and suggests appropriate and effective policies. Utilizing the case of the Korean housing market, the proposed model simulates future trends in house prices, balances between supply and demand, construction companies' earnings, and vacancy rates when various housing supply scenarios are applied. With extensive studies with the results from the simulation model, we recommend using private construction companies to stabilize housing distribution rates and the private supply system, as well as to ensure a balance between supply and demand.

Select this Article		Determining the Probability of Project Cost Overruns Peter E. D. Love, Xiangyu Wang, Chun‐Pong Sing, and Robert L. K. Tiong Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000575 Posted ahead of print 28 April 2012 Full Text: \| Download PDF
	+ -	Show Abstract The budget at the decision to build has often been used as the reference point for determining the project's cost overrun. As a result, the calculation of a project's cost overrun can be inflated. In this paper, the statistical characteristics of cost overruns experienced from contract award in 276 Australian construction and engineering projects were analyzed. The skewness and kurtosis values of the cost overruns are computed to determine if the empirical distribution of the data follows a Normal distribution. The empirical distributions for the cost overruns are found to be non‐Gaussian. Theoretical probability distributions are fitted to the cost overrun data. The Kolmogorov‐Smirnov, Anderson‐Darling and Chi‐Squared non‐parametric tests are used to determine the ‘Goodness of Fit’ of the selected probability distributions. A 3‐Parameter Frechet probability function is found to describe the behavior of cost overruns and provide the best overall distribution fit. The Frechet distribution is then used to calculate the probability of a cost overrun being experienced. The statistical characteristics of contract size and cost overruns were also analyzed. The Cauchy (<A$1m), Wakeby (A$1–10m, <A$101m) and 4‐Parameter Burr (A$11–50m) were found to provide the best distribution fits and used to calculate cost overrun probabilities by contract size. Ascertaining the best fit probability distribution from an empirical distribution at contract award can produce realistic probabilities of cost overruns, which should then be incorporated into a construction cost contingency.

Select this Article		Identifying and Categorizing the Sources of Uncertainty in Construction Supply Chains Jonathan Gosling, Mohamed Naim, and Denis Towill Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000574 Posted ahead of print 19 April 2012 Full Text: \| Download PDF
	+ -	Show Abstract Uncertainty affecting operations has long been recognized by researchers as a major obstacle to the delivery of customer value in supply chains. Whilst it has been acknowledged that different types of supply chain have different uncertainty profiles, there is little academic literature addressing the particular uncertainties relating to engineer‐to‐order (ETO) supply chains, where each product is designed for the needs of a specific customer. The key research question addressed in this paper is ‘How can the substantive sources of project uncertainty in construction supply chains be identified and categorized?’ A three‐phase framework for the identification and categorization of uncertainty is proposed. The empirical investigation reported in this paper demonstrates how the framework may be applied to a group of ETO projects. Using multiple data collection methods, including site visits, interviews and industry workshops, the uncertainties in five projects are identified and categorized using the framework to demonstrate its application. The framework thereby established is generalized to cover a range of construction projects.

Select this Article		Factors That Affect Transaction Costs in Construction Projects Huimin Li, David Arditi, and Zhuofu Wang Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000573 Posted ahead of print 19 April 2012 Full Text: \| Download PDF
	+ -	Show Abstract The actual cost of a construction project is composed of not only production costs, but also transaction costs. Transaction costs include but are not limited to the costs of preparing the bidding package, estimating, drawing up a contract, administering the contract, and dealing with any deviations from contract conditions. Transaction costs constitute an important part of the construction owner's budget. However, understanding transaction costs is difficult because of the inconsistency and the ambiguity in defining transaction costs in the literature. The objective of this study is to identify ways to minimize the transaction costs borne by the construction owner. A structural equation model is tested on data collected by means of a survey administered to construction owners. The findings indicate that the transaction costs borne by the owner can be minimized if the owner minimizes the uncertainties inherent in the transaction environment by (1) making sure the engineering design is as complete as possible before bids are sought from contractors, (2) exploring the possibility of adopting integrated project delivery methods that would allow the owner to engage the services of a contractor early in the design phase, (3) agreeing to share some of the risks with the contractors, (4) understanding well the behavior of contractors, and (5) paying close attention to project management efficiency.

Select this Article		Performance‐Cost Analysis of Stabilized Undercut Subgrades Benjamin Cote, Brent Robinson, P.E., M. A. Gabr, Ph.D., P.E., and Roy H. Borden, Ph.D., P.E. Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000572 Posted ahead of print 19 April 2012 Full Text: \| Download PDF
	+ -	Show Abstract An approach for comparatively evaluating the performance‐cost of undercut subgrade stabilization measures is presented. The performance‐cost analysis coupled results from laboratory cyclic load testing with material prices and estimated cost factors for stabilization alternatives. The study utilized data from twenty‐two simulated undercut sections with different stabilization configurations over a soft subgrade with a California Bearing Ratio (CBR) of approximately 2.0%. The computed cost factors are normalized with respect to the rut‐depth magnitudeand the subgrade strength. The results showed that sections with lime stabilized subgrade (LSS) were the most economical over initial and post‐rut repair cycles. Unreinforced aggregate based course (ABC) sections between 14 and 20 inches in thickness were economical during initial cycles. Sections with geosynthetic‐reinforcement showed that once enough rut depth is induced to mobilize the strength of the reinforcement, economical performance was comparable to other stabilization measures excluding LSS. When the ABC layer was thicker (between 18 and 20 inches), differences in the reinforcement type were less significant. Tests with 36 inch select fill overlaid by three inch ABC stabilization had a high unit cost, but were moderately economical. This study shows the advantage of including performance aspects (such as rut depth and subgrade strength) when considering the overall cost of stabilization.

Select this Article		Modification of Advanced Programmatic Risk Analysis and Management Model for the Whole Project Life Cycle's Risks Mehran Zeynalian, Bambang Trigunarsyah, and H. R. Ronagh Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000571 Posted ahead of print 13 April 2012 Full Text: \| Download PDF
	+ -	Show Abstract Advanced Programmatic Risk Analysis and Management Model (APRAM) is one of the recently developed methods which can be used for risk analysis and management purposes considering schedule, cost and quality risks simultaneously. However, this model considers those failure risks that occur only over the design and construction phases of a project's life cycle. While it can be sufficient for some projects, for which the required cost during the operating life is much less than the budget required over the construction period, it should be modified in relation to infrastructure projects as the associated costs during the operating life cycle are significant. In this paper, we propose modified APRAM model, which can consider potential risks that might occur over the entire life cycle of the project, including technical and managerial failure risks. Therefore, the modified model can be used as an efficient decision‐support tool for construction managers in housing industry where various alternatives might be available, technically. The modified method is demonstrated using a real building project, and this demonstration shows that it can be employed efficiently by construction managers. Delphi method was applied in order to figure out the failure events and their associated probabilities. The results show that although the initial cost of cold formed steel structural system is higher than conventional construction system, the former's failure cost is much lower than the latters'.

Select this Article		Time and Cost‐Optimized Decision Support Model for Fast‐Track Projects Kyuman Cho and Makarand Hastak Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000570 Posted ahead of print 10 April 2012 Full Text: \| Download PDF
	+ -	Show Abstract The fast‐track method is one of the most recognized methodologies for reducing construction project schedules. However, due to the lack of definitive research to date pertaining to the effects of fast‐track application in terms of time and cost, it has been difficult for project owners to determine its correct application. This paper presents the Time And Cost opTImized deCision Support (TACTICS) model, and it was developed based on the fast‐track methodology and genetic algorithms (GA). TACTICS was applied to two case studies, and the results indicated that the fast‐track method could be expected to deliver more efficient projects, compared to using the traditional method. In particular, (i) the average reduction in project duration by applying the fast‐track method was 40.48% (Case I) and 18.59% (Case II) compared to using the traditional method, and (ii) the average project costs were reduced by as much as 0.39% (Case I) and 4.48% (Case II). Consequently, TACTICS could be expected to help in making a decision regarding the fast‐track application and further contribute to the project scheduling expertise in the CEM body of knowledge.

Select this Article		Integrated LOB and CPM Method for Scheduling Repetitive Projects Mohammad A. Ammar Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000569 Posted ahead of print 10 April 2012 Full Text: \| Download PDF
	+ -	Show Abstract Repetitive projects require schedules that ensure the uninterrupted usage of resources from a unit to similar units in a repetitive activity while maintaining logical dependency constraints. Critical Path Method (CPM) is the widely used and accepted planning and scheduling method for traditional (non‐repetitive) projects. However, CPM does not suit the planning and scheduling needs of repetitive projects. Consequently, resource‐driven techniques (such as Line‐Of‐Balance; LOB) have been used to schedule repetitive projects which insure work continuity. LOB is mainly a graphical technique which lacks the analytical qualities of CPM scheduling. A need for an analytical technique fulfilling characteristics of repetitive projects has been reported in the literature. Few attempts have been made to combine the benefits of CPM and LOB techniques in planning and scheduling of repetitive projects. In this paper, an integrated CPM and LOB model has been developed to schedule repetitive projects in an easy non‐graphical way considering both logic dependency and resource continuity constraints. Overlapping activities of a single typical unit are used to model duration and logical relationships of repetitive activities. The proposed model consists basically of four steps. In the first step, basic LOB calculations are performed to insure resource continuity. Activity duration along all repetitive units is calculated in the second step. In the third step, overlapping activities are used to model logical relationships between consecutive activities. Then, CPM time analysis is performed to specify activities' timings and floats and project completion time. An example application is finally presented to illustrate the implementation and features of the proposed model.

Select this Article		Communication Makes a Corporate Code of Ethics Effective: Learnt from Hong Kong Experience Christabel M. F. Ho, Ph.D. Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000568 Posted ahead of print 2 April 2012 Full Text: \| Download PDF
	+ -	Show Abstract Ten years after the start of a major business ethics campaign spearheaded by the Hong Kong Ethics Development Centre and the Hong Kong Housing Department in 2001, the relationships were examined between different methods of communicating the corporate code of ethics within a particular organization and the attitudes of the employees towards that code. An attitude survey was employed to identify the relationships. The research findings show that some communication methods are more effective in influencing employee attitudes than others. Use of informal communication channels together with formal sources of information are generally more highly valued by employees. Employees consider that they receive less ethics‐related information than they actually need irrespective of whether the channel of communication is formal or informal. The findings of this study confirm that a corporate code of ethics must be communicated in the right way if it is to influence the ethical behavior of employees.

Select this Article		Analysis of Construction Equipment Safety in Temporary Work at Height J. C. Rubio‐Romero, M. C. Rubio, and C. García‐Hernández Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000567 Posted ahead of print 31 March 2012 Full Text: \| Download PDF
	+ -	Show Abstract Temporary work at height is one of the main causes of construction accidents that result in serious injuries and fatalities. Many of these accidents occur because of falls from scaffolding and work platforms. In Europe, scaffolding, as equipment for temporary work at height is regulated by the Directive on Work Equipment 89/655/EEC, afterwards superseded by Directives 95/63/EC and 2001/45/EC. A directive is a legislative act of the European Union, which requires member states to achieve a particular result without dictating the means of achieving that result. All of these directives belong to the category of European Health and Safety at Work Directives. In this sense, the European Standard HD‐1000 is of great interest since it facilitates compliance with the requirements of Directive 2001/45/EC regarding temporary work at height. This article presents the results of a research study that was carried out in Spain between March 2003 and 2004 in which 146 construction sites were inspected with a view to examining the scaffolding surface at each one. The building sites whose scaffolding complied with European Standard HD‐1000 were compared to those with older (non‐standard) scaffolding. Both types were qualitatively evaluated to ascertain their safety levels. The findings obtained in this research study show that the standardization of scaffolding equipment had direct and positive impact on work safety conditions at construction sites. Consequently, fomenting the standardization of scaffolding equipment in the construction industry can contribute to improving work safety conditions as has occurred in Spain. The methodology in our study can also be applied in other countries to evaluate their regulations or codes regarding personal protective equipment.

Select this Article		Social Sustainability Considerations during Planning and Design: A Framework of Processes for Construction Projects Rodolfo Valdes‐Vasquez, Ph.D., Aff. M. ASCE and Leidy E. Klotz, Ph.D., M. ASCE Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000566 Posted ahead of print 30 March 2012 Full Text: \| Download PDF
	+ -	Show Abstract This research identifies 50 processes and categorizes them into a framework for integrating and evaluating social considerations in construction projects. These processes focus on the planning and design phases because they offer the greatest potential for influencing project performance. The concept mapping research method was applied to develop this framework based on input from 25 experts in academia, industry and government. Multidimensional scaling and hierarchical cluster analyses were used to organize the experts' input into six categories defining social sustainability in construction projects: Stakeholder Engagement, User Considerations, Team Formation, Management Considerations, Impact Assessment, and Place Context. While previous research has recognized social sustainability as a series of processes, this study is the first to integrate them into a comprehensive framework. Practitioners can benefit from this framework, which will enhance existing sustainability assessment methods and help address the challenge of developing truly sustainable projects. This framework also provides academics with a tool for introducing students to social sustainability in construction projects. Future research could use this framework as a baseline, developing metrics using the processes included in the framework.

Select this Article		Comparison of Image‐ and Time‐of‐Flight‐Based Technologies for 3D Reconstruction of Infrastructure Fei Dai, S. M. ASCE, Abbas Rashidi, S. M. ASCE, Ioannis Brilakis, A. M. ASCE, and Patricio Vela Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000565 Posted ahead of print 30 March 2012 Full Text: \| Download PDF
	+ -	Show Abstract As‐built spatial data is useful in many construction‐related applications, such as quality control and progress monitoring. These data can be collected using a number of imaging and time‐of‐flight‐based (e.g., laser scanning) sensor methods. Each application will demand a particular level of data accuracy and quality, yet little information is available to help engineers choose the most cost‐effective approach. This paper presents an analytical and quantitative comparison of photogrammetric, videogrammetric, and time‐of‐flight‐based methods. This comparison is done with respect to accuracy, quality, time efficiency, and cost. To this end, representative image‐based 3D reconstruction software and commercially available hardware (two cameras, and a time‐of‐flight‐based laser scanner), are evaluated. Spatial data of typical infrastructure (two bridges and a building) is collected under different settings. The experimental parameters include camera type, resolution, and shooting distance for the imaging sensors. By comparing these data with the ground truth collected by a total station, it reveals video/photogrammetry can produce results of moderate accuracy and quality, but at a much lower cost as compared to laser scanning. The obtained information is useful to help engineers make cost‐effective decisions and help researchers better understand the performance impact of these settings for the sensor technologies.

Select this Article		Sino‐American Opinions and Perceptions of Counterfeiting in the Construction Supply Chain R. Edward Minchin, Jr., Shuai Cui, Russell C. Walters, Raymond Issa, and Jiayi Pan Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000564 Posted ahead of print 30 March 2012 Full Text: \| Download PDF
	+ -	Show Abstract Incidents of counterfeit products harming humans have been widely reported in the western press. Counterfeit handbags and jeans are easily obtainable at several well‐known locations around the world, including many in the U.S. The construction industry is not immune from the world‐wide problems of counterfeiting. Research reported on by this paper identified the center of the problem as the People's Republic of China (PRC). In addition, the research concluded that there are significant differences in the attitudes toward counterfeiting exhibited by people living and working in North America and those living and working in the PRC. The research, based on almost 200 interviews, revealed that most Chinese manufacturers believe that “close enough is good enough” and many Chinese have a hard time understanding why that is not acceptable to the U.S. market. Of course, many U.S. and Canadian companies have had great success procuring quality material and products from China, but most have achieved this success through extensive education and training of the Chinese manufacturer and supplier, and excruciating diligence in the oversight of their entire supply chain.

Select this Article		Protocol for Profitability Analysis Using Internal Entities in Organizational Structure of Construction Companies Ziad Tamer, Yoojung Yoon, and Makarand Hastak, M. ASCE Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000563 Posted ahead of print 30 March 2012 Full Text: \| Download PDF
	+ -	Show Abstract Construction companies bid on projects and expect to obtain a profit by implementing awarded projects. As a profit generating entity, the construction companies are composed of cost and profit centers. The cost centers within the organization provide services required to fulfill the activities of the profit centers. The profit centers create billable work that is reimbursed by the owners of the projects. However, construction companies have had difficulty in winning new construction projects due to high competition, economic recession, etc. Also, many construction companies are not obtaining the profits they expect from the awarded projects. Therefore, a protocol to analyze profitability should be developed in order to understand the gaps between actual and estimated profit as well as the origins of loss of profit on construction projects. The purpose of this paper is to present a protocol for profitability analysis for the construction companies. The construction companies can utilize the protocol to identify relationships among entities of the cost and profit centers so that they can: 1) recognize the changes in profit margins of projects, 2) improve their overall profitability by eliminating problems from the relationships for the prospective projects, and 3) be selective of more profitable projects in the bidding phase. This paper applies the developed protocol to three construction projects executed by a mid‐size construction company with a functional organizational structure.

Select this Article		Subcontracting Practices in the Construction Industry of Pakistan Rafiq M. Choudhry, Jimmie W. Hinze, and Muhammad Arshad Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000562 Posted ahead of print 30 March 2012 Full Text: \| Download PDF
	+ -	Show Abstract Subcontracting on construction projects is a common and well‐established practice. Contractors enlist the services of subcontractors to achieve certain objectives, including obtaining cost reductions, securing access to specialized services, and risk sharing. Nonetheless, subcontracting on a project can introduce certain associated problems which can affect construction management and construction quality. This research explored exclusively the subcontracting practices in the construction industry of Pakistan, identified the main problem areas, examined the overall satisfaction with the quality of service provided by subcontractors, and focused on ways to improve the quality of construction affected by subcontracting. A questionnaire survey was conducted to investigate the extent and involvement of construction firms in subcontracting, reasons for subcontracting, and the selection criteria of subcontractors. Additionally, interviews were conducted with researchers, professionals and experts of the industry. The results reveal a widespread use of subcontracting and sub‐subcontracting in the construction industry, primarily done to save time and money. Results show that substandard quality of work of subcontractors is the main problem area. Conversely, the use of direct labor was found to be an unprofitable proposition because of the high degree of uncertainty, fluctuations in construction workload and higher administrative overhead costs. Results show that 53% of the respondents are satisfied with their current subcontracting experiences, whereas 47% of the respondents want positive changes to be made in subcontracting arrangements. To rectify flaws in the existing subcontracting system, the following remedies were noted: 1) reduction in the number of layers or tiers of subcontracting to effectively manage the communication gap between prime contractor and subcontractor; 2) to establish mandatory subcontractor registration, prequalification and performance evaluations; 3) adopt a standardized form of contract between contractors and subcontractors; and, 4) develop the infrastructure for the technical training of subcontractors to improve construction quality. Further insights and discussions are given in the paper. The findings of this research will help subcontractors to improve their performance and assist stakeholders in the successful execution of a quality project through the judicious employment of subcontractors.

Select this Article		GIS Method for Haul Road Layout Planning in Large Earthmoving Projects: Framework and Case Study Sanghyeok Kang, Ph.D. and Jongwon Seo, Ph.D., P.E. Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000561 Posted ahead of print 30 March 2012 Full Text: \| Download PDF
	+ -	Show Abstract This study presents a Geographic Information System (GIS)‐based method for determining the optimal layout of a haul route for large earthmoving projects. The methodology focuses on the use of cost distance measurements to implement a least‐cost path analysis to calculate the route with the shortest weighted distance between cut and fill areas. Various factors such as truck speed, construction costs, and land use that influence haul road layout are investigated. Linear interpolations based on linguistic evaluations of experienced field experts are utilized to quantify the factors. An earthmoving project from a large scale dam construction was used as a case study to verify the applicability of the proposed method, and the route produced with the new method was compared to real road design data. The results showed the potential of the method as a practical approach to determining the optimal haul route for earthmoving.

Select this Article		Building Information Modeling in Support of Sustainable Design and Construction Patrick Bynum, Raja R. A. Issa, F. ASCE, and Svetlana Olbina, A. M. ASCE Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000560 Posted ahead of print 30 March 2012 Full Text: \| Download PDF
	+ -	Show Abstract The use of building information modeling (BIM) has provided a means of increasing total project quality, providing accurate quantity take‐offs and scheduling, and consequently diminishing total project contingencies and costs. Although BIM is a recent development, a lot of research has been conducted in order to further enhance the capabilities of BIM in design and construction. However, there has been very little research done so far on the impact that BIM has on sustainable construction practices. Hence, the goal of this research is to investigate the perceptions of the use of BIM for sustainable design and construction among designers and constructors. A survey was developed and administered via the Internet to determine the existing trends of BIM application in general as well as its use as a tool in sustainable design and construction. The survey results indicated that although the majority of the respondents believed that sustainable design and construction practices were of importance within their company, most still believed that sustainability was not a primary application of BIM and that project coordination and visualization were instead more important. While BIM is perceived as a multidisciplinary tool, problems with interoperability continue to persist among the various BIM applications in the industry. In terms of project delivery methods, the majority of the survey respondents believed that design‐build and integrated project delivery (IPD) are the optimal project delivery methods to integrate BIM as a sustainability tool. Although BIM is still a recent development, as more design and construction professionals understand the potential benefits offered through its use, BIM will become a vital tool for sustainable design and construction.

Select this Article		Modeling Profitability and Stock Market Performance of Listed Construction Firms on the Athens Exchange: A Two‐Stage DEA Approach Ioannis E. Tsolas Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000559 Posted ahead of print 30 March 2012 Full Text: \| Download PDF
	+ -	Show Abstract The purpose of this paper is to evaluate the performance of a sample of nineteen construction firms listed on Athens Exchange by applying a two‐step procedure. In the first step, data envelopment analysis (DEA) is used to model performance in two dimensions: profitability efficiency and efficiency in market value generating process. This allows us to independently identify the most efficient level of input in minimizing resources and the most efficient level of output in maximizing market value, various benchmarks, and the local returns to scale patterns of the firms of the sample in both performance dimensions. Moreover, we can examine whether there is a correlation between the performance efficiency scores. In the second step, regression models are used in order to identify the drivers of performance. Performance inefficiency is uncovered in both dimensions, but the real problem of inefficiency of the sampled firms is the lower level of performance in market value generating process, rather than profitability. The results revealed that profitability can be explained by selling and administrative cost‐to‐total‐revenue ratio and profit margin, while there is not much evidence for systematic effects of control variables on firm valuation. Results do not point out positive links between profitability efficiency and performance in the stock market. Most of the large, inefficient firms exhibit decreasing returns to scale (DRS) in the profitability dimension, whereas most of the inefficient firms exhibit increasing returns to scale (IRS) in the stock market performance dimension. Moreover, there is potential for the firms of the sample that operate under non‐DRS to accommodate and manage higher levels of business volume that will lead to increased level of market value. Implications of the study are also discussed.

Select this Article		Delivering Local Infrastructure through PPPs: Evidence from the School Sector Nuno Ferreira da Cruz and Rui Cunha Marques Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000558 Posted ahead of print 29 March 2012 Full Text: \| Download PDF
	+ -	Show Abstract This paper discusses the use of public‐private partnership (PPP) contracts in the school sector. With this purpose, four Portuguese case‐studies are carefully examined. We argue that the lessons provided by the literature are not being implemented by public authorities. In fact, while crafting these new governance structures, local governments seem to fail in protecting the public interest. To cope with this state of affairs, we draw a risk management strategy and advocate several contract management guidelines. Our findings suggest that increasing transparency in procurement procedures and fostering the standardization of the tender documents and contractual clauses are absolute requirements in achieving value‐for‐money. Albeit these best practices are now beginning to be prevalent among academics and practitioners, local decision‐makers still strive to cope with the complex process of handling the whole life‐cycle management of PPP arrangements.

Select this Article		Aggregate Blending Using Fuzzy Optimization Shinya Kikuchi, Ph.D. P.E., Professor, Nopadon Kronprasert, Graduate Student, and Said Easa, Ph.D. Professor Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000557 Posted ahead of print 26 March 2012 Full Text: \| Download PDF
	+ -	Show Abstract Aggregate blending is a process that blends available aggregates to create the blend which meets gradation specifications while minimizing the unit cost of the blend. Today's aggregate blending process, is a multi‐objective optimization problem that involves not only minimizing cost but also satisfying other specifications of the blend, such as fineness modulus, plasticity index, and specific gravity. Gradation limits are usually expressed in terms of the range for the percentage passing each sieve. In the traditional approach, rigid values are used for the gradation limits, and as a result, gradation and other specifications are frequently met at the limits during optimization, which is not particularly desirable. This paper proposes an approach for aggregate blending using fuzzy optimization method. The approach selects the best mix of aggregates such that the individual gradation specifications are met not only within the specification limits, but also their desirability within each range is satisfied as much as possible. In the proposed model, functions that represent the decision‐maker's satisfaction with respect to the blend's unit cost and physical properties are introduced. The proposed model is compared with two traditional optimization models using the example data found in two previous models. The results show that the proposed approach is useful for the real‐world application as it is robust in terms of its ability to deal with many constraints and objectives, practitioner's uncertainty about the limits of the specification ranges, and the desire to achieve different objectives.

Select this Article		Ergonomic Analysis and the Need for Its Integration for Planning and Assessing Construction Tasks Ndukeabasi Inyang, Mohamed Al‐Hussein, P.Eng., Marwan El‐Rich, and Saad Al‐Jibouri Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000556 Posted ahead of print 23 March 2012 Full Text: \| Download PDF
	+ -	Show Abstract The execution of daily construction tasks exposes workers to one or multiple ergonomic risk factors (awkward postures, static force, vibration, repetition, environmental risk, contact stress) and thus varying risks of developing musculoskeletal disorders. As a result, musculoskeletal disorders are common issues in construction, and result in costly delays and disability claims. Though there is recent research investigating the epidemiology and causal factors for musculoskeletal injury, the construction industry has not fully embraced this as part of its safety practices. This study presents state of the art ergonomic techniques, Canadian ergonomic legislations and Work Related Musculoskeletal Disorder (WRMSD) lost time claims statistics to show the resultant economic (cash and productivity) losses and adverse social (occupational health and safety) impact of WRMSDs resulting from current practice and legislation. Also, the potential short and long‐term productivity and cost merits of incorporating ergonomic assessments for construction tasks are presented.

Select this Article		Modeling Contingent Liabilities Arising from Government Guarantees in Indonesian BOT/PPP Toll Roads Andreas Wibowo, Andre Permana, S. M. ASCE, Bernd Kochendörfer, Robert Tiong Lee Kiong, M. ASCE, Dieter Jacob, and Dirk Neunzehn Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000555 Posted ahead of print 14 March 2012 Full Text: \| Download PDF
	+ -	Show Abstract By the end of 2010, the Government of Indonesia (GoI) issued a new regulation on government guarantee provision to protect project sponsors from government‐related project risks in public‐private partnered (PPP) infrastructure development. While the provision of guarantees can help improve the creditworthiness of PPP projects, it also may expose the GoI to considerable fiscal risk as a result of contingent liabilities the GoI incurs when providing guarantees. This requires a systematic contingent liability analysis to understand the full extent of their exposures. The present paper discusses simple and operational methodologies of quantifying payments of guarantees given to PPP toll road projects to protect project sponsors from skyrocketing costs of acquiring land, delays in scheduled toll adjustment, and compensation payments in case of nationalization. The paper also includes extensive modeling of key project risks i.e. land cost escalation, initial traffic volume, inflation rates, toll adjustment delays, and nationalization event. The methodologies are tested on a case study of a PPP toll road project in Indonesia implemented under a build‐operate‐transfer (BOT) arrangement to demonstrate its application. A Monte‐Carlo based simulation is performed to estimate two measures exposures that are the expected and excess payment of each guarantee. Although the discussion is framed within the context of specific sector and country, the methodologies offered herein can be adopted to other countries and sectors facing similar problems.

Select this Article		Request for Information: Benchmarks and Metrics for Major Highway Projects Awad S. Hanna, Ph.D., P.E., F. ASCE, Eric J. Tadt, E.I.T., and Gary C. Whited, P.E., M. ASCE Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000554 Posted ahead of print 8 March 2012 Full Text: \| Download PDF
	+ -	Show Abstract A Request for Information (RFI) is a formal written procedure initiated by the contractor seeking additional information or clarification for issues related to design, construction, and other contract documents. Large numbers of RFIs along with slow responses to RFIs are frequently cited as a metric for poor project performance. Implementation of a RFI process is an integral part of successful project management for construction projects which improves communication between the construction, design, and project management teams. The use of RFIs is common in vertical construction, but is just gaining use and acceptance in the delivery of transportation infrastructure projects. The purpose of this paper is to benchmark the RFI process and develop benchmarks and metrics to aid project teams in assessing the performance of a transportation infrastructure project, and provide best practices for improving the overall RFI process. Data on RFIs was collected from the construction of major highway projects in the Midwest including more than 65 bridges and 56 miles of roadway totaling $857.3 million of construction, in which two quantitative metrics were established for monitoring project performance. In addition, the paper provides reason codes developed for categorizing the type of RFI submitted and a method to identify problem areas.

Select this Article		A Balanced Framework for Measuring Performance of Supply Chains in House Building Johannes I. M. Halman and Johannes T. Voordijk Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000553 Posted ahead of print 7 March 2012 Full Text: \| Download PDF
	+ -	Show Abstract Despite its importance, performance measurement of supply chains of house building firms hasn't received much attention yet in academic literature. The objective of this study is to develop a framework to measure this performance. In a first step a comprehensive framework is developed composed of five main perspectives on the performance of supply chains in house building (i.e. Financial, Customer, Internal Business; External Business and Innovation) with 35 corresponding performance indicators. In the second step, the practical value of the proposed supply chain performance indicators is evaluated on its level of clarity, measurability and relative importance based on the feedback of senior purchasing managers of construction firms active in house building. The evaluation shows that the framework and its intended use are highly supported by these managers. In the final step, the management team of a medium‐sized construction firm active in house building used the framework to assess the firm supply chain performance relative to their competitors. It was concluded that the tool could be filled in easily and can be very helpful for getting insights in the supply chain performance of the firm.

Select this Article		Construction Small‐Projects Rework Reduction for Capital Facilities Di Zhang, Carl T. Haas, Paul M. Goodrum, Carlos H. Caldas, and Robin Granger Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000552 Posted ahead of print 3 March 2012 Full Text: \| Download PDF
	+ -	Show Abstract Rework is a persistent problem in construction. Reducing field rework is widely regarded as an effective way of improving construction performance in terms of productivity, cost, and schedule. While much literature exists concerning rework reduction, there is a need for further analysis, validation and improvement of rework reduction methods. This paper presents a generalized model for a rework reduction program, which is intended to reduce rework by managing a continuous improvement loop with four functional processes: (1) rework tracking and cause classification, (2) evaluation of rework and its causes, (3) corrective action planning, and (4) integration of changes into the total management system. Analysis is conducted to examine and verify the functional mechanisms and effectiveness of the generalized model, by investigating a rework reduction program implemented in practice for a series of dozens of small projects executed by three contractors that represents the generalized model, and by analyzing the impact trends on rework in terms of frequency, cost, and labor hours over a considerable time period. The paper's primary contribution to the overall body of knowledge is that it provides statistical evidence that the occurrence and impact of rework can be reduced significantly with such a program.

Select this Article		Case Study of Mass Customization of Double‐Curved Metal Façade Panels Using a New Hybrid Sheet Metal Processing Technique Ghang Lee and Seonwoo Kim Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000551 Posted ahead of print 3 March 2012 Full Text: \| Download PDF
	+ -	Show Abstract Despite general perceptions, mass customization of double‐curved metal panels with slight variations remains challenging. We report the results of a 3‐year effort to develop a new hybrid sheet metal processing technique to fabricate double‐curved metal panels for the Dongdaemun Design Park (DDP) building. DDP, designed by Zaha Hadid, has an unusually high percentage of double‐curved panels. Among the 45,000 façade panels, approximately 22,000 panels are double‐curved. Despite the complexity and the large number of different types of panels, the joints are only 25 mm wide. Precision and a limited budget were the key requirements. The project team successfully developed a new and affordable sheet metal forming method called multi‐point stretch forming, which is a hybrid method of multi‐point forming and stretch bending, through trial‐and‐error. Several machines and prototypes were custom‐built and tested. The cost of fabrication of typical double‐curved panels using this new method was USD 260 per square meter compared to USD 7,000 per square meter when die casting was used and USD 3,000 per square meter when hydroforming was used. Furthermore, the average fabrication time per panel was reduced from several hours to 15 minutes per panel when using the new multi‐point stretch forming method.

Select this Article		Change Orders and Lessons Learned: Knowledge from Statistical Analyses of Engineering Change Orders on Kentucky Highway Projects Timothy R. B. Taylor, Moin Uddin, Paul M. Goodrum, Alex McCoy, and Yongwei Shan Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000550 Posted ahead of print 3 March 2012 Full Text: \| Download PDF
	+ -	Show Abstract While change orders occur on many construction projects, data examined herein suggest that many change orders can be avoided on roadway construction projects through improved project planning and scoping. Statistical analyses of change orders on 610 Kentucky roadway construction projects from 2005 to 2008 examined how the causes of change orders varied between construction versus maintenance projects, different road types (e.g. state highways, interstate, and county roads), and construction type (e.g. earth work, structures, and road surfacing). The research examined the risk posed by engineering change orders by measuring the frequency and average percentage change in project costs for different types of change orders. While the relative impacts did vary by analyses, the leading causes of change orders within the state consistently included contract omissions, owner induced enhancements, and contract item overrun. The paper's primary contribution to the overall body of knowledge is the establishment of evidence that many high risk change orders on roadway construction projects can be avoided through improved front‐end planning while avoidance of other change orders, such as fuel and asphalt price adjustments, are more challenging since they can be due to rapidly changing market conditions. The results show not only distinctive trends that are useful for constructability reviews on future projects but also identify the need for new directions in front end planning and project scoping to minimize change orders on highway projects.

Select this Article		A Framework for Estimating Greenhouse Gas Emissions Due to Asphalt Pavement Construction Byungil Kim, Hyounkyu Lee, Hyungbae Park, and Hyoungkwan Kim Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000549 Posted ahead of print 3 March 2012 Full Text: \| Download PDF
	+ -	Show Abstract Since the Kyoto Protocol of 1997, greenhouse gas (GHG) emissions have gained importance as one of the main criteria for environmental evaluation. As a project evaluation criterion, this study developed a framework that could estimate GHG emissions in asphalt pavement construction based on the limited information available in the feasibility study phase. A thorough literature review and in‐depth interviews with domain experts in the field of road engineering were conducted to identify the input variables for this framework. By considering the characteristics of the input variables, such as material type, geometric shape of the structure, and earthwork quantities, an artificial neural network and a parametric calculation were used to develop the framework for estimating GHG emissions. When applied to real‐life asphalt pavement projects in the Republic of Korea, the framework produced an average estimation error of 11.2% was observed, which was considered sufficiently accurate for the planning phase. The proposed framework is expected to help decision makers easily evaluate the GHG emission potential of asphalt pavement projects in their preliminary phase such that project viability and priority can be determined in a more holistic manner.

Select this Article		Construction Project Risk Management Based on the View of Asymmetric Information Pengcheng Xiang, Jin Zhou, Xiaoyu Zhou, and Kunhui Ye Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000548 Posted ahead of print 3 March 2012 Full Text: \| Download PDF
	+ -	Show Abstract Construction projects are facing a greater number of uncertainties and more severe risks, which could cause much bigger losses than in the past. From the perspective of information economics, asymmetric information gives rise to opportunistic behavior, which is the primary cause of loss of faith and increased risk in the construction market. Asymmetric information theory is helpful for solving problems arising in construction projects and for preventing construction project risk. Our main objective in this paper is to explore risk prevention mechanisms and measures in construction projects based on asymmetric information theory. The research processes are: (1) exploring the relationship between asymmetric information and construction project risk and exploring the mechanisms of construction project risk formation based on asymmetric information; (2) analyzing the issue of asymmetric information in construction projects and creating an information model of construction project management; (3) proposing measures for resolving information asymmetries of construction projects. The contributions to the literature are: (1) an application of asymmetric information theory to construction project management, and confirming that asymmetric information theory is helpful for resolving problems and preventing construction project risk; (2) showing that incomplete information, especially asymmetric information, is the essential cause of construction project risk.

Select this Article		A Web‐Based Risk Assessment Tool Using Integrated Duration — Cost Influence Network Model Irem Dikmen, Prof. Dr., M. Talat Birgonul, Prof.Dr., Joseph H. M. Tah, Prof.Dr., and Ahmet Hamdi Ozer, Civil and Mechanical Engineer Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000547 Posted ahead of print 21 February 2012 Full Text: \| Download PDF
	+ -	Show Abstract The major challenges of project risk assessment may be attributed to knowledge requirements for determining the level of uncertainty and development of complex models to predict project outcomes. The duration‐cost influence network is an adequate model which can be used for activity‐based risk modeling. In this study, a scenario analysis feature is added to this model and a web‐based tool is developed which can be used to calculate risk‐adjusted duration and cost considering the risks affecting cost and duration of individual activities. Monte Carlo Simulation is used to create scenarios and the output of these scenarios is calculated by using the cost‐duration influence system that simulates the vulnerability of the project to the identified risk factors. The web‐ based tool can be used by decision‐makers during the pre‐planning stage of construction projects to estimate cost and duration implications of various risk occurrence scenarios, determine contingencies and prepare risk management plans.

Select this Article		Unit Costs of Public and PPP Road Projects: Evidence from India Surya Sudheer Meduri and Thillai Rajan Annamalai Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000546 Posted ahead of print 16 February 2012 Full Text: \| Download PDF
	+ -	Show Abstract There has been an overall increase in the level of private sector investment in road sector in many developing countries during the past decade. However, there has been limited research on the impact on such increased private sector participation on road costs. Using data on 521 public and private road projects from India it was found that there are significant differences between public and private sector projects. PPP roads have a longer length, higher project cost, and lower unit costs as compared to public projects. Though regression analysis indicated that private sector investment tended to increase unit costs, PPP road projects were able to achieve lower unit costs by taking advantage of the economies of scale. It was also found that the presence of foreign sponsors in the private consortium and prevalence of corruption increased unit costs. Results from a logistic regression analysis indicated that states that are more developed and having lower levels of corruption can be more successful in attracting private sector investment for road projects.

Select this Article		Public Financing into Build‐Operate‐Transfer Hospital Projects in Italy Alberto De Marco, Giulio Mangano, Anna C. Cagliano, and Sabrina Grimaldi Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000545 Posted ahead of print 16 February 2012 Full Text: \| Download PDF
	+ -	Show Abstract An empirical analysis is presented to investigate the factors that have significant influence on the share of public financing into the total initial investment required to develop Build‐Operate‐Transfer (BOT) healthcare projects. Based on a model describing the main risks associated with public participation in BOT projects, a linear regression analysis has been carried out on a dataset of Italian BOT hospital projects to yield implications. Outcomes reveal that the size of investment, the financial strength of the concessionaire, the duration of the concession period, the number of services, and the level of borrowing of the local healthcare granting agency are significant factors of the level of public funding. The study confirms that public funding is not only provided to cover the non self‐financing portion of investment, but also as a way to undertake a project in periods of scarce public financial resources. The methodology may be useful to refine the decision criteria for determining the level of public funding in the capital structure of a BOT hospital project in order to gain an understanding of the value for money that can be obtained from funding non‐freestanding social facility projects.

Select this Article		Strategies for Integrating the Use of Offsite Production Technologies in Housebuilding Wei Pan, Alistair G. F. Gibb, and Andrew R. J. Dainty, M. ASCE Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000544 Posted ahead of print 13 February 2012 Full Text: \| Download PDF
	+ -	Show Abstract Despite extensive research into attitudes and practice surrounding the uptake of offsite production technologies, there is limited understanding of how best to integrate their use into business processes at organizational level. Drawing on an action‐research case study with a leading UK housebuilding organization this paper scrutinizes the processes through which offsite technologies were adopted and utilized. The use of offsite was fundamentally framed by the key stages and business milestone reviews of the housebuilding process, which together represented a complex and multi‐layered structure of business management. Five offsite reviews were aligned with the business processes. Strategies for integrating the use of offsite technologies are examined. It was crucial to establish an overall offsite strategy and integrate it into the process from land acquisition on. Organizational learning embraced the adoption of offsite, while extra reporting and management efforts introduced bureaucracy. Culture change was commonly perceived difficult and painful. Earlier engagement with supply chains was advocated for favoring the offsite approach and improving business efficiency, whilst it also demanded greater commitment of the housebuilder to specific supply chains and therefore exposed the business to risks associated with planning and market changes. The strategies should facilitate building companies’ strategic management of offsite technology.

Select this Article		Establishing and Weighting Decision Criteria for Building System Selection in Housing Construction Wei Pan, Andrew R. J. Dainty, M. ASCE, and Alistair G. F. Gibb Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000543 Posted ahead of print 13 February 2012 Full Text: \| Download PDF
	+ -	Show Abstract A lack of value‐based decision criteria leads to an inability to effectively compare prefabrication and offsite production with conventional construction, which inhibits the realization of benefits of offsite approaches. This paper develops value‐based decision criteria and quantifies their relative importance, for assessing building technologies systematically. The research employed a multi‐methodological strategy within a broad case‐study based design, with six large housebuilding organizations in the UK. These companies together accounted for over a tenth of new‐build homes completions in the UK. Over fifty criteria were developed, grouped under cost, time, quality, health and safety, sustainability, process, procurement, and regulatory and statutory acceptance. Cost was ranked most important, which, coupled with time and quality, predominated technology selection in these companies. Sustainability, process and procurement were weighed lower, while health and safety and regulatory and statutory acceptance were deemed compulsory, hence offering no trade‐off opportunity. A lack of incorporating innovative sustainable technology into corporate strategy is observed. The developed criteria and the systematic process should help housebuilding organizations manage technological innovation and hopefully achieve more informed corporate decisions.

Select this Article		Detection of Collusive Behavior Ranon Chotibhongs and David Arditi Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000542 Posted ahead of print 11 February 2012 Full Text: \| Download PDF
	+ -	Show Abstract Collusion is an insidious issue in the construction industry. Even though it is widely acknowledged as unethical and illegal, there are not many research studies conducted to detect collusive bidding. This study proposes a step‐by‐step method to detect collusive bidding by analyzing historical bidding data provided by a construction owner. The construction owner in this study is a public agency that commissioned 108 construction projects that was worth $1.3 billion during a 10‐year study period (2001–2010). The number of bidders (80 in total) was small considering that a total of 108 contracts were awarded in the study period. Five of the eighty bidders jointly undertook 72% of the total contracts awarded by this public agency during the study period. The proposed detection method is based on a regression model and involves indentifying the potential cartel bidders using two tests called the residual test and the cost structure stability test. After conducting the study, it was found that two of the six potential cartel bidders that were identified in this study had been audited by the public agency for bid fraud, and that another potential cartel bidder had been found guilty by the courts and forbidden from doing business with the public agency.

Select this Article		The Influence of Dispersion and Location on Pay Adjustment in Construction Engineering F. G. Praticò, Antonio Casciano, and Domenico Tramontana Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000540 Posted ahead of print 10 February 2012 Full Text: \| Download PDF
	+ -	Show Abstract Acceptance procedures are usually defined in terms of the fraction of elements that fall outside of certain specification limits, such as the data dispersion around a central tendency. In contrast, design methods usually consider measures of a central tendency or location (i.e., mean) or, occasionally, on a central tendency together with measures of data dispersion. Price adjustments can be derived from data analysis using empirical models or algorithms based on life cycle cost analysis. As a consequence, there is no common logical framework for designing, analyzing, testing, and accepting road and airport pavements. This study analyzes the dependence of pay adjustment on hot mix asphalt air void characteristics using several acceptance procedures. The results demonstrate that the transition from location‐based to dispersion‐based systems depends on the probability density function describing a given quality characteristic. The drawbacks of several methods, brought to light in the analysis and discussion presented here, informed a new model in which both location and dispersion indicators are considered. The model was applied to a case study, and practical applications are outlined.

Select this Article		Evaluating the Quality Performance of Pavement Contractors Firuzan Yasamis‐Speroni, Dong‐Eun Lee, and David Arditi Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000539 Posted ahead of print 10 February 2012 Full Text: \| Download PDF
	+ -	Show Abstract This paper introduces a contractor quality performance (CQP) evaluation model that measures the quality performance of pavement contractors. The model uses a modified Quality Function Deployment model to support the quality performance measurement that is involved in multi‐attribute and multi‐participant decision‐making and the Delphi method to deal efficiently with the uncertainties in the input data. State DOTs who are in the process of selecting a pavement contractor for a project would benefit from the CQP evaluation model, because the system allows a client to expeditiously assess the quality performance of potential pavement contractors in their bidding list. A test case is presented to illustrate the functioning of the model. The model contributes to improve the quality of the nation's pavements because it enhances the contract administration procedures by reengineering the current contractor assessment, prequalification and/or selection process within the owner organizations (State Departments of Transportation) by accentuating total client (both the road‐users’ and the owners’) satisfaction. The model helps to improve the state DOT's pavement project bidding system.

Select this Article		Success Traits for a Construction Project Syed Zafar Shahid Tabish and Kumar Neeraj Jha Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000538 Posted ahead of print 6 February 2012 Full Text: \| Download PDF
	+ -	Show Abstract Ensuring successful outcome in a construction project has always been the aim of the construction project manager and project management is used as a tool to achieve this goal. Based on the assumption that the project success is repeatable, researchers have indicated certain attributes/factors, which when present in a project, are likely to make it successful. Traditionally, schedule, cost and quality compliances, commonly referred to as ‘iron triangle’, have been accepted as the most widely used criteria to define the success. In this study, it is hypothesized that ‘project success’ is influenced by ‘success traits’. ‘Success traits’ has been defined as a second‐order construct composed of two latent constructs, human factors and management actions. We find that human factors play a decisive role in making a project successful. The observed variables under these constructs were taken from a past study. The structural equation modeling technique has been used to test the hypothesized positive interrelationships between success traits and project success. The approach used in this study could be a good value addition in the field of construction management. Besides, the results would enable practitioners to focus on fewer factors rather than attending to numerous factors without getting commensurate returns.

Select this Article		Integrative Model for Quantitative Evaluation of Safety on Construction Sites with Tower Cranes Aviad Shapira, F. ASCE, Meir Simcha, and Marat Goldenberg Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000537 Posted ahead of print 2 February 2012 Full Text: \| Download PDF
	+ -	Show Abstract The gradual disappearance of traditional borderlines between equipment cultures and the increasing use of tower cranes as today's dominant building construction equipment result in exposure to safety issues concerning tower crane operation that have not yet been fully addressed. The current paper proposes a model capable of computing an overall index that realistically reflects the safety level on any individual site due to the operation of tower cranes. The model integrates four modules: (1) non‐site‐specific relative weights of safety factors; (2) measurement of the magnitude of each safety factor actually present on site; (3) scales to convert each measured magnitude into a value representing the potential risk generated by each factor present on site; and (4) multiplying factors to convert the cumulative risk generated by all factors into actual risk. The model was computerized and tested on two construction sites and the user interface for company and site data gathering was validated. The development of the model builds on expert judgment and as such, its potential application in other construction cultures would require due adjustments, which are made possible by its modular architecture and content transparency.

Select this Article		An Automated Time‐Series Cost Forecasting System for Construction Materials Sungjoo Hwang, Moonseo Park, M. ASCE, Hyun‐Soo Lee, M. ASCE, and Hyunsoo Kim Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000536 Posted ahead of print 2 February 2012 Full Text: \| Download PDF
	+ -	Show Abstract As large‐scale building projects increase in frequency, their construction costs become a matter of great concern, especially because of their lengthy construction periods. In particular, recent volatile fluctuations of construction material prices fueled problems like cost forecasting. Many researchers tried to accurately estimate cost escalations, but price forecasting for numerous construction materials requires a simplified and automated process. The research in this paper, therefore, develops an automated time‐series material cost forecasting (ATMF) system including both auto‐selected procedures for determining a best‐fitting model, as well as an auto‐extracting module for forecast values using the Box‐Jenkins approach. By simplifying the modeling process and eliminating iterative arbitrary decisions for the modeler, a large number of material prices can be forecast each. Thus the ATMF system can be utilized for predicting future trends in construction material costs. Further, the out‐of‐sample forecast applying several material prices data confirm that this system can be effectively applied to material cost estimation with the more detailed level in object‐based cost planning. The proposed system can thus help construction practitioners deal with changes in economic conditions and design by estimating cost escalations caused by volatile factors such as inflation.

Select this Article		Controlling Path and Controlling Segment Analysis in RSM Lihui Zhang and Jianxun Qi Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000535 Posted ahead of print 2 February 2012 Full Text: \| Download PDF
	+ -	Show Abstract The controlling path and controlling segment are the basis for repetitive project scheduling. In this paper the controlling path is defined as the longest path in duration which determines the minimum project duration, including the controlling segments and controlling constraints on it. The controlling segments are defined as the sub‐activities on the controlling path. A method to identify the controlling path and controlling segments is proposed, based on the technology of identifying the potential controlling points. To investigate how the project duration is determined, three types of controlling segments are defined and analyzed, namely, the forward controlling segment, the point controlling segment, and the backward controlling segment. This paper presents a convenient and correct way to identify the controlling path and controlling segments conforming to the constraints of projects.

Select this Article		The Distinction between Team‐Based Self‐Esteem and Company‐Based Self‐Esteem in the Construction Industry Zhikun Ding, Fungfai Ng, Jiayuan Wang, and Liang Zou Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000534 Posted ahead of print 2 February 2012 Full Text: \| Download PDF
	+ -	Show Abstract Organization‐based self‐esteem has been a key construct in organizational management research since it was proposed by Pierce et al. in 1989. However, this paper proposes that organization‐based self‐esteem should be further refined as team‐based self‐esteem and company‐based self‐esteem, particularly in the construction industry. The construct of team‐based self‐esteem is defined and distinguished from company‐based self‐esteem. Based on survey data and results of exploratory, confirmatory factor analysis and structural equation modeling, the convergent, discriminant and predictive validity of team‐based self‐esteem and company‐based self‐esteem are tested and verified. The result shows that team‐based self‐esteem is more salient than company‐based self‐esteem and has better predictive power in the construction project team context. The significant implication is that research of self‐esteem in the construction industry should measure self‐esteem depending on the research context e.g. team‐based instead of company‐based self‐esteem in project management research.

Select this Article		Managing the Stress of Hong Kong Expatriate Construction Professionals in Mainland China: A Focus Group Study Exploring Individual Coping Strategies and Organizational Support Isabelle Yee Shan Chan, Mei‐yung Leung, and Sherwood Shi Wang Yu Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000533 Posted ahead of print 2 February 2012 Full Text: \| Download PDF
	+ -	Show Abstract The rapid expansion of the construction industry in Mainland China has made it increasingly common nowadays for Hong Kong construction professionals (HK‐CPs) to work in Mainland China as expatriates. As the unfamiliar working and living environment there further escalates the stress levels of these professionals, the current study aims to explore and investigate: i) the experience with stress of Hong Kong expatriate construction professionals in Mainland China (HKE‐CPs‐M), ii) the various individual coping strategies they adopt to cope with stress, and iii) the forms of organizational support that are effective in handling stress. Six focus groups, including four groups of HKE‐CPs‐M working in various cities in Mainland China (Beijing, Shanghai, Guangzhou, and Macau), a repatriate group comprising repatriate HK‐CPs from Mainland China, and a group comprising HK‐CPs without expatriate experience, were conducted in the study. HKE‐CPs‐M from all groups had experienced stress in their expatriate assignments in Mainland China. In group discussions, the participants identified six individual coping strategies and three forms of organizational support. To critically explore the coping strategies and organizational support for HKE‐CPs‐M, items addressed by the HKE‐CPs‐M groups and the HK‐CPs group were compared. Lastly, various recommendations are made for both individual HKE‐CPs‐M and related construction organizations.

Select this Article		Assessment of the Productivity of Nighttime Asphalt Paving Operations: A Case Study Ali Mostafavi, Vanessa Valentin, Dulcy M. Abraham, and Joseph Louis Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000531 Posted ahead of print 20 January 2012 Full Text: \| Download PDF
	+ -	Show Abstract Performing highway construction operations in the nighttime hours has emerged as a response to traffic congestions caused by daytime lane closures. Work zone conditions at night may be different from those during the day, and the nighttime factors affecting the project metrics (i.e., safety, quality, and productivity) should be carefully considered during the planning of nighttime projects. In the existing body of knowledge, there is no methodology for quantifying the effects of nighttime factors on the productivity of construction operations. The objective of this study therefore is to create a methodology to quantify the effects of nighttime factors that disrupt productivity, specifically, in asphalt paving projects. The study will analyze the impact of factors, such as visibility, personnel fatigue, and glare, on nighttime paving projects. The methodology developed in this study is demonstrated using an example case. First, the nighttime qualitative (subjective) factors affecting the productivity of asphalt paving operations are identified. A productivity index (PI) then is estimated to account for the effects of the nighttime qualitative factors on the productivity of this operation. The PI value subsequently is used to modify the baseline productivity simulated by a discrete event model of a paving operation and is then compared to the actual productivity of the case study project. The analysis indicates that the productivity of the asphalt paving operation in the case study can be predicted within an acceptable accuracy range, implying that the calculated nighttime productivity index can capture the effects of nighttime factors on the productivity of asphalt operations to an acceptable extent for the case study project under consideration. Quantification of the effects of nighttime factors could help practitioners understand the extent of these effects on their projects. Since nighttime operations are usually more expensive due to overtime payments, night premium payments, lighting expenses, and costs associated with enhanced traffic control, a better estimate of the productivity, while accounting for the effects of nighttime factors, during the early stages of the project could lead to better planning and could result in cost savings.

Select this Article		Engineer Self‐Evaluation Checklist for Effective Site Visits Andrew S. Chang, Sin‐Jing Du, and Fang‐Ying Shen Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000530 Posted ahead of print 19 January 2012 Full Text: \| Download PDF
	+ -	Show Abstract Site visits are necessary and important for construction projects. Construction engineers spend a lot of time on site visits, but the effectiveness of the visits has not been explored and their effect on project performance is unclear. In this study, a checklist to improve the effectiveness of site visits was developed based on site visit deficiencies and construction productivity factors found in recent literature, and the most frequently occurring defects from 338 construction projects. The checklist was then used on eight on‐going road and bridge projects to test its applicability and effectiveness. Results show that proper use of the checklist by contractors indicated a high level of project quality. Time spent on site visits was also reduced through the use of the checklist. This research links site visit practices with management knowledge such as work planning, quality management, and coordination. The developed checklist incorporates management knowledge as a systematic tool that complements the technical checklists to guide and improve the effectiveness of site visits.

Select this Article		Multiplier Model for Forecasting Manpower Demand Chun‐pong Sing, Peter E. D. Love, and C. M. Tam Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000529 Posted ahead of print 14 January 2012 Full Text: \| Download PDF
	+ -	Show Abstract To better manage and forecast the demand for labor in the construction industry, a mathematical model is developed using a distributed lag model and labor multiplier approach. The model is tested using economic statistics and manpower data derived from Hong Kong construction projects. The model can be used by public and private sectors to forecast future labor demand so that an optimal workforce can be attained.

Select this Article		The Mediating and Moderating Effect of Tension on Withdrawal‐Commitment Relationship in Construction Dispute Negotiation Pui Ting Chow, Fung Kong, and Sai On Cheung Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000528 Posted ahead of print 14 January 2012 Full Text: \| Download PDF
	+ -	Show Abstract Negotiation is the most cost effective way to resolve construction dispute. The success or otherwise of a negotiation depends very much on the commitment of the negotiators for a settlement. Withdrawal refers to a situation when a construction negotiator loses the interest to continue with a negotiation. A withdrawing negotiator is having the propensity to abandon a negotiation. It is proposed that withdrawal and commitment in negotiation are linked. The higher the commitment of the negotiators, the greater the chance a negotiated settlement can be achieved. This withdrawal‐commitment relationship is further influenced by tension that the negotiators face. Being tensed or relaxed is having a bearing on the cognitive reasoning of a negotiator. The roles and impact of tension on the withdrawal‐commitment relationship are investigated in this study. Two hypotheses have been developed: 1) tension mediates the withdrawal‐commitment relationship and 2) tension moderates the withdrawal‐commitment relationship. Certain level of tension helps negotiators to stay focused on the disputing issues and engenders commitment. With data collected from experienced construction dispute negotiators, regression analyses were carried out to test the hypotheses. Tensioned negotiators are generally more committed to negotiated settlement than their low‐tensioned counterparts. However, if withdrawing tendency reaches its threshold value, the loss of commitment of high‐tensioned negotiators is much quicker than the low‐tensioned counterparts. It reminds managers that tension can mobilize human resources to the betterment of a negotiated settlement, but too much of the tension would raise the state of withdrawal of the negotiators and in terms lowers commitment. In this regard, management may adjust the tension level by varying the settlement targets as well as changing the memberships of the negotiation team.

Select this Article		A Statics‐Based Simulation Approach for Two‐Crane lift Yuanshan Lin, Di Wu, Xin Wang, Xiukun Wang, and Shunde Gao Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000526 Posted ahead of print 20 December 2011 Full Text: \| Download PDF
	+ -	Show Abstract Cooperative cranes are widely used in modern construction projects and can reduce the cost and time of heavy lift. The safety of cooperative crane lift can be improved by using simulation method. This paper proposes a statics‐based simulation approach for two cooperative cranes, which could accurately determine the slopes and the tensions of the lifting cables. The proposed approach utilizes the principle of minimum potential energy to transform the problem of determining the slopes and tensions of lifting cables to an optimization problem with geometric and physical constraints. The accuracy is verified by comparing with results of ADAMS simulation in different scenarios. Physical properties are taken into account in this approach to make sure that the two‐crane cooperative lifting simulation is close to actual lift. The proposed method has been incorporated into a computer‐aided system by Sinopec, which assists planners in developing reliable lifting plans more efficiently. The effectiveness and usability of the developed algorithm is shown using an actual case.

Select this Article		Analysis of Arizona's LEED for New Construction Population's Credits Kenneth Timothy Sullivan, PhD, MBA and Hugo Dixon Oates, M.S. Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000525 Posted ahead of print 20 December 2011 Full Text: \| Download PDF
	+ -	Show Abstract Existing literature has failed to identify credit patterns amongst buildings that have achieved various certification levels within the Leadership in Energy and Environmental Design for New Construction (LEED NC) rating system. While credit scorecard information had been available for some LEED NC certified projects on the United States Green Building Council's (USGBC) website, no one had published a detailed credit analysis or overall credit trends. Additionally, the few studies that correlated LEED credits to utility consumption returned null results. This technical paper examines LEED NC credit trends for 91 percent of Arizona's 53 building LEED NC building population in an effort to identify credit patterns and to determine if credits correlate with either water or power consumption. Data collection efforts were successful for all desired deliverables except water consumption. Credit patterns emerged, exhibiting the most and least commonly attained credits, identifying differences between consultant populations and demonstrating credit strategy patterns inherent in each progressively more demanding certification level. Water collection was unsuccessful, rendering water correlations impossible. Collection of energy consumption data was successful, yet produced few statistically significant correlations. The study's results demonstrate to industry practitioners and researchers that the 69 point LEED NC rating system failed to demonstrate substantial correlations between energy use and credits within the Arizona population, thereby discounting energy conservation strategies inherent in LEED NC versions 2.0, 2.1 and 2.2. The results also highlight the need to incentivize those credits which produce the greatest environmental benefit throughout the building's full life cycle. Energy correlations are discussed in greater detail in the authors' paper titled “Post Occupancy Energy Consumption Survey of Arizona's LEED New Construction Population.”

Select this Article		Using Pajek™ and Centrality Analysis to Identify a Social Network of Construction Trades Brad W. Wambeke, Min Liu, and Simon M. Hsiang Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000524 Posted ahead of print 16 December 2011 Full Text: \| Download PDF
	+ -	Show Abstract Construction project managers are often faced with the challenge of managing a complex construction process consisting of multiple trades working on a large number of interdependent tasks. A social network is pattern of ties that exist between different entities (i.e. people, organizations, countries, etc.). There is an underlying social network of trades that exists with a construction project and recognizing it can help a management team succeed in this challenging environment. A $50M project involving 43 trades was studied over a 28 week period. Pajek™, a social network analysis program, was used to generate a series of 14 social networks for the trades involved. Both degree and eigenvector centrality were analyzed to reflect the distribution of relationships through the network and to identify the key trades. This research is useful to project managers and is significant as it outlines and illustrates a method of identifying the underlying network and and associated key trades of a construction project based on spatial proximity. While this research is based upon an individual case study, the apsects of this research are repeatable. The methods presented in this paper will enable others to develop a social network that is tailored for a specific aspect of a project, ranging from contract development teams to the individual trades using a CPM schedule.

Select this Article		Facing Turbulence — A Driving Force for Construction Organizations to Regain Unlearning and Learning Traction Peter Shek Pui Wong and Ka Yin Lam Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000523 Posted ahead of print 10 December 2011 Full Text: \| Download PDF
	+ -	Show Abstract Organizational learning (OL) is recognized as being crucial in construction organizations' performance. Nevertheless, scholars have argued that construction organizations do not seem to learn in a manner that fosters resilience in coping with changes in developers' demands. Skeptics argue that OL should be facilitated by unlearning (UL) ‐ a process of discarding obsolete beliefs and routines. While OL has emerged as a popular construction management research topic, it is a concept that has yet to be investigated empirically from an unlearning perspective. This paper reports a study that aims to: (1) investigate the effect of OL and UL on the performance of construction organizations; and (2) investigate the role turbulence (TU) plays on triggering OL and UL. Data was collected from a questionnaire survey conducted in Hong Kong, and the Structural Equation Modeling (SEM) technique was employed for data analysis. The results indicate that: (1) TU triggers the process of UL; and (2) UL significantly contributes to the practice of OL in construction organizations. These results imply that if construction organizations unlearn, they could be more capable of learning to enhance performance. Furthermore, turbulence is found to be a motivation for unlearning. This study contributes to the research of OL in construction by providing possible reasons leading to the construction organizations being incapable of learning. Furthermore, additional research is recommended on ways to facilitate construction organizations' unlearning.

Select this Article		Determining the Appropriate Proportion of Owner‐Provided Design in Design‐Build Contracts — A Content Analysis Approach Bo Xia, Albert Chan, Keith Molenaar, and Martin Skitmore Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000522 Posted ahead of print 10 December 2011 Full Text: \| Download PDF
	+ -	Show Abstract The Request For Proposal (RFP) with the design‐build (DB) procurement arrangement is a document in which an owner develops his requirements and conveys the project scope to DB contractors. Owners should provide an appropriate level of design in DB RFPs to adequately describe their requirements without compromising the prospects for innovation. This paper examines and compares the different levels of owner‐provided design in DB RFPs by the content analysis of 84 requests for RFPs for public DB projects advertised between 2000 and 2010 with an aggregate contract value of over $5.4 billion. A statistical analysis was also conducted in order to explore the relationship between the proportion of owner‐provided design and other project information, including project type, advertisement time, project size, contractor selection method, procurement process and contract type. The results show that the majority (64.8%) of the RFPs provide less than 10% of the owner‐provided design. The owner‐provided design proportion has a significant association with project type, project size, contractor selection method and contract type. In addition, owners are generally providing less design in recent years than hitherto. The research findings also provide owners with perspectives to determine the appropriate level of owner‐provided design in DB RFPs.

Select this Article		Governance of Learning Mechanisms: Evidence from Construction Firms Le Chen and Patrick S. W. Fong Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000521 Posted ahead of print 10 December 2011 Full Text: \| Download PDF
	+ -	Show Abstract The focus of knowledge management (KM) in the construction industry is moving towards capability building for value creation. The study reported by this paper is motivated by recent assertions about the genesis and evolution of knowledge management capability (KMC) in the strategic management field, and attempts to shed light on the governance of learning mechanisms that develop KMC within the context of construction firms. A questionnaire survey was administered to a sample of construction contractors operating in the very dynamic Hong Kong market to elicit opinions on the learning mechanisms and business outcomes of targeted firms. Based on a total of 149 usable responses, structural equation modeling (SEM) analysis identified relationships among knowledge governance mechanisms, knowledge processes and business performance, thereby supporting the existence of strategic learning loops. The study findings provide evidence from the construction context for capability assertions that knowledge governance mechanisms and processes form learning mechanisms that carry out strategic learning to create value, effect performance outcomes and ultimately drive the evolution of KMC. The findings imply that it is feasible for managing construction firms to govern learning mechanisms through managing the capability‐based holistic KM system, thereby reconfiguring KMC to match needs in the dynamic market environment over time.

Select this Article		Panel Stacking, Panel Sequencing and Stack Locating in Residential Construction: A Lean Approach John P. Shewchuk, Ph.D. and Cheng Guo, Ph.D. Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000520 Posted ahead of print 8 December 2011 Full Text: \| Download PDF
	+ -	Show Abstract A current trend in residential construction is the use of prefabricated wall panels. Panels are manufactured at a factory, then arranged into stacks for transporting to the construction site, where they are assembled. Current approaches to planning panelized construction are focused on stacking and transport efficiency, with little consideration given to assembly. This results in excessive panel material handling during construction, increased construction lead time, and increased risk of worker overload and/or injury. This paper proposes a lean approach to panel stacking, panel sequencing and stack locating, where panels within each stack form a continuous structure and are erected via continuous flow. The objectives are to minimize the quantity of stacks, panel material handling distance, and the work required to position and brace panels: panel interference is ignored. Few researchers have addressed this problem: a single algorithm has been reported, and this only works for certain building shapes and may provide infeasible solutions. The proposed approach and algorithm result in improved performance, have no shape restrictions, and always provide feasible solutions. Additionally, computational experiments show that the algorithm outperforms methods being employed in the construction industry today.

Select this Article		Comparative Analysis of Safety Culture Perceptions among HomeSafe Managers and Workers in Residential Construction David P. Gilkey, Carla Lopez del Puerto, Thomas Keefe, Philip Bigelow, Robert Herron, John Rosecrance, and Peter Chen Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000519 Posted ahead of print 8 December 2011 Full Text: \| Download PDF
	+ -	Show Abstract Construction workers continue to experience high rates of injury and illness compared to many other industries. There is growing evidence that safety culture has a direct effect on safety performance. This study investigated measures of safety culture and risk perception among a residential home building cohort within the HomeSafe Pilot Program in the Denver Metro area of Colorado. Investigators compared group level responses of management to frontline construction workers. Results indicate that managers appraised the overall safety culture at higher levels compared to the workers. Managers also perceived a higher level of management commitment to safety and health than that reported by workers.

Select this Article		Developing a Versatile Subway Construction Incident Database (SCID) for the Safety Management Zhipeng Zhou, Qiming Li, and Weiwei Wu Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000518 Posted ahead of print 8 December 2011 Full Text: \| Download PDF
	+ -	Show Abstract It is very difficult to implement Quantitative Risk Assessment (QRA) for the safety management in subway construction, due to the shortage of sufficient information about accidents happening in subway construction. QRA contains statistical analysis of incidents, calculation of safety precursors, foundation of precursor early‐warning system, etc.. In order to enhance the possibility of QRA and further the safety management in subway construction, a versatile subway construction incident database (SCID) was developed. SCID is composed of three kinds of incidents, inclusive of accidents, near‐misses and unsafe behaviors/conditions. Firstly, this paper researched deeply on the relationship and differentiation among incident, accident, near‐miss and unsafe behavior/condition. And the methodology of data collection about subway construction incident was represented. Secondly, Microsoft Access 2007 was employed as the software platform and each part of SCID was devised. Then the organization structure of SCID implementation was constructed from three aspects of surveillance, research and implementation, for the sake of a better effect. Finally, a case example to use the SCID for safety management in subway construction was expatiated. This study can fill a gap in the safety management of subway construction and will be contributive to safety risk analysis, as a qualitative tool in identifying relevant precursor scenarios or as a quantitative tool in estimating safety management.

Select this Article		Effects of Production Control Strategy and Duration Variance on Productivity and Work in Process ‐ A Simulation‐Based Investigation Kiarash Hajifathalian, Brad W. Wambeke, Min Liu, and Simon M. Hsiang Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000517 Posted ahead of print 8 December 2011 Full Text: \| Download PDF
	+ -	Show Abstract Improving productivity and reducing work in process (WIP) are two activities that can improve project performance, but are often difficult to accomplish. The construction process is complex and consists of a large number of interdependent and sequential tasks. Construction activities are simulated as serial production lines (SPLs) using STROBOSCOPE to investigate the effects that different production control strategies (push/pull and balanced/unbalanced) have on productivity and WIP. The sensitivity to task duration variance is also examined for the different working strategies. The simulation results are used to compare the models based on their performance. Results show that in presence of duration variance, push strategies result in higher productivity, while pull strategies result in lower amounts of WIP. Pull strategies are more sensitive to the presence of duration variance. It is also shown that WIP is a function of the coefficient of variance. The results of simulations are used to compare the tradeoffs between strategies. The findings will help construction managers to better understand the effects of working strategies and conditions to decide which production control strategy is best suited for their needs.

Select this Article		The Impact of Public Policy and Societal Risk Perception on U.S. Civilian Nuclear Power Plant Construction Timothy R. B. Taylor, David N. Ford, and Kenneth F. Reinschmidt Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000516 Posted ahead of print 8 December 2011 Full Text: \| Download PDF
	+ -	Show Abstract Due to increasing U.S. energy demand, the Nuclear Regulatory Commission is currently reviewing permit applications for 26 new nuclear power reactors. However, the previous generation of U.S. civilian nuclear plant construction experienced significant cost and schedule overruns. Previous research identified “regulatory ratcheting” (continuous, retroactive change in nuclear plant regulations) as one of the primary causes of this poor performance. Regulatory ratcheting was enabled by the nuclear industry's two‐step permitting and licensing process for civilian power plant construction (10 CFR Part 50) which allowed society's perception of the risks associated with nuclear plant operation to impact nuclear plant construction. How will public policy and societal risk perception affect the next generation of U.S. civilian nuclear plant construction? This question is investigated using a dynamic simulation model of the public policy and social feedback processes that impact U.S. nuclear plant construction. The research reveals that proposed strategies to address public policy and societal issues, such as a new nuclear regulatory process and smaller, less expensive reactors, may not prevent cost and schedule overruns on the planned next generation of nuclear plants. Results point to the critical role societal perceptions of nuclear power risk play in nuclear construction project success.

Select this Article		Greenhouse Gas Emissions from Onsite Equipment Usage in Road Construction Byungil Kim, Hyounkyu Lee, Hyungbae Park, and Hyoungkwan Kim Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000515 Posted ahead of print 7 December 2011 Full Text: \| Download PDF
	+ -	Show Abstract Greenhouse gas (GHG) emissions from onsite equipment usage have not been fully investigated despite their high reduction potential. This study presents a comparative analysis on the generation of GHGs by various equipment types used in different construction activities. Twenty‐four cases involving a typical road construction project in Korea were selected for comparison. GHG emissions from onsite equipment usage for different activities were estimated using final design documents, which fully defined the project for construction. This study also provided the expected ranges of such emissions according to equipment productivity related to site conditions of good, fair, and poor. For the major activities that produced most of the GHG emissions from onsite equipment, the value was estimated to be in the range of 256.52∼376.70 tCO₂e, with 282.17 tCO₂e for fair site conditions. A focus group interview (FGI) was conducted to identify guidelines that can be applied to improve equipment productivity to reduce GHG emissions. The proper selection of equipment and its components to deal with specific site conditions was one of the fundamental reduction methods derived through the FGI. These study results can be used to reduce GHG emissions from onsite equipment usage.

Select this Article		A Fuzzy Enabled Hybrid Genetic Algorithm‐Particle Swarm Optimization Approach to Solve Time‐Cost‐Resource Optimization (TCRO) Problems in Construction Project Planning Baabak Ashuri, M. ASCE and Mehdi Tavakolan, S. M. ASCE Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000513 Posted ahead of print 24 November 2011 Full Text: \| Download PDF
	+ -	Show Abstract One of the most challenging tasks of a construction project planner is to simultaneously minimize the total project cost and total project duration while considering issues related to optimal resource allocation and resource leveling. Therefore, project planners face complicated multivariate, Time‐Cost‐Resource Optimization (TCRO) problems that require time‐cost‐resource tradeoff analysis. The Hybrid Genetic Algorithm‐Particle Swarm Optimization approach is presented to solve complex, TCRO problems in construction project planning. The proposed approach uses the fuzzy set theory to characterize uncertainty about the input data (i.e., time, cost, and resources required to perform an activity) in this hybrid approach. The proposed fuzzy enabled Hybrid Genetic Algorithm‐Particle Swarm Optimization approach is applied to solve two optimization problems, which are found in the construction project planning literature. It is shown that the proposed fuzzy enabled Hybrid Genetic Algorithm‐Particle Swarm Optimization approach is superior than existing optimization algorithms to find better project schedule solutions with less total project cost, less total project duration, and less total variations of resource allocation. The results also show that the proposed approach is faster than existing methods in processing time for solving complex TCRO problems in construction project planning.

Select this Article		Solving the Least‐Cost Route Cut and Fill Sequencing Problem Using Particle Swarm Khaled Nassar and Ossama Hosny Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000512 Posted ahead of print 23 November 2011 Full Text: \| Download PDF
	+ -	Show Abstract Several researchers have attempted to formulate and solve different classes of the earthwork allocation problem. Linear programming (LP) and integer programming (IP) techniques have traditionally been applied to minimize transportation costs and mass haul distances associated with earthwork processes. However, typical formulations of the earthwork allocation problem do not consider the sequence of equipment movement and are, therefore, limited in their ability to establish a practical and workable hauling plan. A more complex problem, which is formulated and solved in this research, is the Least‐Cost Route Cut and Fill Problem (LCRCFP). The main objective of the LCRCFP is to determine the specific route to be traveled and the quantities of soil that construction equipment must haul to meet the desired grade while minimizing the total distance traveled. In this research, the LCRCFP was formulated as a mixed binary optimization problem and solved using a traditional Branch and Bound method and a Particle Swarm Optimization (PSO) technique. Accordingly, this solution can provide efficient and practical hauling plans for construction sites. Furthermore, a linear variation of the problem, which is common for linear roadwork or utility construction, was also formulated and solved. Extensive computational results are reported for several randomly generated instances of the LCRCFP. Realistic problems can be effectively solved using the PSO. Thus, the derived plan can be used in mapping and path‐planning and by onsite engineers. It can also be used for the deployment of unmanned construction equipment in autonomous vehicle control systems.

Select this Article		Performance of Temporary Rumble Strips at the Edge of Highway Construction Zones Tarek Elghamrawy, Khaled El‐Rayes, Liang Liu, and Ibrahim Odeh Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000511 Posted ahead of print 19 November 2011 Full Text: \| Download PDF
	+ -	Show Abstract This paper presents the results of field experiments conducted to evaluate the performance of temporary rumble strips at the edge of work zones as a new safety measure to alert inattentive drivers from encroaching into the work area in a similar way that permanent rumble strips are used. The two main objectives of these experiments are to (a) analyze and compare the effectiveness of various layouts of temporary rumble strips; and (b) provide practical recommendations to improve the design and layout of temporary rumble strips. The experiments evaluated the impact of five parameters on the effectiveness of temporary rumble strips and their generated sound levels, including: (1) rumble strip type; (2) number of strips per set; (3) strip spacing; (4) vehicle type; and (5) vehicle speed. A total of 162 different combinations of these parameters were tested to evaluate their individual and collective impact on the effectiveness of temporary rumble strips. The findings of this study show that temporary rumble strips at the edge of work zones generate adequate sound levels to alert inattentive drivers. The results of the experiments also show that the effectiveness of temporary rumble strips can be improved by (a) increasing the number of strips per set as practically as feasible; and (b) utilizing temporary rumble strips with larger widths.

Select this Article		Compaction Quality Control of Earth‐Rock Dam Construction Using Real‐Time Field Operation Data Donghai Liu, Jing Sun, Denghua Zhong, and Lingguang Song Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000510 Posted ahead of print 18 November 2011 Full Text: \| Download PDF
	+ -	Show Abstract Compaction quality is critical to the stability and durability of earth‐rock dams. The traditional quality inspection method relies primarily on testing randomly sampled spots of a job site, which may cause unreliable representation of the compaction quality of the entire work and lead to delays not only in performing the construction work but also in identifying and rectifying quality issues. We developed a quality‐inspection process of monitoring compaction operations of earth‐rock dam construction in real time, and we established a multiple regression model to predict compaction quality using independent variable data obtained from the real‐time quality‐monitoring system. These independent variables include compaction operation parameters (i.e., compaction passes, roller velocity, vibration status, and pavement thickness) and earth‐rock aggregate's moisture content and gradation. Furthermore, using the Kriging interpolation procedure, the compactness at any point of a work area can be estimated, and, in addition, the overall passing rate and the spatial uniformity of compaction quality of the work area can be analyzed. The case study of the NZD Dam project demonstrates the effectiveness and feasibility of the proposed method. It not only makes possible the evaluation of compaction quality covering 100% of the work area, thus reducing the uncertainty of quality inspection associated with random spot tests, but also enables timely feedback for quality control and improvement of earth‐rock dam construction.

Select this Article		Building Information Modelling Based Analysis to Minimize Waste Rate of Structural Reinforcement Atul Porwal and Kasun N. Hewage Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000508 Posted ahead of print 4 November 2011 Full Text: \| Download PDF
	+ -	Show Abstract Building Information Modeling (BIM) is an emerging tool in architecture/ engineering/ construction (A/E/C) industry that is used to design, document, and enhance communication among all the project stakeholders. Trim loss of rebar can be minimized with the use of discrete bars. In order to achieve this goal, a model to analyse reinforced concrete structure with 1D cutting waste optimization technique, integrated with BIM, is proposed. BIM is selected as the hub in communicating project information among diverse design teams. This process permits project teams to utilize BIM models to simulate architectural and structural design requirements, and compare results speedily, to make necessary changes in the designs to minimize rebar waste. The BIM rebar optimization analysis approach also supports cost effective decision making during the design process. The proposed approach was validated with a two storied reinforced concrete structure, and the results indicated a high potential for budgetary savings. The proposed approach is also applicable for complex reinforced concrete construction projects, with repeated structural elements, and cost saving increases with the increase in the diameter of rebar.

Select this Article		Modeling Correlations in Rail Line Construction Yvonne Moret and Herbert H. Einstein Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000507 Posted ahead of print 4 November 2011 Full Text: \| Download PDF
	+ -	Show Abstract The total construction cost and time of projects are often overrun. It is known that when positive correlations between costs are disregarded, the range of possible total construction costs is underestimated. A model is needed to estimate the impact of correlations on the probability distributions of total cost and total time. We identified four cost‐cost and one cost‐time correlations in the construction of rail lines, two of which we investigated in detail using a model applicable to the construction of any networked system. This paper presents the theoretical background of our model, the correlations occurring in rail line construction, and the analysis of the impact of such correlations in two case studies including several scenarios and one sensitivity analysis. The results clearly show that the standard deviation of the total cost increases with the magnitude of the correlation and, most importantly, it dramatically increases with the number of costs that are correlated; it also depends on the type of correlation matrix. Correlation between costs must be modeled to capture the wide range of the possible total cost, otherwise the total construction cost of projects will continue being significantly underestimated.

Select this Article		Experience in Expert Estimation of Probabilities and Correlations for Rail Line Construction Yvonne Moret and Herbert H. Einstein Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000505 Posted ahead of print 3 November 2011 Full Text: \| Download PDF
	+ -	Show Abstract To counteract cost escalation and delays in infrastructure construction, we have developed an estimation model that simulates project uncertainty with probability distributions, correlations and disruptive events. In the application to a new rail line project, three model inputs were not available from the designers: time distributions, cost correlations, and probability of occurrence and cost/time impacts of disruptive events. We asked experts in the field of tunnel‐, viaduct‐ and earthwork construction to estimate the unavailable information. This paper presents a brief overview of biases that occur when experts estimate probabilities, the calibration steps taken to prevent the experts from being affected by such biases, example questions from the questionnaire, followed by an in‐depth discussion of findings. Unexpectedly, the experts followed radically different estimation techniques: the tunnel expert recalled values from past projects, the viaduct expert calculated the required values, while the earthwork expert estimated the mode value and from it the extreme values. Depending on estimation technique, a bias influences or cannot influence an expert. It was also observed that experts not familiar with probability theory encountered major difficulties in correlation estimation despite concept explanation and visualization. Thus, for a successful correlation estimation it is paramount that the expert be acquainted with probability theory besides being knowledgeable in her/his field.

Select this Article		Safety Risk Quantification for High Performance Sustainable Building Construction Katherine S. Dewlaney, Matthew R. Hallowell, and Bernard R. Fortunato, III Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000504 Posted ahead of print 26 October 2011 Full Text: \| Download PDF
	+ -	Show Abstract A recent study found that LEED certified buildings have a recordable injury rate that is 9% higher than traditional, non‐LEED buildings. A follow‐up study showed that there are distinct aspects of the design elements and means and methods of construction used to achieve LEED certification that have negative impacts on worker safety. The research described in this paper builds on previous knowledge by quantifying the percent increase in base‐level safety risk resulting from the design strategies and construction methods implemented to earn specific LEED credits. A total of 26 interviews and 11 validation interviews were conducted with designers and contractors who had completed an average of 4 LEED projects, 100 traditional projects, in their average of 18 years of experience in the architecture, engineering, and construction industry. The results indicate that design elements and means and methods of construction implemented to achieve 12 of the 49 LEED credits increase the frequency of injuries or exposure to known, high risk environments. The most significant impacts are a 36% increase in lacerations, strains and sprains from recycling construction materials; a 24% increase in falls to lower level during roof work because of the installation of on‐site renewable energy (e.g., PV panels); a 19% increase in eye strain when installing reflective roof membranes; and a 14% increase in exposure to harmful substances when installing innovative wastewater technologies. These results can be used to understand the safety impacts of sustainable building design, will enhance designer awareness, and help contractors to better prioritize safety resources.

Select this Article		Performance Dashboard for a Pharmaceutical Project Benchmarking Program Sung‐Joon Suk, Bon‐Gang Hwang, Jiukun Dai, Carlos H. Caldas, and Stephen P. Mulva Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000503 Posted ahead of print 26 October 2011 Full Text: \| Download PDF
	+ -	Show Abstract Performance measurement is essential to controlling and improving capital projects. Increasingly, industry sectors demand an industry‐specific performance measurement system because their unique processes can result in significant differences in performance outcomes. This paper describes the development of a performance dashboard for a pharmaceutical project benchmarking program. The proposed approach adopts a relative comparison method and uses weighted key performance metrics (KPMs) to compare project performance. The dashboard generates an overall performance score both at the project level and at the company level, which are illustrated in tabular and graphical formats. The dashboard provides flexibility for comparing the performance of projects even when the project types or KPMs measured are different. Although the study focuses on a performance dashboard for pharmaceutical industry projects, the dashboard development process described in this paper can be applied to other industry projects.

Select this Article		Life Cycle Cost Analysis on Glass Type of High‐Rise Buildings for Increasing Energy Efficiency and Reducing CO₂ Emissions in Korea Chijoo Lee, Taehoon Hong, Ghang Lee, and Jiyoung Jeong Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000502 Posted ahead of print 24 October 2011 Full Text: \| Download PDF
	+ -	Show Abstract As high‐rise buildings become taller, their building area and elevation area also increase, consequently increasing their yearly energy consumption. Especially when glass is used for a building's exterior, energy efficiency has become an even more important issue. In this study, life cycle cost (LCC) about the exterior glass of high‐rise buildings was analyzed from the perspective of energy efficiency and CO₂ emissions. First, LCC was analyzed according to change in the selected types of glass. Reflective + Low‐E (Type 1), Double Low‐E + Argon (Type 2), and Triple Low‐E + Argon (Type 3), which satisfy green building certification criteria and were used in the past for high‐rise buildings in Korea, were selected as the exterior glass types. These types of exterior glass were applied to a case building and compared with the Low‐E glass that was the existing glass type of a case building. The economic benefit of selected glasses for 40 years was greater in the order of Type 1, Type 3, and Type 2 compared to the existing glass. Second, these types of glass were applied to each orientation of the building. A change in the glass by building orientation show that in the east, west and north, Type 1 was most economical, while Type 3 was most economical in the south. The results of this study will contribute to the improvement of energy efficiency, CO₂ emission reduction, and cost‐efficiency of future high‐rise buildings.

Select this Article		Factors Affecting Construction Labor Productivity in Kuwait Abdulaziz M. Jarkas, Ph.D., P.Eng. and Camille G. Bitar, P.Eng. Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000501 Posted ahead of print 20 October 2011 Full Text: \| Download PDF
	+ -	Show Abstract Construction labor productivity has become such a “buzz” word and one of the most frequently researched topics. In most countries, labor cost comprises 30 to 50% of the overall project's cost, and thus is regarded as a true reflection of the economic success of the operation. There are many challenges facing the construction industry in the State of Kuwait, but one of the most important is low productivity. The objective of this research, therefore, is to identify and rank the relative importance of factors perceived to affect labor productivity on construction sites in the State. To achieve this objective, a statistically representative sample of Contractors was invited to participate in a structured questionnaire survey, comprising forty five productivity factors, classified under the following four primary groups: (a) management; (b) technological; (c) human/labor; and (d) external. Among the factors explored, the subsequent ten are discerned to be the most significant in their effects on labor productivity: (1) clarity of technical specifications; (2) the extent of variation/change orders during execution; (3) coordination level among design disciplines; (4) lack of labor supervision; (5) proportion of work subcontracted; (6) design complexity level; (7) lack of incentive scheme; (8) lack of construction manager's leadership; (9) stringent inspection by the “Engineer”; and (10) delay in responding to “Requests For Information” (RFI). The results obtained fill a gap in knowledge of factors affecting labor productivity in Kuwait, which can be used by industry practitioners to develop a wider and deeper perspective of the factors influencing the efficiency of operatives, and provide guidance to construction managers for efficient utilization of the labor force, hence assist in achieving a reasonable level of competitiveness and cost effective operation.

Select this Article		Safe Design Suggestions for Vegetated Roofs Michael Behm Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000500 Posted ahead of print 18 October 2011 Full Text: \| Download PDF
	+ -	Show Abstract Rooftop vegetation is becoming increasingly popular due to environmental benefits and its ability to earn green building certification credits. With the exception of one international guideline, there is little mention of worker safety and health in vegetated roof codes and literature. Observations and field investigations of nineteen vegetated roofs in the United States revealed unsafe access for workers and equipment, a lack of fall protection measures, and other site specific hazards. Design for safety strategies and the integration of life cycle safety thinking with green building credits systems are preferred methods to reduce risk to workers on vegetated roofs. Design suggestions have been developed to add to the body of knowledge. The findings complement several National Institute for Occupational Safety and Health (NIOSH) Construction and Prevention through Design (PtD) goals, are congruent with NIOSH's Safe Green Jobs initiative. Organizations who install and maintain vegetated roofs can utilize the findings to understand hazards, take precautions, and incorporate safety into their bids.

Select this Article		Diffusion of Safety Innovations in the Construction Industry Behzad Esmaeili and Matthew R. Hallowell Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000499 Posted ahead of print 18 October 2011 Full Text: \| Download PDF
	+ -	Show Abstract Safety performance in the construction industry has improved significantly in the past four decades. This improvement has been attributed in part to the increased implementation of injury prevention strategies. Though the relative effectiveness of these strategies has been studied in previous research, there has been no attempt to evaluate their diffusion. In order to address this gap in knowledge, twelve highly effective administrative safety innovations were identified in literature and fifty eight firms were interviewed to investigate their adoption rate. The diffusion patterns of the identified safety innovations were explored using four common innovation diffusion models: the internal, external, Bass, and Gompetz. The findings indicate that the internal and Bass models have the highest explanatory power and that internal factors are the most influential factors in adoption of safety innovations by construction firms. It was also found that project‐specific safety training (91%), frequent worksite inspections (91%), and safety and health orientation and training (90%) are the three most commonly‐adopted safety innovations and employment of a site safety manager (62%), subcontractor selection and management (64%), and substance abuse programs (69%) were the three innovations most infrequently implemented. The implication of the findings is that the construction industry has now reached saturation with respect to traditional injury prevention strategies and new safety innovations are needed.

Select this Article		Measurement and Antecedents of Cooperation in Construction Aaron M. Anvuur and Mohan M. Kumaraswamy, M. ASCE Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000498 Posted ahead of print 18 October 2011 Full Text: \| Download PDF
	+ -	Show Abstract The cooperation construct in construction lacks conceptual‐definitional clarity. A multi‐dimensional model of cooperation is proposed in which the construct is conceptualized as comprising four related yet conceptually distinct behaviors: in‐role, extra‐role, compliance, and deference behavior. The construct validity of this model is assessed using confirmatory factor analysis and a sample of 140 professional managers in Hong Kong. Structural equation modeling is then used to test specific predictions linking the four cooperative behaviors with two extrinsic (incentives and sanctions) and intrinsic (intrinsic job satisfaction and legitimacy) job cognition variables. Findings confirm the convergent, discriminant, and nomological validity of the proposed model. Between them, the two intrinsic job cognition variables predict all four behavior dimensions: intrinsic job satisfaction predicts in‐role and extra‐role behaviors; and legitimacy predicts compliance and deference behaviors. In contrast, the influence of the extrinsic job cognition variables on cooperative behavior is imprecise and weaker. The research suggests that initiatives aimed at improving the level of cooperation in construction project settings should focus more attention on stimulating the internal motivations (enhancing ‘personal causality’) of project actors.

Select this Article		An Empirical Study to Investigate the Difficulties of Implementing Safety Practices in the Repair and Maintenance Sector: A Case of Hong Kong Carol. K. H. Hon, Albert P. C. Chan, and Michael C. H. Yam Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000497 Posted ahead of print 12 October 2011 Full Text: \| Download PDF
	+ -	Show Abstract Repair, maintenance, minor alteration and addition work (RMAA) has become more and more important in developed societies but its safety performance is also alarming. For example, RMAA works accounted for 53.2% of the total construction market of the Hong Kong Special Administrative Region (HKSAR) in 2007 and the percentage of RMAA accidents to all construction accidents in HKSAR increased considerably from 17.9% in 1998 to 50.1% in 2007. The RMAA sector has huge potential for safety improvement. This study aims to explore and evaluate the difficulties of implementing safety practices in RMAA work. Mixed methods approach was adopted. Semi‐structured interviews and a two‐round Delphi survey were conducted for data collection. Major difficulties identified include: limited safety resources for small and medium enterprises (SMEs); difficulty in changing the mindset of RMAA workers; and difficulty in performing safety supervision. These obstacles of implementing safety practices in RMAA sector, if successfully removed, can significantly improve safety performance of the RMAA sector as well as the whole construction industry.

Select this Article		Levels of Inter‐Organizational Trust in Construction Projects: Empirical Evidence Albertus Laan, Hans Voordijk, Niels Noorderhaven, and Geert Dewulf Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000495 Posted ahead of print 3 October 2011 Full Text: \| Download PDF
	+ -	Show Abstract Interorganizational trust is important, especially in an industry characterized by constantly changing combinations of organizations working on temporary projects, like the construction industry. However, we know little about the factors influencing trust in this setting. This study aims to begin to fill that gap, by studying trust in their counterpart as expressed by principals and contractors engaged in construction projects. Our findings show that the temporal embeddedness of the relationship (past and expected future relations) is strongly positively related to the level of trust. Moreover, we find that the tendering procedure used and the delivery system employed influence the level of trust of the contractor, but not that of the principal. We draw practical implications as well as suggestions for further research from these results.

Select this Article		Skip‐Lot Acceptance Sampling Plans for Highway Construction and Materials Nasir G. Gharaibeh, Litao Liu, and Sujay S. Wani Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000494 Posted ahead of print 30 September 2011 Full Text: \| Download PDF
	+ -	Show Abstract Current acceptance sampling plans for highway construction and materials require the sampling and testing of every individual lot (i.e., 100% of the lots are inspected). This approach is appropriate if the contractor is erratic. But, if the contractor is fairly consistent, skip‐lot sampling suggests that only a fraction of the lots need to be tested. This paper presents an algorithm for developing skip‐lot sampling plans for highway construction and materials acceptance. A skip‐lot acceptance sampling plan has been developed and compared to AASHTO's lot‐by‐lot acceptance plan. The analysis shows that skip‐lot sampling reduces the amount of acceptance sampling and testing when the contractor has a history of delivering high‐quality product. Rather than simply inspecting every lot, highway agencies can use skip‐lot sampling to develop knowledge‐based acceptance plans that entail less sampling and testing than currently required.

Select this Article		A Floor‐Level Construction Material Layout Planning Model Considering Actual Travel Path Moonseo Park, Youngjun Yang, Hyun‐Soo Lee, Sangwon Han, and Sae‐hyun Ji Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000493 Posted ahead of print 30 September 2011 Full Text: \| Download PDF
	+ -	Show Abstract Unnecessary material transportation accounts for a significant portion of non‐productive work. Previous research has paid much attention to site‐level transportation, but little attention to floor‐level transportation. This is because the distance of floor‐level material transportation is relatively small compared to that at a site level. With an increase in the size, height and complexity of building projects, the impact of floor‐level transportation on worker productivity and project performance has significantly increased. This paper introduces a floor‐level construction material layout planning model which can represent 1) various shapes of an installation task and 2) actual travel distance, which are necessary for realistic representation of floor‐level material transportation. Applied to a high‐rise residential apartment project, the model has proven to be effective in terms of minimizing travel distance and travel time. Based on this finding, it is concluded that the model has great potential as an aid for reducing non‐productive work, and ultimately enhancing project performance.

Select this Article		Construction Resource Allocation and Leveling Using a Threshold Accepting Based Hyperheuristic Algorithm Georgios K. Koulinas and Konstantinos P. Anagnostopoulos Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000492 Posted ahead of print 26 September 2011 Full Text: \| Download PDF
	+ -	Show Abstract In this study we propose a threshold accepting based hyperheuristic for solving in a single run both the resource‐constrained project scheduling problem or resource allocation, and the resource leveling problem. Having their roots in the field of artificial intelligence, hyperheuristics operate in the “low‐level” heuristics domain rather than in the solutions domain. The hyperheuristic has been implemented within a commercial project management software package. Low‐level heuristics operate on the solution domain defined by the priority values that the software uses for resource allocation. A case example from the literature and computational experiments on randomly generated projects demonstrate that the hyperheuristic achieves good performance in a timely manner, improving the results provided by the software.

Select this Article		Structured Idea Creation for Improving the Value of Construction Design Sungwoo Moon, A. M. ASCE, Chideok Ha, Aff. M. ASCE, and Jinkook Yang, Aff. M. ASCE Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000491 Posted ahead of print 16 September 2011 Full Text: \| Download PDF
	+ -	Show Abstract Value Engineering (VE) is an effort to increase the value of a system through a creative and organized approach. Idea generation is the most important part in a VE job plan. Although the experts in a VE team can evaluate multiple alternatives that can replace the original idea, idea generation is usually based on their knowledge and experience. A structured method will help to consider different functional perspectives and to create inventive ideas that could have been missed otherwise. This paper presents a Construction Value Engineering‐Inventive Idea Support (CVE‐IIS) tool for structured idea generation in construction VE. In this study, previous VE reports were analyzed to understand the pattern of proposed ideas in highway‐construction design. These ideas were categorized according to the rules of Advanced Systematic Inventive Thinking (ASIT) to establish an idea breakdown structure (IBS). The IBS was then used to support the generation of construction ideas using idea‐generation worksheets. A case study demonstrated that the CVE‐IIS can help improve the value of design functions by improving performance.

Select this Article		A Capability Model to Improve Infrastructure Asset Performance Eric G. Too Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000489 Posted ahead of print 16 September 2011 Full Text: \| Download PDF
	+ -	Show Abstract Infrastructure organizations are operating in an increasingly challenging business environment as a result of globalization, privatization and deregulation. In an external business environment that is constantly changing, extant literature on strategic management advocates the need to focus on factors internal to the organization such as resources and capabilities to sustain their performance. Specifically, they need to develop dynamic capabilities in order to survive and prosper under conditions of change. The aim of this paper is to explore the dynamic capabilities needed in the management of transport infrastructure assets by using a multiple case study research strategy. It identified five dynamic capabilities namely stakeholder connectivity, cross‐functional, relational, technology absorptive and integrated information capability as central to strategic infrastructure asset management. The findings culminated in the development of a capability model to improve the performance of infrastructure assets in an increasingly dynamic business environment.

Select this Article		Contractor Selection Using Multi Criteria Decision Making Methods J. R. San Cristóbal Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000488 Posted ahead of print 16 September 2011 Full Text: \| Download PDF
	+ -	Show Abstract Contractors play a vital role in the overall performance of a project. Selecting the right contractor for the right project is the most crucial challenge for any construction client. Numerous and often conflicting objectives and alternatives such as tender price, completion date, experience, etc., need to be considered. Recently, to assist owners in making decisions, there has been a trend away from a “lowest‐price wins” principle and subjective judgement, to a multi‐criteria selection approach in the selection of contractors for construction projects. In the autonomous region of Cantabria, in the north of Spain, increased project complexity and higher requirements have recently demanded the use of multi‐criteria decision making methods for contractor selection. With this aim, two multi‐criteria decision methods, the TOPSIS and VIKOR methods are applied to the selection of a contractor for the road building project “La Braguía” undertaken during 2002. The results show that one of the contractors is the highest ranked by both methods. Being the highest ranked alternative by the TOPSIS method means that this contractor is the best in terms of the ranking index. In addition, being the highest ranked alternative by the VIKOR method means that it is the closest to the ideal solution.

Select this Article		Analysis of the Higher Order Partial Correlation between CII Best Practices and Performance of the Design Phase in Fast Track Industrial Projects Abhijeet S. Deshpande, Ossama M. Salem, and Richard A. Miller Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000487 Posted ahead of print 16 September 2011 Full Text: \| Download PDF
	+ -	Show Abstract The fast track project delivery strategy is designed to leverage the ability to execute the design, procurement and construction phases simultaneously to substantially reduce the overall project duration. The successful execution of the design phase in fast track projects is especially challenging because the concurrent execution of design and construction interferes with the inherently iterative nature of the design process. In this research, it was hypothesized that there is a correlation between the use of some of the CII Best practices and the performance of design phase in fast track projects. The analysis of the performance of design phase in thirty one fast track projects revealed a statistically significant correlation between performance of the design phase and front end planning, alignment, constructability, change management. The results of quantitative analysis are supported by qualitative analysis of data, opinion of experts from industry and academia. The projects analyzed in the study were executed by CII member companies with experience and knowledge of using the best practices effectively.

Select this Article		Stock‐Flow Model for Forecasting Manpower Supply Chun‐pong Sing, P. E. D. Love, and C. M. Tam Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000485 Posted ahead of print 5 September 2011 Full Text: \| Download PDF
	+ -	Show Abstract Forecasting the supply of labor within the construction industry is pivotal to long‐term economic growth. A labor supply model using a stock‐flow approach is developed for use in the construction industry. The model is tested using Hong Kong census statistics and data derived from interviews with 3000 randomly selected construction workers. The findings were modeled using a stock‐flow model, which enabled the determination of future aging distribution trends and workforce supply for specific trade types. The developed stock‐flow model can be effectively utilized in countries where registration schemes for construction workers are in use.

Select this Article		Eco‐Efficiency of Construction Materials: A Data Envelopment Analysis Omer Tatari and Murat Kucukvar Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000484 Posted ahead of print 3 September 2011 Full Text: \| Download PDF
	+ -	Show Abstract Sustainability assessment tools are critical in the process of achieving sustainable development. Eco‐efficiency has emerged as a practical concept that combines environmental and economic performance indicators to measure the sustainability performance of different product alternatives. In this paper, an analytical tool that can be used to assess the eco‐efficiency of construction materials is developed. This tool evaluates the eco‐efficiency of construction materials using data envelopment analysis; a linear programming based mathematical approach. Life cycle assessment and life cycle cost are utilized to derive the eco‐efficiency ratios, and data envelopment analysis is used to rank material alternatives. Developed mathematical models are assessed by selecting the most eco‐efficient exterior wall finish for a building. Percent improvement analysis was carried out to investigate target environmental impact categories that need more reduction to reach 100% eco‐efficiency. Through this study, our goal is to show that DEA‐based eco‐efficiency assessment model could be used to evaluate alternative construction materials and offer vital guidance for decision makers during material selection.

Select this Article		Heuristic Method for Satisfying Both Deadlines and Resource Constraints Tarek Hegazy, M. ASCE and Wail Menesi, S. M. ASCE Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000483 Posted ahead of print 3 September 2011 Full Text: \| Download PDF
	+ -	Show Abstract Project deadline and resource limits are practical constraints that co‐exist in most projects. While heuristic methods for Constrained Resource Scheduling (CRS) have become mainstream in commercial scheduling software, no commercial software includes any Time‐Cost Trade‐Off (TCT) heuristic to help meet deadline, let alone any procedure to resolve both deadline and resource constraints. This paper, therefore, introduces a practical heuristic method to meet both deadline and resource limits. The proposed method basically uses cycles of crashing for lowest‐cost critical activities (i.e., stepwise TCT process) and resolves any resource overallocation (i.e., CRS) within each TCT cycle. This intertwined approach is logical, fast, and provides a set of feasible project durations that do not violate resource limits. To facilitate its practical use, the proposed method has been programmed as an add‐in tool to Microsoft Project software. The paper discusses several case studies that prove the practicality and usefulness of the proposed approach to both researchers and professionals and provides a comparison of results with other literature efforts.

Select this Article		The Impact of Machine‐Failure Costs on Equipment Replacement Policies: A Tunneling Company Case Study Luis F. Alarcón, Andrés Rodríguez, and Claudio Mourgues Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000480 Posted ahead of print 2 September 2011 Full Text: \| Download PDF
	+ -	Show Abstract For those construction companies engaged in projects where production is controlled by equipment availability, with tunneling being maybe the most extreme example, equipment replacement policies effect not just the cost of a machine but have a decisive impact on overall project cost and achieved profit. Although equipment replacement models described in the literature suggest that the consequential costs of equipment failure are significant and should be considered in replacement decisions, most fail to explicitly include consequential costs or fail to provide methods to calculate the consequential cost in complex systems. This lack of consequential cost in a model seriously diminishes the effectiveness of a company's equipment replacement policies and the company's ability to earn a project. This work describes a case study that used simulation to quantify the consequential costs of equipment availability for a company engaged in tunnel‐construction. The study includes the simulation of activities of the drill and blast method for five tunnel types. The simulation proved to be very valuable when seeking to evaluate consequential costs. The results indicate that consequential costs are very relevant to the replacement decision of the most expensive equipment. Also, the results show a significant impact of the consequential costs on the company's equipment replacement policies. Therefore, changes in existing policies to consider consequential costs have the potential of providing important future benefits for such companies.

Select this Article		Early Cost Estimating of Road Tunnel Construction Using Neural Networks K. Petroutsatou, E. Georgopoulos, S. Lambropoulos, and J. P. Pantouvakis Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000479 Posted ahead of print 2 September 2011 Full Text: \| Download PDF
	+ -	Show Abstract Road tunnel construction is subject to underground uncertainties and risks and, as such, it is difficult to predict the final construction cost, especially at the conception phase where issues are evaluated and important design decisions are made. A system assisting in the early cost estimation of road tunnels would, therefore, be of great value as it would allow the quick costing of alternative and more economical solutions. The development of such an early cost estimation system is discussed in this paper. First, the basic parameters (geological, geometrical and work quantities related) affecting temporary and permanent support and final construction cost are determined. After that, appropriate real‐world data derived from the analysis of 33 twin tunnels of 46 km total length constructed for the Egnatia Motorway in Northern Greece from 1998 to 2004 and related to work quantities is collected and normalized. Appropriate price lists are then applied to calculate the costs; subsequently, cost estimating models are developed using two types of neural networks: the multilayer feed‐forward network and the general regression neural network. Finally, these models are compared against real quantities and costs for accuracy and robustness. The main conclusion is that the models developed are fit for their purpose and may lead to fairly accurate work quantities and cost estimates of road tunnels.

Select this Article		Post Occupancy Energy Consumption Survey of Arizona's LEED New Construction Population Dixon Oates, M.S. and Kenneth T. Sullivan, Ph.D., MBA Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000478 Posted ahead of print 2 September 2011 Full Text: \| Download PDF
	+ -	Show Abstract Existing literature has not provided conclusive performance results for green building energy efficiency. Existing studies produced debated conclusions and failed to represent a geographic concentration of structures from hot and dry climates. This technical paper examines 47 percent of Arizona's 53 building Leadership in Energy and Environmental Design for New Construction (LEED NC) building population in an effort to determine if Arizona's LEED NC buildings achieve expected energy performance, how they compare to the existing building population and if either system or managerial variables demonstrate efficiency correlations. Data collection efforts were successful for all desired deliverables. Analysis of the LEED NC sample returned mixed results. On average, Arizona's LEED NC medium energy intense (MEI) buildings performed better than the national average yet worse than buildings located in similar climates. Certain LEED NC MEI building types did demonstrate greater efficiencies than the corresponding CBECS population. Arizona's high energy intense (HEI) structures performed considerably lower than national and similar climate averages. The LEED NC sample also underperformed both the design and baseline energy use simulations. Energy consumption correlation analysis returned very few statistically significant results The study's results demonstrate to industry practitioners and researchers that the LEED NC rating system's energy strategies fail to meet modeled efficiencies, thereby highlighting a need for ongoing scrutiny and diligence when measuring sustainability and efficiency within Arizona's built environment.

Select this Article		Causes and Penalties of Variation ‐ A Case Study of a Precast Concrete Slab Production Facility Chao Wang, Min Liu, Simon M. Hsiang, and Michael L. Leming Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000475 Posted ahead of print 24 August 2011 Full Text: \| Download PDF
	+ -	Show Abstract Concrete precast plants require strict control over and adherence to the timing and sequence of operations. Variation for this research is divided into the variation in task starting time (the difference between the planned and the actual starting time) and the variation in task duration (the difference between the planned and the actual task duration). This study determined causes of variation in task starting time and duration of precast concrete slab production tasks. It also identified penalties associated with not reducing variation, which include an increase in project duration, Work in Progress (WIP) and cost and a decrease in labor productivity. Additionally, two execution policies (keeping laborers waiting before preconditions are ready and keeping laborers busy) in the face of variation were compared using STROBOSCOPE simulation techniques. It was found that simply keeping workers busy is insufficient for managing variation. Management effort should be devoted to eliminate causes of variation in the planning stage to make reliable work plan. The results will help prefabricators to understand causes and penalties of variation, which is the starting point of attacking and reducing it. Although this study is based on a concrete slab production facility, this research can have a broader impact on the construction industry as the research method and simulation models developed in this study can be generalized to apply to other fabrication processes as well.

Select this Article		Erratum for “A Net Asset Value Based Concession Duration Model for BOT Contracts” by Min Wu, Geoffrey Q.P. Shen, and Liyin Shen Min Wu, Geoffrey Q. P. Shen, and Liyin Shen Journal of Construction Engineering and Management doi:http://dx.doi.org/ Posted ahead of print 20 August 2011 Full Text: \| Download PDF
		Abstract Unavailable

Select this Article		A GA‐Based Fuel‐Efficient Transfer Path Selection Model for Delivering Construction Materials Kyo‐Jin Koo and Sung‐Chul Park Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000473 Posted ahead of print 19 August 2011 Full Text: \| Download PDF
	+ -	Show Abstract Oil prices may continue to rise indefinitely until alternative fossil fuels or renewable energies are commercialized. In this sense, general contractors who have the responsibility of delivering construction materials should select an optimized alternative that needs the least oil among the various combinations of truck types of logistics companies, routes, and suppliers. In this context, the objective of this paper is to develop a genetic‐algorithm‐based fuel‐efficient transfer path selection model (GAFETPSM) for delivering construction materials with minimum fuel consumption. GAFETPSM considers the truck type, road type, and fuel efficiency variation by load as well as the constraints of capacity, number of trucks, and total load to be delivered. Finally, a case study showed that GAFETPSM is superior to the simulated‐annealing (SA)‐based model in terms of fuel consumption in delivering the same weight of construction materials. It is expected that GAFETPSM could contribute to reduce the carbon dioxide emission by using less oil.

Select this Article		Erratum for “Data Mining Framework to Optimize the Bid Selection Policy for Competitively Bid Highway Construction Projects” by W. Art Chaovalitwongse, Trefor P. Williams, Wanbin Wang, and Paveena Chaovalitwongse W. Art Chaovalitwongse, Trefor P. Williams, Wanbin Wang, and Paveena Chaovalitwongse Journal of Construction Engineering and Management doi:http://dx.doi.org/ Posted ahead of print 18 August 2011 Full Text: \| Download PDF
		Abstract Unavailable

Select this Article		Metodología para el Diagnóstico de la Sostenibilidad de Empresas de Servicios Públicos Holger Benavides Muñoz Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000470 Posted ahead of print 17 August 2011 Full Text: \| Download PDF
	+ -	Show Abstract A través de este trabajo se presenta una metodología que permite diagnosticar la sostenibilidad de una empresa de servicios públicos, con base en la evaluación técnica ‐mediante indicadores‐, que luego son agregados cuali ‐ cuantitativamente en un índice que reune las propiedades y características de la empresa; dicho valor, implícitamente compara los estados particulares de calidad y su equilibrio global deseado. El índice de sostenibilidad de empresas de servicio público — ISEM —, (ISA para abastecimientos de agua) es el resultado numérico, analíticamente trazable, de la combinación de una proposición convergente que asocia la interacción entre los aspectos: social, económico y ambiental. El proceso de agregación, en su componente cualitativo, requiere de la vinculación de experiencias y criterios participativos de expertos e involucrados en la gestión de este tipo de empresas, recopilados mediante entrevistas técnicas ‐ Delphi. La exactitud y veracidad del componente cuantitativo, en cambio, depende de los datos proporcionados por el equipo gestor o gerencial. La metodología ISEM, nace con el propósito de convertirse en una herramienta útil para la orientación en la planificación y toma de decisiones del grupo político, sujetos financieros, entes de auditoría técnica y el propio cuerpo director y gerencial de la empresa de servicio público, de una forma simplificada, potente y práctica. Asimismo, la presentacioón gráfica de los resultados del diagnóstico ISEM, exhibe su estructura constitutiva, facilita su desagregación para la identificación de patologías en la gestión y promueve la selección y priorización participativa de medidas correctoras.

Select this Article		Streamlining the Construction Productivity Improvement Process with the Proposed Role of a Construction Productivity Improvement Officer (CPIO) Upul Ranasinghe, Janaka Ruwanpura, and Xin Liu Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000469 Posted ahead of print 13 August 2011 Full Text: \| Download PDF
	+ -	Show Abstract Construction productivity improvement has become a key area of focus among academia and industry over the last decade, due to its strong potential in benefitting the construction industry. Despite its high impact on the construction industry, productivity improvement is still an area in which much research work needs to be done to explore its true potential in a practical industry context. Today's construction industry seems to adopt productivity improvement initiatives to gain a competitive edge in the global market place; however, systematization of these approaches is still an area of concern. This paper discusses a framework for the implementation of productivity improvement activities on a construction site, making the process more systematic, accountable and sustainable with the creation — of a dedicated position — the construction productivity improvement officer (CPIO) on construction sites.

Select this Article		Buscando un Modelo para la Innovación Sistemática en Empresas Constructoras (in Search of a Model for Systematic Innovation in Construction Companies) Eugenio Pellicer, Víctor Yepes, Christian L. Correa, and Luis F. Alarcón Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000468 Posted ahead of print 13 August 2011 Full Text: \| Download PDF
	+ -	Show Abstract Los motivos que impulsan a una empresa constructora a innovar, así como los procedimientos utilizados, no han sido suficientemente explorados hasta el momento en la literatura especializada. En general, la innovación en la construcción se realiza todavía con un enfoque informal que debería transformarse en un proceso más sistemático dentro de la gestión empresarial. La investigación descrita en el presente artículo pretende validar un modelo, establecido a partir de la metodología del estudio de caso, que explique el modo y las razones que impulsan la gestión de la innovación en una empresa constructora. El método de investigación empleado se basa en la revisión del estado del arte y la práctica y en el estudio de caso, constituyendo la unidad de análisis una empresa constructora de tamaño medio que tiene implantado un sistema de gestión de la innovación certificado mediante la norma UNE 166002. La investigación desarrollada por los autores durante los últimos cinco años ha permitido formular un conjunto de 18 proposiciones que definen un modelo explicativo de la gestión de la innovación. Este artículo reporta la validación del modelo, cuyos resultados corroboran plenamente 15 de las proposiciones planteadas. El proceso de validación detectó una percepción débil entre la estrategia empresarial y los resultados en innovación, y una relación media entre la adopción de sistemas normalizados de gestión de la innovación y el incremento de la competitividad, tanto a nivel de proyecto como de empresa. Las conclusiones del estudio se encuentran limitadas por la escasa experiencia acumulada en la normalización de estos sistemas, por lo que la refutación o mejora del modelo propuesto debe realizarse en el futuro con un mayor número de empresas, más maduras en la gestión de la innovación, y que dispongan de sistemas certificados.

Select this Article		Modeling Competitiveness Factors and Indexes for Construction Companies: Findings of Chile Francisco A. Orozco, Alfredo F. Serpell, Keith R. Molenaar, and Eric Forcael Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000462 Posted ahead of print 6 August 2011 Full Text: \| Download PDF
	+ -	Show Abstract Globalization and the highly competitive environment have led to an urgent need to create effective competitive strategies in order to survive. Therefore, companies require a better understanding about the interrelationships between the factors that determine competitiveness and indexes to measure it. Considering that strategic planning within the construction industry has had documented challenges, this research provides support for decision‐making associated with improving competitiveness. This paper first provides the critical variables that define the competitiveness of general contractors according to top managers for general contractors companies. Then, an interrelationship model has been proposed to describe how these variables are interrelated based on well‐known business models and other relationships found in the literature. The proposed model was evaluated using the Partial Least Squares path modeling technique. The results show that leadership has, in general, the strongest impact on the competitiveness indexes, which means that whatever the goal set by the construction company, close attention should be placed on leadership. The other factors, following leadership, that mostly affect the indexes were contract management and health and safety management. The results intend to support strategic planning in construction companies by helping managers to orient the company's efforts with those factors that contribute to the specific indexes that need improvement.

Select this Article		A Quantitative Method for Updating Cost Contingency throughout Project Execution Hua Xie, Simaan AbouRizk, and Junhao Zou Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000457 Posted ahead of print 30 July 2011 Full Text: \| Download PDF
	+ -	Show Abstract This paper presents a method for project cost contingency forecasting and updating, based on Value at Risk, at a certain confidence level during project execution. The method is applied and demonstrated through an ongoing tunnel construction project lasting for several years. The method makes use of newly available information as the project progresses, and daily cost and progress are analyzed and used as inputs for the quantitative model. The forecasts compare favorably with actual contingencies. The method provides opportunities to update contingencies at project milestones, and to allocate appropriate contingencies at different project phases. This is beneficial for major companies which run multiple projects lasting for years, allowing them to set appropriate contingencies on certain timelines and to improve resource utilization.

Select this Article		Observations on Bridge Performance during the Chilean Earthquake of 2010 Cliff Schexnayder, Dist. M. ASCE, Luís F. Alarcón, M. ASCE, Eduardo Delpiano Antillo, Bernardo Cifuentes Morales, and Mauricio Lopez Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000452 Posted ahead of print 30 July 2011 Full Text: \| Download PDF
	+ -	Show Abstract The joint U.S. State Department ‐ Chilean Fulbright Program sent Senior Specialists to Chile after the 2010 “Maule” earthquake to perform collaborative studies with faculty from Chile's main universities. The study described here found that concrete‐girder bridges built since 1995 without diaphragms and shear keys suffered extensive damage while older bridges designed and built with these features did not suffer as greatly from twisting or rotation about the vertical axis. Because of the steepness of embankment slopes many bridge abutments exhibited slumping. Concrete retaining walls and mechanically‐stabilized‐embankment walls were not damaged. Liquefaction induced pier settlements and lateral spreading impacted bridge performance in coastal regions.

Select this Article		Urban Sustainability Predictive Model Using GIS: Appraised Land Value versus LEED Sustainable Site Credits Kiyoung Son, Kunhee Choi, Young‐jun Park, and Paul Woods Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000449 Posted ahead of print 9 July 2011 Full Text: \| Download PDF
	+ -	Show Abstract Although many researchers have attempted to examine the value‐added advantages of adopting LEED standards for sustainable design projects, quantitative research into its impact on the appraised unit value of land has been fairly limited. The objective of this study is to develop a quantifying model that predicts the unit value of unimproved lands by analyzing the interdependency between the adoption of three LEED Sustainable Site Credits (LEED SSCs) and the appraised unit value of unimproved lands. Using a GIS mapping technique, a set of LEED SSC data were created and transformed for normality. A multiple linear regression analysis was then performed to develop the predictive model with a time and location adjustment factor in order to analyze how the appraised value of land was affected by the presence of three LEED SSCs. The analysis indicates that adapting projects to meet acceptance standards for LEED SSCs has a significant positive impact on the appraised unit value of improved lands. The findings of this study will help decision‐makers frame sustainable real‐estate development projects that consider LEED SSCs.

Select this Article		LEED Public Transportation Accessibility and Its Economic Implications Kunhee Choi, Kiyoung Son, Young‐jun Park, and Paul Woods Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000441 Posted ahead of print 25 June 2011 Full Text: \| Download PDF
	+ -	Show Abstract The LEED (Leadership in Energy and Environmental Design) environmental certification system has developed as a standard for sustainable project planning, though research into its economic impacts have been limited. The main objective of this study is to investigate the economic impacts that two LEED Public Transportation Access (PTA) components, a bus and a light rail system, have on appraised values of land parcels. This study developed a predictive model to quantify the impacts that the two LEED PTA components would have on the appraised unit values of unimproved land parcels. First, a LEED PTA indication map using Geographical Information System (GIS) was created to randomly select unimproved parcels. Second, the PTA‐qualified parcels were selected from the unimproved parcels to use for this study. Lastly, a multiple linear regression method with a One‐way ANOVA analysis was performed to predict the unit value of selected parcels by analyzing how the appraised unit value ($/ft²) of parcels was affected by the PTA credits. The results indicate that the two PTA LEED components have a significant impact on the appraised land values, which suggests an economic benefit for adopting the LEED PTA components.

Select this Article		Continuous Quality Improvement Techniques for Data Collection in Asset Management Systems G.C. Migliaccio, A. M. ASCE, Susan M. Bogus, M. ASCE, and A. A. Cordova‐Alvidrez Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000427 Posted ahead of print 6 June 2011 Full Text: \| Download PDF
	+ -	Show Abstract Transportation infrastructure assets are among the largest investments made by governmental agencies. These agencies use data on asset conditions to make decisions regarding the timing of maintenance activities, the type of treatment, and the resources to employ. To collect and record these data, agencies often utilize trained evaluators who assess the asset either onsite or by analyzing photos and/or videos. These visual assessments are widely used to evaluate conditions of various assets, including pavement surface distresses. This paper describes a Data Quality Assessment & Improvement Framework (DQAIF) to measure and improve the performance of multiple evaluators of pavement distresses by controlling for subjective judgment by the individual evaluators. The DQAIF is based on a Continuous Quality Improvement cyclic process that is based on the following main components: a) assessment of the consistency over time — performed using linear regression analysis, b) assessment of the agreement between evaluators — performed using inter‐rater agreement analysis, and c) implementation of management practices to improve the results shown by the assessments. A large and comprehensive case study was employed to describe, refine and validate the framework. When the DQAIF is applied to pavement distress data collected onsite by different evaluators, the results show that it is an effective method for quickly identifying and solving data collection issues. The benefit of this framework is that the analyses employed produce performance measures during the data collection process, thus minimizing the risk of subjectivity and suggesting timely corrective actions. The DQAIF can be used as part of an asset management program, or in any engineering program where the data collected are subjected to the judgment of the individuals performing the evaluation. The process could also be adapted for assessing performance of automated distress data acquisition systems.

Select this Article		Analysis of Cost Estimating Competencies Using Criticality Matrix and Factor Analysis Anwar Alroomi, “David” Hyung Seok Jeong, and Garold D. Oberlender Journal of Construction Engineering and Management doi:http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000351 Posted ahead of print 12 January 2011 Full Text: \| Download PDF
	+ -	Show Abstract Perhaps the greatest challenge facing the cost estimating community over the next decade is the loss of knowledge and experience of highly experienced estimators as a high percentage of them are retiring and a shortage of qualified cost estimators is evident in the construction industry. This study identified 23 core estimating competencies classified into skills, knowledge, and personal attributes and also quantified the degree by which new estimators lack each competency. In total, 228 completed questionnaires were collected through the CII member companies, through “AACE‐I” and “ASPE” workshops. An estimating core competency criticality matrix was developed to prioritize competencies based on the combined effects of the level of importance of each competency and its associated gap between the ideal and actual level of competency. The factor analysis method was applied to investigate the correlation effects of the 23 estimating competencies and resulted in seven core estimating competency factors representing the core estimating competencies. The findings of this study can help companies in the construction industry assess their estimators’ capabilities and design appropriate training programs for their estimators based on their specific needs.