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Select this Article		Finite Element Analyses of Mechanically Stabilized Earth Walls Subjected to Midlevel Seismic Loads Rebecca M. Walthall, A. M. ASCE, Judith Wang, A. M. ASCE, Panos Kiousis, A. M. ASCE, and Aziz Khan, P.E. Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000361 Posted ahead of print 26 April 2012 Full Text: \| Download PDF
	+ -	Show Abstract The objective of this study is to examine the performance of specific detailing components of Mechanically Stabilized Earth (MSE) walls when subjected to midlevel seismic excitations such as those expected in the state of Colorado. The motivation for this study is the elevated Peak Ground Accelerations (PGAs) mandated by the 2007 4^th Edition of the American Association of State Highway and Transportation Officials (AASHTO) Load and Resistance Factor Design (LRFD) Bridge Design Specifications. According to this revision, highway‐related projects must be designed for an elevated 1,000‐year return period earthquake as opposed to the earlier editions' 500‐year return period earthquake. In this study, finite element analyses are performed using LS‐Dyna to examine the displacement‐based, dynamic behavior of individual MSE wall components, such as the geogrid reinforcement and the wall facings. Walls at two heights, 4.57 m (15.0 feet) and 9.14 m (30.0 ft), with two types of facings (modular block and segmental panel walls) and reinforced using geogrids are modeled based on Colorado Department of Transportation (CDOT) drawings. These walls are subjected to three synthetic earthquake motions generated by the United States Geological Survey's (USGS) 2002 deaggregation tool for three sites spread across the geographical extents of the state of Colorado. The results of this study show that typical MSE walls perform well with respect to connection details when subjected to midlevel seismic loads.

Select this Article		Performance‐Based Design for a Tall‐Pier Bridge Prototype in Massive Earthquakes Ching‐Jong Wang Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000359 Posted ahead of print 27 April 2012 Full Text: \| Download PDF
	+ -	Show Abstract This study aims to determine a cost‐effective design for mitigating the dynamic response of multi‐span tall‐pier bridges subjected to longitudinal seismic excitation. Time history solutions are provided for a dynamic system of discrete and finite elements which models sliding friction, collision contact, and non‐linear behaviors. The approach involves conducting vulnerability tests on parametric models comprising various parameters for piers, bearings, and backfill soils. The bridge prototype as evolved combines the use of adapted rubber bearing and cemented backfill. It satisfied specified performance criteria without structural damage under six strong motions from Kobe and Chi‐Chi earthquakes. The margins of safety and serviceability were ensured by a statistical analysis considering the uncertainty of backfill and bearing properties.

Select this Article		Live Load Test Comparison and Load Ratings of a Post‐Tensioned Box Girder Bridge Dereck J. Hodson, Paul J. Barr, and Leonardo Pockels Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000356 Posted ahead of print 12 April 2012 Full Text: \| Download PDF
	+ -	Show Abstract This paper presents a comparison of two live‐load tests performed on a post‐tensioned, box‐girder bridge. The initial live‐load test was performed more than 20 years before the most recent test. Strain gauges were placed at the same location for both tests. In each case, the bridge was subjected to nearly identical loads so that changes in strain could be correlated as a heavy truck drove across the instrumented bridge. A comparison of the bridge behavior based on the two load tests is presented. The changes in recorded strain were also used to validate a detailed finite‐element model using primarily shell elements. From this calibrated finite‐element model, the live load distribution factors for moment were obtained. These factors were used to calculate both the inventory and operating rating factors of the bridge. These values were compared to those calculated in accordance to the AASHTO LRFD Specifications distribution factors. It was found that the rating factors could be increased by 26% due to the partial fixity caused by the integral abutments.

Select this Article		Imposed Deformations Measured on a Real Integral Structure: The New Airport Terminal Barajas, Madrid ‐ Spain Petschke Tobias, García Eduardo, Pérez Alejandro, and Corres Hugo Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000351 Posted ahead of print 10 April 2012 Full Text: \| Download PDF
	+ -	Show Abstract Experimental research on imposed deformation is generally conducted on small scale laboratory experiments. The attractiveness of field research lies in the possibility to compare results obtained from full scale structures to theoretical prediction. Unfortunately, measurements obtained from real structures are rarely described in literature. The structural response of integral edifices depends significantly on stiffness changes and constraints. The New Airport Terminal Barajas in Madrid, Spain provides with large integral modules, partially post‐tensioned concrete frames, cast monolithically over three floor levels and an overall length of approx. 80 m. The field campaign described in this article explains the instrumentation of one of these frames focusing on the influence of imposed deformations such as creep, shrinkage and temperature. The applied monitoring equipment included embedded strain gages, thermocouples, DEMEC measurements and simple displacement measurements. Data was collected throughout construction and during two years of service. A complete data range of five years is presented and analysed. The results are compared with a simple approach to predict the long‐term shortening of this concrete structure. Both analytical and experimental results are discussed.

Select this Article		Computer‐Aided Assessment of Progressive Collapse of Reinforced Concrete Structures According to GSA Code Huda Helmy, Hamed Salem, and Sherif Mourad Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000350 Posted ahead of print 10 April 2012 Full Text: \| Download PDF
	+ -	Show Abstract A building is subjected to progressive collapse when a primary vertical structural element fails resulting in failure of adjoining structural elements which, in their turn, cause further structural failure leading eventually to partial or total collapse of the structure. The failure of a primary vertical support might occur due to extreme loadings such as a bomb explosion in a terrorist attack, a car colliding with supports in a parking garage, an accidental explosion of explosive materials and severe earthquake. Different design codes address the progressive collapse of structures due to the sudden loss of a main vertical support such as the General Services Administration (GSA) and the Unified Facilities Criteria (UFC). Alternative Path Method (APM) is the main analysis method for evaluating the hazard of progressive collapse in the two codes. The (APM) requires that the structure be capable of bridging over a missing structural element, with the resulting extent of damage being localized. In the current study, a progressive collapse assessment according to the GSA code is carried out for a typical ten‐story reinforced concrete framed structure. The structure is designed according to the building code requirements for structural concrete (ACI 318‐08). Fully nonlinear dynamic analysis for the structure is carried out using the Applied Element Method (AEM). According to the GSA code, a primary vertical structural element is removed and the collapse area is investigated. The investigated cases include the removal of a corner column, an edge column, an edge shear wall, internal columns, internal shear wall and a corner shear wall. The numerical analysis showed that for an economic design, the analysis should consider slabs and can't be simplified into a 2D or 3D frame analysis. Neglecting the slabs in the progressive collapse analysis is a very conservative approach which may lead to uneconomic design. Reinforced concrete structures designed according to the ACI 318‐08 met the GSA limits and were found to have a low potential for progressive collapse.

Select this Article		Decision Tree Based Deterioration Model for Buried Wastewater Pipelines Syadaruddin Syachrani, Ph.D., “David” Hyung Seok Jeong, Ph.D., and Colin S. Chung, Ph.D. Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000349 Posted ahead of print 10 April 2012 Full Text: \| Download PDF
	+ -	Show Abstract Asset management provides a managerial decision making framework for public agencies to monitor, evaluate, and make informed decisions about how to best maintain vital civil infrastructure assets. Among many steps required for implementing asset management, developing an accurate deterioration model is one of the key components since it helps infrastructure agencies predict remaining asset life. The accuracy of deterioration models highly depends on the quality of input data and the computational technique used in data analysis. Among many options of computational techniques, decision tree offers the combination of visual representation and sound statistical background. The visual representation enables the decision‐maker to identify the relationship and inter‐dependencies of each decision and formulate an appropriate prediction. This study developed a decision tree based deterioration model for sewer pipes. The performance of the new model is then compared to conventional regression and neural networks based models that are also developed using the same datasets. The result shows that decision tree outperformed other techniques in terms of accuracy (error rate). The paper also discusses different deterioration patterns of different categories of pipes.

Select this Article		Corrosion Assessment of Reinforced Concrete Deck in a Jetty Structure Damaged by Chloride Attack Ali Dousti, Masoud Moradian, Seyyed Rahman Taheri, Reza Rashetnia, and Mohammad Shekarchi Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000348 Posted ahead of print 10 April 2012 Full Text: \| Download PDF
	+ -	Show Abstract The long‐term behaviour of concrete structures has shown that their main cause of distress is reinforcement corrosion. One of the most aggressive exposure conditions for concrete is the marine environment such as Persian Gulf region. In this condition, reinforcement corrosion due to diffusion of chloride ions is the main deterioration mechanism. In these conditions chloride penetration and chloride induced reinforcement corrosion rates can be very high, often leading to a reduced service life. This paper presents results of a study performed on a 40 year old reinforced concrete jetty structure in Mahshahr Petrochemical Special Zone (MPSZ), in the Persian Gulf region which suffered extensive deterioration due to chloride‐induced corrosion. On the base of visual inspection, in situ and laboratory tests, it was obvious that the structure was not enough qualitative designed and built.

Select this Article		Health Monitoring of Structures Using Statistical Pattern Recognition Techniques Ahmed S. Noman, Farah Deeba, and Ashutosh Bagchi, M. ASCE Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000346 Posted ahead of print 5 March 2012 Full Text: \| Download PDF
	+ -	Show Abstract The primary objective of Structural Health Monitoring (SHM) is to determine whether a structure is performing as expected or there is any anomaly in its behavior as compared to the normal condition. It is also useful in detecting the existence, location and severity of damage. Vibration based damage detection methods are very frequently used in SHM. But due to complicated features of real life structures, there are uncertainties involved in the key input parameters (e.g. measured frequencies and mode shape data) which affect the performance of these methods. If vibration based methods are incorporated with semi‐analytical method such as statistical pattern recognition techniques, better accuracy can result in structural health assessment. This paper explores the statistical pattern recognition techniques for damage detection and/or degradation in structures. A case study, the Portage Creek Bridge in Victoria, British Columbia has been used. The following two approaches of the statistical pattern recognition techniques have been used: statistical pattern comparison, and statistical model development. After filtering and normalizing the data; obtained from the SHM system installed in the bridge damage sensitive features have been extracted by Auto Regressive (AR) modeling of time series data. Both idle and excited states of the bridge are considered in this case. From the statistical analysis of the strain and acceleration data, it has been found that while the bridge is in a good condition, there is a small, but steady deterioration in its performance. The study also demonstrates the feasibility of the statistical pattern recognition techniques in assessing the structural condition of a practical structure.

Select this Article		Failure Analysis of a Highway Dip Slope Slide W. F. Lee, H. J. Liao, M. H. Chang, C. W. Wang, S. Y. Chi, and C. C. Lin Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000345 Posted ahead of print 5 March 2012 Full Text: \| Download PDF
	+ -	Show Abstract This paper presents the numerical modeling work as part of forensic investigation on a catastrophic roadside slope failure in Taiwan. It includes three stages of numerical modeling analysis of the failure slope. The 2D limited equilibrium analysis numerical modeling is first carried out to check the original design. A series of parametric studies are then introduced to investigate the influences of controlling design factors on slope stability. Finally, 3D finite difference element analysis is conducted to further examine possible failure scenarios and the failure states. As a result of this study, failure mechanism and triggering factors were possibly verified via the numerical analyses. Purpose of the presented study is hoped to introduce the applications of numerical modeling in similar forensic investigations, as well as appropriate means of adapting numerical modeling in a forensic investigation.

Select this Article		Forensic Studies of Geosynthetic Reinforced Structure Failures Jason Y. Wu, P.E., M. ASCE and Nelson N. Chou, P.E., F. ASCE Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000344 Posted ahead of print 5 March 2012 Full Text: \| Download PDF
	+ -	Show Abstract Failure studies are important for engineering practices. Lessons learned from failures provide valuable information to help ensure future success. This paper explores the causes of failure in mechanically stabilized earth (MSE) structures reinforced with geosynthetics. Nineteen cases of MSE failure are carefully examined and quantitatively studied. The results of the forensic study indicate that intense rainfall is the primary natural cause for the observed MSE failures. Incorrect engineering practices are also implicated in the MSE malfunctions, while the study determines that inadequate project planning and site exploration, and poor construction quality are the most important reasons for human‐caused failures. In addition, the study also shows that MSE failures occur due to a lack of essential training in traditional slope stability analysis rather than from any deficiency in MSE expertise. The results of this study offer useful lessons to MSE professionals for not only improving their engineering practices, but also ensuring more reliable MSE in the future.

Select this Article		Inspection and Diagnosis System for Wood Flooring A. Delgado, J. de Brito, and J. D. Silvestre Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000342 Posted ahead of print 5 March 2012 Full Text: \| Download PDF
	+ -	Show Abstract This paper presents an expert system to support the inspection and diagnosis of wood applied as a floor covering (Wood Flooring ‐ WF). The defects that may affect WF along with their probable causes are classified in this system. The inspection system also embraces the correlation matrices between defects and between defects and probable causes, the classification of the diagnosis methods and the repair techniques suitable for each WF defect. This paper also includes an example of an individual defect file containing a complete characterization and the most suitable diagnosis methods and repair techniques. This inspection system was validated through standard inspections of 90 WFs applied on floors indoors and 8 applied in exterior areas, in a total of 35 buildings.

Select this Article		Comparative Performance of Stiffened Sandwich Foam Panels under Impulsive Loading Manmohan Dass Goel, Vasant A. Matsagar, Steffen Marburg, and Anil K. Gupta Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000340 Posted ahead of print 10 February 2012 Full Text: \| Download PDF
	+ -	Show Abstract Modeling and numerical simulation of foam sandwich panels subjected to impulsive loading are presented. The sandwich panels consist of steel sheets at front and back with two varieties of foam cores in between. Stiffeners are provided at back‐sheet for improved response. The dynamic response of stiffened steel plate (SSP), sandwich foam panel (SFP), and stiffened sandwich foam panel (SSFP) are compared. The foam material modeling accounts for elastic‐plastic behavior with volumetric hardening. The finite element based numerical simulation for dynamic analysis is performed employing a combination of shell and solid elements for sheets and foam, respectively. Central point displacements caused due to the impulsive load of peak pressure of 0.7 MPa and lasting for 15 millisecond applied uniformly to the sandwich panels are studied. The analysis is carried out with an objective of understanding the effects of foam thickness, type of foam, and the stiffener configurations. The results obtained indicate that the SSFP considerably increase the resistance to impulsive loading as compared to the SSP and SFP.

Select this Article		Fuel Storage Container Performance during the 2011 Tohoku Japan Tsunami Clay Naito, Daniel Cox, Qi‐Song “Kent” Yu, and Hillary Brooker Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000339 Posted ahead of print 10 February 2012 Full Text: \| Download PDF
	+ -	Show Abstract Field investigation of infrastructure damage following the March 2011 Tohoku Japan Tsunami uncovered failure of numerous fuel storage containers as a result of the high inundation depths and velocities associated with the event. Observations focused on two areas, Ishinomaki and Onagawa, Japan, where the inundation depths of up to 6 m and 17 m, respectively, were measured. The failure modes observed include: crushing of containers as a result of inward hydrostatic forces or debris impact; tie down failures as a result of elevated buoyancy forces, and sliding failures as a result of the hydrodynamic forces imparted during the event. The loss of restraint resulted in movement of the containers outside of their containment walls, fuel spillage, and ground contamination. Sample calculations based on observed container failure, water levels, and estimated flow velocities illustrate the demands and failure patterns observed. A retrofitting mechanism is proposed to minimize loss of fuel storage containers during tsunami events.

Select this Article		Backcalculation of Ultra‐Thin Whitetopping Pavement Based on Saint‐Venant's Principle Haifang Wen, Ph.D., P.E., M. ASCE and Xiaojun Li Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000338 Posted ahead of print 10 February 2012 Full Text: \| Download PDF
	+ -	Show Abstract Whitetopping (WT) or ultra‐thin whitetopping (UTW) overlay is defined as a Portland Cement Concrete (PCC) overlay on an existing deteriorated hot mix asphalt (HMA) pavement to improve both the structural and functional capability of HMA. In the past two decades, UTW overlays have gained great acceptance as an alternative to HMA overlay. However, there is a lack of a reliable method to evaluate the performance of in‐service UTW pavements. Due to the small slab sizes of UTW pavements, backcalculation of pavement layer properties, based on the Falling Weight Deflectometer (FWD), is challenging. This study developed a new approach, Critical Distance Method, based on Saint‐Venant's principle, to backcalculate the PCC and equivalent substructure moduli of UTW pavement. It was proven to be an effective approach to determine the layer properties of UTW pavement, based on the finite element simulations. Traditional backcalculation methods, such as AREA theory and Modcomp6 program, were used as comparison in the simulation and a case study. It was found that the Critical Distance Method is more accurate for evaluating UTW pavement. Further field verification of the Critical Distance Method is needed.

Select this Article		Sudden Complete Collapse of Zumrut Apartment Building and It's Causes M. Yasar Kaltakci, Mehmet Kamanli, Murat Ozturk, M. Hakan Arslan, and H. Husnu Korkmaz Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000337 Posted ahead of print 2 February 2012 Full Text: \| Download PDF
	+ -	Show Abstract In recent years, buildings and structures in Turkey have frequently failed or suddenly sustained damage due to their own weight or other loads. The most dramatic failure was the Zumrut Apartment Building disaster: a 9‐story reinforced concrete building in Konya that collapsed on February 2^nd, 2004, leaving 92 people dead. This study will investigate the cause of the building damage and failure. The significant mistakes made during the design and construction of the building will also be considered. This study was divided into three sections: site investigation, analytical study and experimental study. The evaluation of the building failure relating to the vertical load‐bearing members will be presented using observations from the site investigations, the test results obtained from specimens taken from the failed building and the findings of an analytical study involving modeling the building using the finite element method.

Select this Article		Performance of a Prestressed Concrete Pedestrian Bridge System under Equivalent Static Lateral Impact Loads Eray Baran, Arturo E. Schultz, and Catherine E. French Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000336 Posted ahead of print 2 February 2012 Full Text: \| Download PDF
	+ -	Show Abstract The resistance of Prestressed Concrete Through‐Girder (PCTG) pedestrian bridges to lateral loads was studied in response to the increasing number of vehicular impacts in the United States. This research was motivated by the lack of reported studies analyzing the behavior of such bridges to lateral impact loads, as well as their potential vulnerability in comparison with bridges that are better able to redistribute and transfer locally‐applied impact loads through alternate load paths. Pedestrian bridges are of lighter construction than highway bridges and they do not have the high degree of redundancy, making them more vulnerable to collapse in the event of vehicular impact. Results from static lateral load analyses using three‐dimensional, geometrically nonlinear, full‐scale finite element (FE) models of a typical bridge system and bridge subassemblages were used to evaluate the characteristics of the system. The FE models were calibrated with experimental test data on typical subassemblages and connection details for PCTG bridges. Results of the experimental part of the program have already been published elsewhere. This paper summarizes the observations obtained from nonlinear static FE analyses of a PCTG pedestrian bridge system subjected to lateral impact loads. The analyses indicated that the location of impact, the type of connector and the flexibility of the end support details affected bridge performance. Improved connection details are suggested for enhanced PCTG pedestrian bridge performance.

Select this Article		A Case Study of the Rehabilitation of the Core Zone of an Earth‐Fill Dam Geu‐Guwen Yea, Tae‐Hyung Kim, Jae‐Hong Kim, and Hong‐Yeon Kim Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000335 Posted ahead of print 2 February 2012 Full Text: \| Download PDF
	+ -	Show Abstract This paper provides a detailed study of remediation work on the core zone of a damaged earth‐fill dam. The relevant material includes a review of the dam surface survey data, leakage monitoring data, drilling method, grouting material and drilling and grouting procedure. A compaction grouting method was selected as the remediation technique. In addition, the reduction and prevention of leakage and settlement were assessed. Compaction grouting was successful for filling voids, closing channels, and compacting the disturbed core soils. The loose or voided zones were properly filled, and the leakage was reduced after compaction grouting. Verification of the compaction grouting work was performed by evaluating the grouting pressures and volumes injected internally as well as by monitoring the dam leakage rate and tracer externally. All of these factors provide a good indication of changes inside the core of the dam, including reduction or closure of the leakage channels in the dam core.

Select this Article		Performance of Screen Enclosures under Repeated Loading Cycles Jeyre Lewis, Sungmoon Jung, Ph.D., M. ASCE, and Primus Mtenga, P.E., Ph.D., M. ASCE Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000334 Posted ahead of print 19 January 2012 Full Text: \| Download PDF
	+ -	Show Abstract Aluminum screen enclosures suffer from significant damage in hurricanes. As an attempt to minimize the damage on screen enclosures, experimental investigations were conducted to study how the screen enclosures perform when they are subjected to repeated loading cycles. The loading cycles mimic gradually increasing hurricane winds, while considering the fluctuating nature of the wind. Three types of specimens were constructed and tested. Their overall geometry was the same but their bracing strategies were different. Three damage indices were employed to analyze the data. Qualitative assessment and comparison of damage was also conducted. Overall, K‐type bracing was most effective followed by the cable bracing. Lack of bracing resulted in sudden failure. Beam‐to‐host connections were very critical in preventing catastrophic failure. Suggestions for improving the beam‐to‐host connections were provided along with other measures to mitigate the damage on screen enclosures. Where feasible, the most important measure to reduce damage would be the installation of a proper bracing system, but other proposed measures would also strengthen the structure against hurricane winds.

Select this Article		Another Look at the Collapse of Skyline Plaza at Bailey's Crossroads, Virginia Jeffrey Schellhammer, Norbert J. Delatte, and Paul A. Bosela Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000333 Posted ahead of print 19 January 2012 Full Text: \| Download PDF
	+ -	Show Abstract On March 2, 1973, the Skyline Plaza apartment building in Bailey's Crossroads, Virginia collapsed while under construction. The Occupational Health and Safety Administration (OSHA) requested an investigation from the National Bureau of Standards (NBS, now the National Institute of Standards and Technology, or NIST). The NBS team concluded that the most likely cause of the collapse was a punching shear failure of the 23^rd floor slab. The two factors that contributed to this were premature removal of shores below the 23^rd floor slab, and the low strength of the 23^rd floor concrete in the area supporting the weight of the 24^th floor slab. The engineer's structural drawings required two full stories of shoring and one story of reshoring while a concrete slab was cast. The project architect and structural engineer were sued and held responsible, even though their specific shoring instructions had been ignored. This case study reviews the available published information on the case in order to determine what lessons can be learned. The case is suitable for inclusion in variety of courses in the civil engineering and construction curriculum.

Select this Article		The 1976 Montreal Olympics: A Case Study of a Project Management Failure Ashish Patel, Paul A. Bosela, and Norbert J. Delatte Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000332 Posted ahead of print 19 January 2012 Full Text: \| Download PDF
	+ -	Show Abstract A successful engineering project must include its timely and economic completion. A project management failure can lead to delays and cost overruns. One example of a project that greatly exceeded its projected budget is the construction of the multiple facilities for the 1976 Olympic Games in Montreal, Canada. These included the Olympic Stadium, a Velodrome for bicycle events, and the Olympic Village to house the athletes. This case study reviews the circumstances of the cost increases and the design decisions and other circumstances that led to them. The difficulties were brought on by an unrealistic schedule to complete the facilities before the fixed start date of the Games, combined with an unusually cavalier attitude toward project costs, exacerbated by political tensions. Although the original cost estimate for the facilities was $ 120 million, the final cost was $ 1.5 billion with $ 830 million for the main stadium alone. Part of the justification for the expense of the facilities was the hope that the facilities would be useful for future athletic events — the record on this is mixed at best. The lessons learned can be applied to other projects in order to better control costs.

Select this Article		Long Term Structural Deficiencies in a Mat Foundation on Clay Soil Gaetano Russo, M. ASCE, Margherita Pauletta, and Nunzio Scibilia Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000331 Posted ahead of print 19 January 2012 Full Text: \| Download PDF
	+ -	Show Abstract A three storey building with a mat foundation consisting of a slab on a grid of grade beams performed poorly on clay soil. Cracking of the slab became progressively worse due to incorrect design and to fluctuations in groundwater pressure under the foundation. The cyclic presence and absence of water rusted steel reinforcement, and the sulfates in the clay soil caused formation of ettringite in the concrete. Plastic hinges formed in the slab, and settlements occurred, causing damage to the beams. The situation is still in progress and may lead the structure to collapse under normal service conditions. The geotechnical and structural investigations performed to survey and assess the aforementioned problems are described in this paper. The causes and the consequences of the detected anomalies are analyzed, and a prediction of potential future structural problems is provided. A strengthening procedure is proposed, and an estimate of the cost to realize it is provided. Recommendations are offered to help avoid the problem in new constructions.

Select this Article		Forensic Investigation of Deteriorated Concrete in Plantation East Culverts, City of Benbrook, Texas N. Yazdani, F. ASCE, S. Hossain, M. ASCE, J. Hossain, and W. Shumac, III Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000330 Posted ahead of print 19 January 2012 Full Text: \| Download PDF
	+ -	Show Abstract Two underground concrete box culverts were installed below ground on Plantation Drive in the City of Benbrook, Texas, in 1991. The culverts consisted of precast segments with case‐in‐place (CIP) collars/bends. Concrete started deteriorating and spalling at several CIP bend locations as early as 1993. The concrete continued to deteriorate over the subsequent years. An investigation was launched herein to determine the cause and extent of the concrete degradation. The geotechnical investigation involved Resistivity Imaging, soil boring and Photo‐Ionic Detection for exploring any soil contamination around the culverts that may enhance the concrete deterioration. Visual inspection of the deteriorated concrete helped to examine the clear concrete cover. Concrete cores were taken and tested for strength and deterioration. No soil contamination was observed at the site. The culvert water acidity was neutral. Therefore, the contamination in the underground tunnel/box‐culvert may not be related to the soil contamination or leakage from sewerage pipes around the culvert areas. The collected concrete core inspection and testing showed that most of the bend concrete is badly deteriorated. Although the strength of some of the more intact bends is acceptable, most of the bend concrete simply does not have sufficient strength, integrity, and ductility to effectively carry the service loads imparted on them. The rebars inside the cores were extensively deteriorated and lost much of their strengths and ductility. The visual inspection showed that the insufficient clear covers were utilized in the culvert wall and the slab; this was the likely cause of the premature concrete deterioration. Based on the investigation performed herein, immediate rehabilitation steps were recommended.

Select this Article		Progressive‐Collapse Simulation and Critical Region Identification of a Stone Arch Bridge Zhen Xu, Xinzheng Lu, Hong Guan, Xiao Lu, and Aizhu Ren Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000329 Posted ahead of print 19 January 2012 Full Text: \| Download PDF
	+ -	Show Abstract Progressive collapses of arch bridges have repeatedly occurred in recent years, resulting in many casualties and significant property losses. Based on an actual recent and serious progressive collapse of a stone arch bridge, this paper simulated the complete progressive‐collapse process using the general purpose finite element (FE) program, MSC.Marc. The simulation adopted a 3D FE model and performed a nonlinear analysis using the contact algorithm in conjunction with the element deactivation technique. The potential causes of the progressive‐collapse of the stone arch bridge were also evaluated. Furthermore, the importance of different components of the stone arch bridge was determined with the conception of generalized structural stiffness; thus, the most critical and vulnerable regions of the bridge were identified. The results of the simulated progressive‐collapse process agreed well with the actual process, and the predicted critical regions were both correct and realistic. This study also provides important references for the analysis and prevention of progressive collapses of stone arch bridges.

Select this Article		Dynamic Modulus of HMA and Its Relationship to Actual and Predicted Field Performance Using MEPDG Laith Tashman and Muthukumaran Elangovan Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000328 Posted ahead of print 16 January 2012 Full Text: \| Download PDF
	+ -	Show Abstract A database of dynamic modulus values for typical Superpave mixes widely used in the state of Washington was developed and used to investigate the sensitivity of the dynamic modulus to aggregate gradation. Seven Job Mix Formulas (JMF) were selected for the study. Percent passing sieve #200 of these mixes were changed by ± 2% to prepare additional mixes referred to as ‘modified mixes’. Statistical analysis showed that using different JMF mixes significantly affected the dynamic modulus. This was not the case when modifying the JMF by changing the percent passing #200. A simple evaluation of the prediction accuracy of the new Mechanistic‐Empirical Pavement Design Guide (MEPDG) was conducted in which the measured dynamic modulus was used as a key input parameter to predict pavement distresses. Level 1 and Level 3 predictions of rutting, longitudinal cracking, alligator cracking, and IRI were compared with field performance data. The Design Guide predicted IRI and alligator cracking reasonably well. The predicted rutting of the JMF mixes agreed well with the dynamic modulus trend. It was found that the ±2% change in the passing #200 aggregate gradation did not affect the predicted distress significantly.

Select this Article		An Ordinal Logistic Regression Model for Predicting AC Overlay Cracking Yuhong Wang, P.E., M. ASCE Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000327 Posted ahead of print 16 January 2012 Full Text: \| Download PDF
	+ -	Show Abstract Predicting performance of asphalt concrete (AC) overlay is important for both pavement design and management. Based on 328 AC overlay sections from the Long‐Term Pavement Performance (LTPP) program, ordinal logistic regression models were developed in this study to predict the probability of severity levels for alligator cracking. It was found that the alligator cracking is significantly affected by: alligator cracking of the existing pavement, thickness of overlay, thickness of the existing AC, age of pavements after resurfacing, truck volume, freeze‐thaw cycles, and the amount of precipitation per wet day. In addition, it was found that the use of recycled asphalt pavement (RAP) in the amount specified in the SPS 3 experiment and pre‐overlay treatment significantly affect overlay cracking. Both statistical conformance tests and empirical verification using independent data indicate that the developed models are reasonably accurate. The model can generate the probability of a pavement staying at a certain distress level as well as the odds ratio, which enables highway agencies not only predict probability of cracking, but also assess the confidence of making such predictions.

Select this Article		Experimental Study on Two Simple Mechanical Precast Beam‐Column Connections under Reverse Cyclic Loading R. Vidjeapriya and K. P. Jaya Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000324 Posted ahead of print 5 January 2012 Full Text: \| Download PDF
	+ -	Show Abstract This paper presents the experimental investigation of one third‐scale precast concrete beam‐column connections subjected to reverse cyclic loading. The precast specimen and monolithic specimen were designed for the same strength. For the first precast connection, the beam is connected to the column with corbel using a cleat angle with a single stiffener and for the second precast connection, cleat angle with two stiffeners were used. The sub‐assemblage specimens have been subjected to cyclic displacement controlled lateral loading, applied at the end of the beam. The ultimate load carrying capacity, load ratio, hysteretic behaviour, energy dissipation, equivalent viscous damping ratio, ductility factor and strength degradation of both the precast and monolithic specimen were measured and their performance was compared. The results showed that ultimate load carrying capacity of the monolithic specimen was superior to that of both the precast specimens. The precast specimens were found to exhibit satisfactory behaviour when compared to the monolithic specimen in terms of energy dissipation and ductility.

Select this Article		Sensitivity of Load Distribution in Light‐Framed Wood Roof Systems Due to Typical Modeling Parameters Ranjith Shivarudrappa and Bryant G. Nielson Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000323 Posted ahead of print 2 January 2012 Full Text: \| Download PDF
	+ -	Show Abstract Since failure of roof systems in past high wind events have demonstrated the consequences of not maintaining a continuous load path from the roof to the foundation, many studies have been conducted to better understand this load path, including how loads are distributed in the system. The present study looks to add to the current knowledge of the vertical load path by focusing on uplift loads and by considering the sensitivity of different modeling parameters. This is done by developing and assessing load influence coefficient contours for various roof‐to‐wall (RTW) connections. An analytical model of a light‐framed wood structure using finite element software is developed. The model has a gable roof system comprised of fink trusses and is modeled in a highly detailed fashion including the explicit modeling of each connector/nail in the system. The influence coefficient plots indicate that the distribution of loads is indeed sensitive to the overall stiffness of RTW connections but is not overly sensitive to their relative stiffnesses. This was investigated by looking at cases where all connections have the same stiffness and cases where they can have different stiffnesses. However, the relative stiffness begins to have a larger impact as they begin to soften due to yielding. Furthermore, the stiffness of the sheathing connectors did not appear to have much of an impact on the distribution of load but the sheathing stiffness itself did have a notable impact.

Select this Article		Safety Assessment of Four Masonry Churches by a Plate and Shell FE Non‐Linear Approach Gabriele Milani and Gennj Venturini Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000321 Posted ahead of print 20 December 2011 Full Text: \| Download PDF
	+ -	Show Abstract A full 3D finite element (FE) homogenized modeling computer program for the evaluation of the non‐linear static behavior of entire masonry structures subjected to horizontal actions is presented and tested on four large scale masonry churches located in the central region of Italy. At the structural level, masonry is modeled as a homogeneous, orthotropic material featuring softening in tension, shear and compression. Rigid‐infinitely resistant triangular elements connected by elastoplastic interfaces are used to perform full‐scale non‐linear analyses. To reduce further processing time needed for the simulations, preliminary FE limit analyses were conducted in order to identify the failure mechanisms, and hence the interfaces which undergo plasticization during the deformation process. In this way, it is possible to concentrate non linearity exclusively on those interfaces which prove active in the limit analysis problem. Finally, full non‐linear pushover curves are compared to collapse loads, the latter provided by a limit analysis which assumes a limited number of possible pre‐assigned failure mechanisms, as required by the recent Italian guidelines on monumental buildings.

Select this Article		Horizontal Translocation of a High Rise Building: Case Study Tong Guo, Aiqun Li, Longwu Wei, and Yu Gu Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000320 Posted ahead of print 20 December 2011 Full Text: \| Download PDF
	+ -	Show Abstract This case study presents the horizontal translocation of the Hongxing Mansion, a high rise building in China, which was moved transversally for 26m due to the modification of urban planning. The 13‐storeyed reinforced concrete (RC) frame‐wall structure was built in 2002 with a total height of 63.2m and a total weight of 109,881kN, making the project unique as compared to other similar cases. The executive process of this project is introduced, including the initial planning, design and construction procedures. A load underpinning system was proposed that can transfer the vertical loads uniformly to the rails and distribute the propelling loads from the loaded end to the other end of the building. Anchor jacked piles were used at the original foundation due to the limited indoor clear height so that rails in the original basement can be well supported without the need of large piling machines. A special moving system was proposed and successfully applied, which combined the advantages of pull and push, so that the efficiency and stability of moving were guaranteed. The removable reaction frames were used to alleviate the energy accumulation in tendons and the sudden energy release when the building started to move. Finally, the columns and walls were connected with the new foundation without diminishing their seismic capacities. The design and construction methods in this project provide references to buildings in need of translocation.

Select this Article		Effect Of Slab Shear reinforcement on the Performance of Shear Wall‐Floor Slab Connection S. Greeshma and K.P. Jaya Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000319 Posted ahead of print 20 December 2011 Full Text: \| Download PDF
	+ -	Show Abstract The floor slabs and shear walls together act as a rigid jointed frame in resisting gravity loads and lateral forces due to wind and earthquake. The junction between the wall and slab is a key force resisting element which is subjected to severe stress concentration. The performance of the connection can influence the pattern and distribution of lateral forces among the vertical elements of the structure. In the present study, two different reinforcement detailing adopted, such as (i) Conventional joint with the provision of U hooks connecting shear wall and slab (ii) Extending the slab reinforcement into the shear wall as 90° bent at the core region with the provision of shear reinforcement in the slab. Analytical investigations were carried out using ANSYS to study the performance of the shear wall ‐ slab connection with these detailings. The reinforced concrete model consists of a material model to predict the failure of brittle materials, applied to a three dimensional solid element in which reinforcing bars may be included. Good energy dissipation capacities were observed with the provision of shear reinforcement for an effective width of the slab when compared with conventional joint. The experimental results were compared with analytical results carried out using the Finite Element software ANSYS and it was found that the experimental results are in good agreement with the analytical result.

Select this Article		LiDAR Scan for Blasting Impact Evaluation on a Culvert Structure Christopher Watson, Shen‐En Chen, Haitao Bian, and Edd Hauser Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000318 Posted ahead of print 10 December 2011 Full Text: \| Download PDF
	+ -	Show Abstract This paper summarizes a case study of using 3D LiDAR scanner technology in bridge post‐blast geometric assessments. Terrestrial 3D LiDAR scanners can generate dense point clouds of position information that can be used to establish baseline geometric information for structures and to establish critical dimensional footprints for before and after‐event comparisons. For close range blast effects, the pre‐blast and post‐blast scans of a bridge are proposed to establish blasting induced effects and damage information. The Colony Road culvert bridge was monitored for a nearby construction blasting, where full‐scale three dimensional scans of the bridge have been conducted before and after blasting. The critical sections and geometries are then compared to ensure the safety of the bridge.

Select this Article		Serviceability and Damage Scenario in Irregular RC Structures: Post‐Earthquake Observations and Modelling Predictions Alfredo Maria Ceci, Vincenzo Gattulli, and Francesco Potenza Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000317 Posted ahead of print 24 November 2011 Full Text: \| Download PDF
	+ -	Show Abstract The catastrophic earthquake that struck the city of L'Aquila in early April of 2009 caused extensive damages to University of L'Aquila buildings. Among these edifices those of the Engineering Faculty, in particular, suffered large structural displacements and accelerations that resulted in failures of non‐structural elements (infills, false ceilings, door and window frames), the breakage of wiring and piping systems, and the destruction of furniture and machineries. Of these buildings, so‐called “Edifice A” presents the most critical damage scenario, requiring a significant rehabilitating intervention. The structural behavior of this building, composed of seven independent RC substructures, is the object of intensive investigation, in part because irregularities among these substructures, in terms of geometry, stiffness and weight distribution, provide a rich case study for interpreting different structural and non‐structural damage scenarios. The paper tends to interpret the observed damage through the use of incremental analyses for the evaluation of the threshold between linear and nonlinear structural behavior. For this purpose, several FE models are developed with increasing complexity in the geometry and in the shear wall modeling. The capacity curves obtained by the nonlinear pushover analyses are afterwards compared with the seismic demands perceived by the structures including site effects. Moreover, numerical evaluations of the acceleration producing failures in the infill walls and the split‐face brick walls are made, based on simplified analyses, to achieve an overall description of the structural and non structural damage that occurred.

Select this Article		Structural Aspects and Seismic Performance of One Story Precast Buildings in Turkey Sevket Murat Senel and Mehmet Palanci Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000316 Posted ahead of print 24 November 2011 Full Text: \| Download PDF
	+ -	Show Abstract Large scale seismic performance assessment study based on 98 precast buildings, constructed in high seismicity region of western Turkey, was performed. Structural properties of buildings were obtained from the design projects and then verified by site investigations. Statistical evaluations of inventory buildings have shown that stiffness and ductility capacity of existing buildings are insufficient. This situation indicates that structural deficiencies emphasized in recent earthquakes are not site specific, but wider and common. Seismic performance of precast buildings was estimated by using two different demand spectrums and two different calculation methods. Demand spectrums were constructed by considering site‐specific properties of target region and properties of weak soil sites. Seismic performance of buildings was estimated by using “Capacity Spectrum Method” and “Equal Displacement Approach”. Results of these methods indicated that damage distributions were significantly amplified by the weak soil properties. Distribution of building damages showed that the ratio of extensively damaged and collapsed buildings range from 20% to 80% depending on the site amplification. Considerable amount of moderately damaged buildings imply that monetary losses may also be critical.

Select this Article		The Cappella dei Principi in Firenze (Italy): Experimental Analyses and Numerical Modelling for the Investigation of a Local Failure Gianni Bartoli and Michele Betti Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000315 Posted ahead of print 19 November 2011 Full Text: \| Download PDF
	+ -	Show Abstract The paper reports the results of a research aimed at analysing and interpreting the cracking pattern on the Cappella dei Principi (Prince's Chapel, the Medici's mausoleum) in the Basilica of San Lorenzo (Firenze, Italy). The research was motivated by the sudden collapse of a keystone of an internal barrel vault sustaining one of the lateral apses. After a brief description of the geometry of the structure, the principal results obtained from in‐situ surveys (flat‐jack tests and cored samples) will be described; then the numerical analyses developed both to obtain the static identification of the monument and to assess the possible causes leading to the observed failure will be illustrated. The numerical modelling operation has been performed step by step, from linear and quite simple models built with plane elements up to a non linear model with three‐dimensional elements. The non‐linear FEM, which has been tuned by utilizing the results of the in‐situ measures, allowed to reproduce both qualitatively and quantitatively the behaviour of the structure and its static problems in the area of the barrel vault over the side apses allowing for a justification of the manifested damage. The comprehension of the structural behaviour allows to identify a proper retrofitting strategy.

Select this Article		Mechanical Performance of Liquid‐Applied Roof Waterproofing Systems João Feiteira, J. Grandão Lopes, and J. de Brito Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000314 Posted ahead of print 19 November 2011 Full Text: \| Download PDF
	+ -	Show Abstract This study characterizes the mechanical performance of unreinforced and reinforced liquid applied roof waterproofing systems (LARWS) based on several polymer types and links it to the pedestrian accessibility of roofs. The influence of the thickness and of the reinforcement on the system's performance was assessed on free film samples of cementitious, acrylic, liquid silicone, liquid rubber and polyurethane‐based systems. Tensile properties and resistance to dynamic and static indentation were determined. Further verification of fitness for intended use was assessed with watertightness and flexibility at low temperature tests. The type of product was the most influential parameter on the mechanical performance of LARWS. The cementitious and the polyurethane based systems had a much higher resistance to indentation than all the others, which were, at best, only fit for non‐accessible roofs. The use of internal reinforcement can improve the resistance to dynamic or static indentation. Using an extra coat of the product yields a higher resistance only to dynamic indentation. Deformability or stiffness could not be directly linked to a system's resistance to indentation. A flexibility test at low temperature (−5 °C) found that the mechanical performance of LARWS was not severely affected by those conditions.

Select this Article		Learning from Failure of a Long Curved Veneer Wall: Structural Analysis and Repair Paulo B. Lourenço and Pedro Medeiros Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000313 Posted ahead of print 4 November 2011 Full Text: \| Download PDF
	+ -	Show Abstract Masonry remains the most used material for enclosure and partition walls. Still, cracking often occurs in unreinforced masonry walls under service conditions and scarce information can be found about systemic approaches in real case studies. Here, attention is given to a large building faced with fired clay brick masonry veneer that exhibited significant out‐of‐plane movements only 1.5 years after construction. During the operation of dismounting part of the veneer, partial collapse occurred. The veneer wall, with an elliptical shape, 240 m length and 15 m height, presented no movement joints and insufficient tying. Irreversible expansion of the fired clay brick masonry was expected to be the main reason for damage. The combination of inspection works (visual inspection, pull‐out tests and topographic survey) and advanced structural analysis with finite elements, allowed to understand the damage and propose a repair solution at a fraction of the cost of demolishing and rebuilding a new veneer wall.

Select this Article		Deterioration Prediction of Timber Bridge Elements Using the Markov Chain Shrigandhi Ranjith, Sujeeva Setunge, Rebecca Gravina, and Srikanth Venkatesan Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000311 Posted ahead of print 3 November 2011 Full Text: \| Download PDF
	+ -	Show Abstract Timber bridges require high accumulated maintenance costs which can be many times greater than their initial cost. Infrastructure managers need deterioration models to assist with appropriate decisions on repair strategies and program maintenance schedules by accurately predicting the future condition of timber bridge elements. Markov chain based models have been used extensively in modelling the deterioration of infrastructure facilities. These models can predict the condition of bridge elements as a probabilistic estimate. This paper presents the prediction of future condition of timber bridge elements using a stochastic Markov chain model. Condition data obtained from VicRoads (Roads Corporation of Victoria, Australia) was used to develop transition probabilities. The percentage prediction method, regression‐based optimisation method and non‐linear optimisation technique were applied to predict transition matrices and transient probabilities from condition data. The most suitable deterioration model for timber bridge elements was selected by evaluating the model performances using the Goodness‐of‐fit and reliability tests. It was concluded that the Markov chain developed for deterioration prediction of timber bridges using the non‐linear optimisation technique was mathematically acceptable and predicts the deterioration progression with a reasonable accuracy.

Select this Article		Collapse of a Masonry Wall in an Industrial Building: Diagnosis by Numerical Modelling Juan José del Coz Diaz, José M. Adam, Alfonso Lozano Martínez‐Luengas, and Felipe Pedro Alvarez Rabanal Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000310 Posted ahead of print 3 November 2011 Full Text: \| Download PDF
	+ -	Show Abstract This paper presents the analysis of a failure involving the partial collapse of a masonry wall made of precast concrete blocks in an industrial building due to the action of the wind. A field survey was carried out to investigate the origin of the failure, which pointed to defective building practice as the possible cause. At the same time complementary numerical modeling was performed to simulate the coupled fluid‐structure behaviour, as well as a parametric study and optimization based on Design of Experiments to determine the influence of the principal variables in the wall behaviour in the presence of wind loads. The lessons learned in the course of the study are explained in the final section.

Select this Article		Thermal Buckling Behavior of Open Cylindrical Oil Storage Tanks under Fire Jean C. Batista‐Abreu and Luis A. Godoy, M. ASCE Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000309 Posted ahead of print 3 November 2011 Full Text: \| Download PDF
	+ -	Show Abstract This paper reports computational results of an investigation of oil storage tanks with the shape of open cylindrical shell under thermal loads induced by fire. Interest in this problem arises as a consequence of a catastrophic fire that affected an oil storage facility in Puerto Rico in 2009, which produced failure of 21 large tanks. To identify patterns of deformations that could be expected under various fire conditions, computer modeling has been carried out for one tank geometry. It is assumed that fire occurs outside the tank and induces an increasing temperature field affecting part of the external surface in the circumferential direction. The nonlinear shell response is modeled using finite elements under thermal loads and self‐weight. The nonlinear behavior is computed to identify thermal buckling of the shell as a limit point. The response is initially computed for empty tanks and the influence of various factors is investigated, including the liquid stored, a temperature gradient across the thickness, the circumferential zone affected by fire, and the shell thickness. The results for open tanks show that the location of large out‐of‐plane displacements due to thermal buckling coincides with the heated zone. The importance of thermal gradients in the thickness on the buckling load and mode are shown.

Select this Article		Service Life Predicting of Dam Systems with Correlated Failure Modes Huaizhi Su, Jiang Hu, and Zhiping Wen Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000308 Posted ahead of print 3 November 2011 Full Text: \| Download PDF
	+ -	Show Abstract For many dam projects in China, the 50‐year design reference period is coming to an end. In the last decade, it became clear that remaining service life analysis of existing dams must be used to optimally manage the growing number of aging and deteriorating structures. The uncertainties associated with deteriorating dams require the use of probabilistic methods to properly assess their lifetime performance. Dam system is involved by multiple failure modes, however, conventional assessment and prediction models often neglect the correlations among failure modes, as a result, the remaining service life predicted by these methods is relatively roughly. In this paper, firstly, conventional lifetime distribution functions are introduced. The influences of the correlations among failure modes on series, parallel, or series—parallel structure are discussed respectively, the approach for calculating correlation coefficients is proposed. Secondly, on the basis of the analysis of dam failure causes, failure modes of concrete gravity dams are defined, and the concrete gravity dam is reviewed as a series system with parallel subsystems. Thirdly, the limit state functions for failure modes are given, and quantified progressive deterioration functions for various random variables to describe the aging process of gravity dams are obtained. Based on the correlation analysis and time‐varying theory, prediction model of remaining service life for gravity dam systems is finally proposed. An existing concrete gravity dam is investigated. Failure modes and deterioration mechanisms are studied. The results can be used to better predict the remaining service life of deteriorating dams.

Select this Article		Field Service Conditions of the Oldest Corrugated HDPE Pipe Culvert under Ohio's Roadway Teruhisa Masada, Shad M. Sargand, and James B. Goddard Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000307 Posted ahead of print 24 October 2011 Full Text: \| Download PDF
	+ -	Show Abstract A research institute at Ohio University recently conducted a comprehensive study on highway culvert structures for the Ohio Department of Transportation. During the study, a number of thermoplastic pipe structures under Ohio's highways were inspected and rated. One of the thermoplastic pipe structures was a 0.61‐m (24‐inch) diameter corrugated high‐density polyethylene (HDPE) pipe under State Route 145 in Noble County, Ohio. What was unique about this pipe structure was that it was the oldest thermoplastic pipe culvert in service in Ohio. The pipe was installed under a shallow cover in 1981. The Ohio University team visited the culvert site in 2004 and inspected the pipe structure thoroughly. It was inspected again in June of 2010. Drainage water entering the culvert was acidic, indicating the influence of a nearby surface coal mining operations. The pipe structure had moderate amounts of deflection under the roadway, but overall it appeared to be in satisfactory conditions. In 2004, a short pipe section was taken from the outlet end to determine if the pipe material had degraded over the years due to constant exposure to UV light and acid mine drainage. A series of tensile strength and density tests were performed according to industry standard test methods. Test results showed that the thermoplastic pipe material experienced little aging. Finally, a course of actions was recommended for the HDPE pipe structure based on a basic risk assessment analysis.

Select this Article		A Comprehensive Load Test on Prestressed Concrete Piles in Alluvial Clays and Marl in Savannah, Georgia Yong Tan, Ph.D. and Guoming Lin, Ph.D., P.E., F. ASCE Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000305 Posted ahead of print 20 October 2011 Full Text: \| Download PDF
	+ -	Show Abstract This paper introduces a comprehensive full‐scale pile load test program on 457‐mm (18‐inch) square prestressed concrete (PSC) piles in Savannah, Georgia, USA. The program consisted of pile driving analyzer (PDA) testing during initial pile driving and restrikes, Statnamic tests, static axial compression load tests, and reciprocal lateral load tests. Based on the interpretation of the test data, some important findings were obtained: (1) the alluvial clays in Savannah can only provide very limited resistance; (2) the time‐dependent pile capacity gain after pile driving (i.e., setup effect) was approximately proportional to the pile embedment length into the Marl formation; (3) the estimated equivalent static pile capacities from the Statnamic tests were comparable to those from the static axial load tests; (4) the Marl formation is a competent bearing stratum for piles; (5) the potential degradation of pile concrete stiffness due to pile driving should be accounted for in pile capacity analysis; and (6) the piles exhibited stiffer response under the monotonic lateral loading condition than the cyclic lateral loading condition. Finally, predictions on both axial and lateral pile capacities, using the soil parameters derived from the instrumentation data and back‐analysis of the pile load tests, were compared with the corresponding pile load test results. The comparisons demonstrate that in combination of the static bearing capacity formulae and the LPILE program, the developed soil models can make reliable predictions on both the vertical and lateral behaviors of the PSC piles driven through the soft alluvial clays to end bearing in the Marl formation.

Select this Article		Performances of Large‐Diameter Cast‐In Place Concrete Pipe Pile and Pile Group under Lateral Load Han‐Long Liu, Gang‐Qiang Kong, Aff. M. ASCE, Xuan‐Ming Ding, and Yu‐Min Chen Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000304 Posted ahead of print 20 October 2011 Full Text: \| Download PDF
	+ -	Show Abstract Large‐diameter cast‐in place concrete pipe pile (referred to as PCC pile) is widely used for pile foundation and pile‐supported embankment over soft clay in China. However, studies on PCC pile‐soil reactions (p‐y curves) or performance of pile groups under lateral load are not widely reported. A large‐scale model test of a single PCC pile under lateral load is carried out, and its lateral bearing capacity, bending moment, and p‐y curves are measured and analyzed. The deflection and bending moment of this PCC pile is calculated by the p‐y curves method and modified pile modulus using LPILE software. Three‐dimensional numerical analyses are conducted using ABAQUS software. The reliability and accuracy of the numerical simulation model are verified by comparing with the results of the large‐scale model test and LPILE calculation. The distribution of deflection and bending moment along the pile, and pile group efficiencies of PCC piles are comparatively analyzed with those of a drilled shaft which has the same concrete volume. Then, the lateral performance of PCC pile‐supported embankment influence factors are analyzed and discussed. The result shows that PCC piles under lateral load can be calculated by p‐y curves developed for drilled shaft and modified pile modulus using LPILE software. It also shows that PCC pile‐supported embankment is more cost‐effective than conventional pile (solid circular section pile) supported embankment.

Select this Article		Buckling Analysis of a Long‐Span Roof Structure Collapsed during Construction N. Augenti and F. Parisi Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000302 Posted ahead of print 18 October 2011 Full Text: \| Download PDF
	+ -	Show Abstract Numerical simulation of damage and collapse mechanisms suffered by engineering structures can be an effective tool for a quantitative assessment of their causes. Large displacement inelastic analysis may be required in the case of highly flexible structures such as steel roofs which frequently experience large failures or even collapse owing to buckling. This paper deals with the collapse of a long‐span steel roof structure which fell down suddenly during construction as a result of an out‐of‐plane buckling phenomenon induced by a gust of wind. Forensic investigations were carried out on behalf of the judicial authority in order to identify the causes of the accident. Based on detailed information gathered from site surveys and project documents, a three‐dimensional numerical model of the as‐built structure was created and buckling analyses were performed to assess the safety level at the moment of the collapse. The as‐built structure was braced through some purlins and steel cables fixed at the ground level. Structural stability was also investigated under further modeling assumptions to compare the effectiveness of several bracing systems in preventing the collapse. Analysis results showed that the as‐built structure was in an unstable equilibrium condition when the wind breeze occurred. Temporary bracing elements installed on the structure instead of concentric roof braces were not sufficient to ensure the overall stability.

Select this Article		A Sustainable Approach for Optimal Steel Sheet Pile Structure Assessment, Maintenance and Rehabilitation Kevin L. Rens, P.E. M. ASCE, Rui Liu, and Stuart D. Foltz Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000301 Posted ahead of print 18 October 2011 Full Text: \| Download PDF
	+ -	Show Abstract An improved steel sheet pile (SSP) inspection procedure is proposed in this paper, which couples the field inspection condition index (CI) methodology previously developed by the U.S. Army Corps of Engineer with reliability assessments to quantify the life‐cycle costs and environmental impacts associated with various maintenance and repair (M&R) scenarios. M&R strategies over the analysis period (from present to the end of the structure's lifetime) are determined through reliability assessment for structures with relatively low CI. The level of maintenance activity is then to be determined by the life cycle cost analysis and environmental life cycle assessment of M&R alternatives. The optimal M&R alternative is the one with the least cost and minimum environmental impacts. Using these methodologies, the SSP structure owners will gain improved capabilities to monitor the current conditions of SSP infrastructure and prioritize structures that will require sustainable M&R. Further research is proposed to collect real field inspection data and M&R records that can be used to estimate the reliability more accurately. In addition, the methodology developed for this relatively simple type of structure can be extended to more complex and critical structural systems such as gates, valves, and other components making up lock, dams and other related navigation facilities.

Select this Article		Construction Related Accidents in the Yucatan Peninsula, Mexico Rómel G.Solís‐Carcaño and Carlos E. Arcudia‐Abad Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000300 Posted ahead of print 18 October 2011 Full Text: \| Download PDF
	+ -	Show Abstract Construction activity generates important economic contributions to a country's economy and provides a source of employment for a large workforce; particularly in under‐developed countries. The unique characteristics that differentiate the construction industry from most others also propitiate a greater incidence of work‐related accidents. This work describes twenty two cases of accidents which took place in the Yucatan Peninsula where a migratory phenomenon has led to an increased demand for construction. This industry, therefore, has become an important source of employment and has stimulated the participation of companies from outside the state. The risks and subsequent consequences were studied and analyzed within a context of projects that were not particularly complex or of great height, and in which a low level of technology was used. These factors notwithstanding, results showed a high incidence of serious accidents. Based on an analysis of prediction and severity, it was possible to identify the principal conditions requiring urgent improvement in construction work risk prevention within the context previously mentioned.

Select this Article		Crack Survey in Unreinforced Concrete or Masonry Abutments in Short and Medium Span Bridges Reza Akbari Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000298 Posted ahead of print 18 October 2011 Full Text: \| Download PDF
	+ -	Show Abstract One of the most important tasks of a civil engineer as a bridge inspector is the structural assessment of cracks on bridge decks and their supporting structure. Although the work seems have a low value, the financial impacts on the bridge owners of getting it wrong can be significant. This paper summarizes what every civil engineer working as a bridge designer or inspector should know about undertaking and interpreting crack surveys in typical unreinforced concrete or masonry abutments in short and medium span bridges. A methodology is introduced that may be used to increase the validity and reliability of all decisions concerning the crack significance and associated remedial works.

Select this Article		In‐Service Performance Evaluation of a Cable Median Barrier System on Interstate Highways Shuo Li, Scott Newbolds, Karen Zhu, and Holly Menne Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000297 Posted ahead of print 18 October 2011 Full Text: \| Download PDF
	+ -	Show Abstract Under an Experimental Features Study (EFS) requested by Federal Highway Administration (FHWA), the Indiana Department of Transportation (INDOT) installed a proprietary cable median barrier system, i.e., the Brifen 4‐rope wire rope safety fence (WRSF), to assess issues in installation, maintenance, and repair of this WRSF system, and to evaluate its in‐service performance. The WRSF system was installed at two different sites, respectively. A total of 157 median crashes were examined to evaluate the safety performance of the WRSF system in terms of the effectiveness in intercepting errant vehicles and crash outcomes. Field visits were conducted to identify possible improvements to the layout of the WRSF system according to the roadway configurations. The construction and repair costs were examined to provide useful information for cost‐effectiveness analysis. Models were developed to enable an in‐situ estimate of the damage to the WRSF system after each crash. This paper presents the process and findings for the field installation, safety evaluation, and cost analysis.

Select this Article		Fire Impact and Passive Fire Protection of Infrastructure: State of the Art Michael T. Davidson, A. M. ASCE, Issam E. Harik, M. ASCE, and Douglas B. Davis, S.E., M. ASCE Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000295 Posted ahead of print 10 October 2011 Full Text: \| Download PDF
	+ -	Show Abstract Built infrastructure in the United States is generally susceptible to damage or collapse if subjected to severe fire conditions, such as those associated with the burning of a fully‐loaded gasoline tanker truck. Due to the importance and heavy use of transportation systems within the US, it is critical that susceptibilities to fire damage are investigated and mitigated to reduce the potential for substantial life‐safety and economic losses. The need for infrastructure fire protection is heightened by the frequency of collapse of infrastructure components (e.g., bridge superstructures) as part of severe fire incidents. However, fire protection of infrastructure remains a developing area. Presented in this paper is the state of the art in passive fire protection of transportation structures. More specifically, the impacts of high intensity fires on existing infrastructure and commonly used structural materials are reviewed. Additionally, design standards that provide means of assessing fire safety levels for passively protected transportation structures are reviewed, and the capabilities of existing fire protection materials available for use in transportation structures are assessed. Given the diverse nature of transportation structures located within the US, this paper is organized such that state of the art fire‐safety aspects are emphasized for two major types of transportation systems: tunnels and bridges.

Select this Article		Early‐Age Temperature and Strain in Basement Concrete Walls: Field Monitoring and Numerical Modeling Jikai Zhou, Xudong Chen, and Jian Zhang Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000294 Posted ahead of print 10 October 2011 Full Text: \| Download PDF
	+ -	Show Abstract Early age cracking of base restrained concrete walls is a common problem. To provide the owner with an early warning of in‐place quality problems resulting primarily due to thermal and shrinkage effects, it is helpful to apply monitoring and analytical techniques to examine the early age behavior of basement concrete walls. In this paper, the temperature and strain monitoring on a basement concrete wall is conducted. Major factors that contribute to the early‐age behavior of concrete walls constructed in cold weather are evaluated using analytical models along with measured field data and finite element modeling. The results show that the monitoring process eliminated much of the guesswork frequently associated with basement concrete walls constructed in cold weather. Temperature varies laterally within the wall. The strain remains unchanged after six days with formwork removal. And the numerical predictions for strains and temperature are in agreement with the measured results, during both the cooling phase and the heating phase. This analytical method can be applied to newly constructed basement walls since they are often built several weeks after the slab foundation.

Select this Article		Validation of a Construction Process Using a Structural Health Monitoring Network T. R. Nunez, R. L. Boroschek, and A. Larrain Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000293 Posted ahead of print 26 September 2011 Full Text: \| Download PDF
	+ -	Show Abstract A structural health‐monitoring (SHM) network was installed during the construction of a 56‐story frame‐wall concrete building with a height of 196 [m]. The SHM network recorded the vibrations produced by ambient, construction and earthquake excitations. The vibrations were used to identify the natural periods, mode shapes and damping ratios of the structure every ten minutes for six consecutive months and at five specific stages of the construction process during a two‐year period. The identified modal parameters were used to validate the construction process and the computer design model by comparing different adaptive computer models that corresponded to the progress in construction. Maximum differences of 14% between measured and analytical model natural period were obtained, and correlation to modal shapes were close to 95%, which indicates a good approximation of the predictive design computer model. The experimental techniques also allowed for the direct measurement of the energy dissipation properties of the building. For the low amplitude vibrations, the modal damping ratio ranges from 0.7% to 1.6% for the largest natural periods. The occurrence of the 2010 Central‐South Chile earthquake (magnitude Mw=8.8) also allowed for the comparison of the dynamic properties before and after an extreme loading event. A visual inspection of the building indicates an acceptable correlation between the minor damage observed and changes in the modal parameter values. The continuous monitoring of the dynamic properties of this permanently changing building proves to be an excellent tool for the verification of design models and quality assurance in construction control.

Select this Article		New Design Method for the Production Tolerances of Concrete Tunnel Segments S. H. P. Cavalaro, C. B. M. Blom, A. Aguado, and J. C. Walraven Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000291 Posted ahead of print 23 September 2011 Full Text: \| Download PDF
	+ -	Show Abstract Some damages observed in tunnels constructed with tunnel boring machines are caused by contact deficiencies between segments, which are the result of the sum and accumulation of several types of tolerances. Since the relation between the tolerances, the contact deficiencies and the structural damage is not quite clear, the segmented lining is usually designed to meet very tight tolerances. The existing tolerance recommendations consist mostly of extrapolation of tolerances applied to other types of concrete structures with different characteristics. This explains the wide variation of production tolerances found in the literature with different repercussion on the cost of molds and on the performance of the structure. The first part of this study shows the relation between structural damage and contact deficiencies. The second part of the study explains how the contact deficiencies found in practice are generated by the tolerances. Finally, a general design method is proposed for the estimation of the production tolerances. Based on that, general recommendations are derived about the maximum admissible production tolerance used to limit the incidence of structural damage.

Select this Article		A Retrospective Analysis to Identify Trends in Forensic Research Rebecca Macdonald, P.E., S. M. ASCE, W. Edward Back, Ph.D., M. ASCE, and Philip W. Johnson, Ph.D., P.E., M. ASCE Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000290 \| Cited 1 time Posted ahead of print 23 September 2011 Full Text: \| Download PDF
	+ -	Show Abstract This paper provides a comprehensive summary of forensic research trends as presented in American Society of Civil Engineer's Journal of Performance of Constructed Facilities (JPCF). The paper reports the results of a 24‐year analysis of JPCF published literature between 1987 and 2010. The journal continues to serve as a primary resource for published literature in the field of engineering forensics and provides a recorded history of our recognition and understanding of important lessons learned. Interesting facts were revealed that provide insights for practitioners and academia alike. The investigation indicates a wide participation of engineering disciplines, an increasing number of new topics, innovations, and proactive forensic methodologies, extensive interdisciplinary collaboration, and a significant increase in international contributions. This study may serve as a basis for defining the history and breadth of forensic engineering and for understanding the international relevancy and regional interest in the diverse subject matter. Increased acceptance, dissemination, and participation in forensic engineering is evident and should be encouraged and sustained as part of engineering curricula, investigative research, and professional practice.

Select this Article		Experimental Performance of Steel Beams under Blast Loading Amr A. Nassr, A. Ghani Razaqpur, Michael J. Tait, Manuel Campidelli, and Simon Foo Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000289 Posted ahead of print 23 September 2011 Full Text: \| Download PDF
	+ -	Show Abstract In this study the dynamic response of typical wide‐flange steel beams was experimentally evaluated under blast loading. A total of thirteen beams were field tested using live explosives, where the charge size ranged from 50 to 250 kg of ANFO and the ground stand‐off distance from 7.0 to 10.3 m. Blast wave characteristics, including incident and reflected pressures were recorded. In addition, time‐dependant displacements, accelerations, and strains at different locations along the steel members were measured, and the post‐blast damage and mode of failure of the test specimens were observed. The blast load characteristics were compared with those obtained using the Technical Manual UFC 3‐340‐02 results. The displacement response results were used to validate the results obtained from a nonlinear dynamic analysis based on Single‐Degree‐of‐Freedom (SDOF) model. Results showed that the UFC 3‐340‐02 pressure predictions compare reasonably well with the measured pressure in the positive phase in terms of both the peak pressure and overall time variations. The SDOF model predicted reasonably well the maximum displacements of beams in the elastic range, but it overestimated them in the plastic range.

Select this Article		Soil‐Structure Interaction and Failure of Cast‐Iron Subway Tunnels Subjected to Medium Internal Blast Loading Huabei Liu, M. ASCE Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000292 Posted ahead of print 23 September 2011 Full Text: \| Download PDF
	+ -	Show Abstract The threat of terrorist attack on subway system using explosives intensifies considerably in recent years. Explosion inside subway tunnels may lead to the failure of subway structures and result in further socioeconomic losses. Specifically, the century‐old single‐track cast‐iron subway tunnels in cities like New York and London are very vulnerable to this type of attack. In this study, an explicit dynamic Finite Element procedure was developed to carry out extensive numerical simulation investigating the soil‐structure interaction and failure of cast‐iron tunnels in saturated soils subject to internal explosions using medium amount of explosive (80 kg TNT) that might be perpetrated by terrorists. The stress path and damage mode of these tunnels subjected to internal blast loading were firstly investigated, based on which the damage of cast‐iron tunnel lining was simulated using hardening elasto‐plastic model considering shear damage. The study aims to better understand the soil‐structure interaction and its relation to lining damage of cast‐iron subway tunnels under internal blast, and to investigate the influences of several critical parameters on the lining failure, including compressibility of saturated soil, brittleness of lining materials, specific impulse of blast, and strength of soil‐lining interface. The study found that ground‐tunnel interaction was one of the governing factors determining the damage of tunnel lining under medium internal blast loading by providing the necessary confinement to resist internal blast loading and by absorbing blast energy with its plastic shear deformation. Lining damage was mainly triggered by the tensile hoop stress due to large inertia and dynamic forces in the radial direction of tunnel and it may exhibit a progressive pattern in the vibration phase. Soil compression significantly influenced the damage of tunnel under internal blast loading. The damage was more severe with compressible saturated ground.

Select this Article		Experimental Study on the Progressive Collapse Resistance of a Two‐Storey Steel Moment‐Frame Junling Chen, Xin Huang, Renle Ma, and Minjuan He Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000287 Posted ahead of print 17 September 2011 Full Text: \| Download PDF
	+ -	Show Abstract In this study, the progressive collapse resistance of a two‐storey steel moment‐frame was investigated after the sudden removal of a perimeter column in the first floor through an experimental study. Two finite‐element models with and without concrete slabs were developed and compared with the experimental results. The results indicate that the numerical model with slabs agrees well with that of the experiment and the concrete slabs play a significant role during the process of load redistribution. After the removal of the column, the partial loads previously carried by the removed column were transferred to its adjacent columns by the slabs. In addition, the concrete slabs and steel beams composed composite beams through shear connectors to resist the loads after the removal of the column. As a result, the stresses in the beams and the vertical displacements above the removed column were reduced significantly.

Select this Article		Experimental and Analytical Assessment on RC Interior Beam‐Column Subassemblages for Progressive Collapse Qian Kai and Bing Li Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000284 Posted ahead of print 1 September 2011 Full Text: \| Download PDF
	+ -	Show Abstract Experimental and analytical studies carried out on a reinforced concrete (RC) moment resisting frame after it is subjected to the loss of its ground storey exterior column is presented in this paper. Four full‐scale interior beam‐column subassemblages with varying degrees of non‐seismic detailing were subjected to a monotonic loading regime to simulate the effects of re‐distributed gravity loads on the subassemblage after the loss of an exterior ground column. The variables in the test specimens include the beam longitudinal reinforcement ratios and the spacing of the transverse reinforcement within the beams, columns and joints. Load‐displacement relationships, crack development patterns and failure mechanism obtained from the tests are also discussed. The finite element models are validated by comparing the results with the experimentally obtained data. Parametric studies are then performed to study the influence factors, such as beam transverse reinforcement ratio, and incorporation of an additional exterior beam‐column element and slab, on the global behavior of the subassemblages.

Select this Article		Management and Maintenance Scheduling of Infrastructural Facilities ‐ A Road Map N. Lakshmanan, K. Ravisankar, K. Muthumani, T. S. Krishnamoorthy, K. Ramanjaneyulu, N. Gopala Krishnan, and Nagesh R. Iyer Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000283 Posted ahead of print 1 September 2011 Full Text: \| Download PDF
	+ -	Show Abstract A four stage procedure for effective management and maintenance scheduling for infrastructural facilities is presented. The structure/component that needs immediate attention would be identified during the first stage. The second stage investigations would reveal local or global damage and also the location of damage, based on principles of damage assessment. Non‐destructive testing and evaluation forms the third stage. In the last stage repair and remedial measures are carried out, which will be followed by testing if necessary. Out of the case study examples presented, two are specific to third and fourth stage evaluation only, while one case study example is explained in full.

Select this Article		Effects of Backfill Soil on Excessive Movement of MSE Wall M. S. Hossain, G. Kibria, M. S. Khan, J. Hossain, and T. Taufiq Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000281 Posted ahead of print 18 August 2011 Full Text: \| Download PDF
	+ -	Show Abstract The use of mechanically stabilized earth (MSE) retaining wall has gained popularity as an alternative to conventional cast in place concrete walls. The construction of mechanically stabilized earth wall is cost effective, requires less site preparation and technically more feasible compared to conventional concrete retaining wall. However, use of backfill with high fine content and their poor drainage behavior can cause excessive wall movement or even failure. The current paper presents the case study of a MSE wall located at state highway 342 (SH 342) of Lancaster, Texas. The top of the MSE wall has moved as much as 300 mm to 450 mm only five years after construction. An extensive site and laboratory investigation testing program was conducted to determine the possible causes of MSE wall movement. The site investigation included soil test boring and resistivity imaging (RI). Perched water zones were identified at few locations in the backfill area using RI. The bulging of the MSE wall facings was observed where the perched water zones were located. Laboratory testing of the collected soil samples were conducted to determine the characteristics of backfill soil. The test results indicated the backfill soil to be clayey sand (SC) according to Unified Soil Classification System (USCS). Based on the test results and analyses, it was determined that the presence of high fine content may have caused the excessive movement of the MSE wall. The movement of the MSE wall was also modeled using finite element program PLAXIS, and presented in this paper. The actual movement of the MSE wall and obtained movement from the model were in good agreement.

Select this Article		Behavior of Slender Steel‐Concrete Composite Columns Wrapped with FRP Jackets Kian Karimi, S. M. ASCE, Wael W. El‐Dakhakhni, M. ASCE, and Michael J. Tait, M. ASCE Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000280 Posted ahead of print 18 August 2011 Full Text: \| Download PDF
	+ -	Show Abstract This paper studies the influence of slenderness on the behavior of steel‐concrete composite columns encased in Fiber Reinforced Polymer (FRP) jackets. The composite columns are composed of steel I‐sections that are partially‐encased by concrete and fully‐wrapped with epoxy‐saturated glass and carbon FRP (GFRP and CFRP) sheets. A total of nine specimens were tested with different slenderness parameters and heights ranging between 500 mm and 3,000 mm. The confining pressure provided by the FRP jacket and the composite action between the constituent materials resulted in an enhanced compressive behavior of the composite columns. The compressive strength, elastic axial stiffness and energy dissipation capacity of the composite columns increased by a ratio of up to 5.2, 2.5 and 14.0, respectively, compared to that of their bare steel columns counterparts. A capacity curve, which shows the compressive strength of the composite columns for various slenderness parameters, was developed based on the experimental results.

Select this Article		Investigation of Vibration Effects Due to Driving of PHC Pipe Piles Yong Tan and Hongliang Lan Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000278 Posted ahead of print 17 August 2011 Full Text: \| Download PDF
	+ -	Show Abstract In order to ensure the safety of the adjacent 16.7‐m high concrete frame structures (cooling towers) and buried pipelines in service during installation of 83 prestressed high‐strength concrete (PHC) pipe piles, the behaviors of the ground, buried pipelines and the cooling towers were monitored by a comprehensive instrumentation program. The field measurements included: (1) time histories of particle velocities and the corresponding Fourier spectra in three mutually perpendicular directions at different pile penetration depths; and (2) vertical and horizontal movements of the buried pipelines due to pile installation. Based on the analysis of the field data, the following major findings were obtained: (1) different from driving of prestressed concrete piles or cast‐in‐situ piles, vibration velocity in the vertical direction was not greater than those in the plane during PHC pipe pile driving; (2) the amplitudes of peak particle velocities (PPV) were relatively independent of pile penetration depths due to the complex soil conditions; (3) both the ground and the concrete structure experienced primarily high‐frequency vibrations, which attenuated rapidly over time; (4) during the pile driving, only slight vibration amplification was observed at the upper levels of the existing concrete frame structure as the result of soil‐structure interaction. The concrete structure had a much wider frequency band (around 0 to 300 Hz) than the ground (around 0 to 100 Hz); and (5) the method of installing piles close to the existing facilities before installing those distant away effectively mitigated the potential adverse effects on the buried pipelines.

Select this Article		3D Terrestrial LiDAR for Operational Bridge Clearance Measurements Christopher Watson, Shen‐En Chen, Haitao Bian, and Edd Hauser Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000277 Posted ahead of print 17 August 2011 Full Text: \| Download PDF
	+ -	Show Abstract This paper reports the outcomes of a study of the vehicle crossing effects on terrestrial LiDAR scan on highway bridges for underclearance measurements. Ground‐based or vehicle‐mount terrestrial LiDAR scanners, which recreate the bridge structure as 3D point cloud of thousands of position data points, have been found to be ideal for bridge clearance measurements. To determine the effects of ambient overhead vehicle crossing and seasonal temperature variation on clearance measurements, periodic monitoring of the Harris Road Bridge has been conducted. A simplistic but practical correlation analysis is performed which shows that operational LiDAR scanning is a viable technique for bridge clearance measurements.

Select this Article		Using Fuzzy Failure Mode Effect Analysis to Model Cave‐in Accidents H. M. Al‐Humaidi and F. Hadipriono. Tan Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000276 Posted ahead of print 17 August 2011 Full Text: \| Download PDF
	+ -	Show Abstract Behavioral, managerial and technical problems cause construction injury accidents. Among these accidents, cave‐ins are some of the most frequently occurring. Mitigating hazards that result in cave‐ins is of great importance in managing and controlling excavation practices. This paper introduces a new conceptual risk‐mitigation tool that can be adopted to minimize cave‐in hazards and be employed as a quality‐control tool before and during excavations. It provides a list of hazards in ranked order from the most frequent to least frequent and most hazardous to least hazardous causes that managers should focus on and invest resources into. Precise risk evaluation for cave‐ins using traditional methods of Failure Mode and Effect Analysis (FMEA) can be challenging because the variables involved in cave‐ins are unique, and historical data is often incomplete. In construction, estimation of risk is based on severity, frequency of occurrence and likelihood of detection; management teams assess these factors prior to failure occurrences using subjective judgment expressed by linguistic values such as severe, very likely, etc. Such linguistic terms can be best modeled using fuzzy set theory. The traditional Failure Mode Effect Analysis (FMEA) method has been widely used to calculate a Risk Priority Number (RPN), which is a weighted assessment used to prioritize risk items. The calculation of the RPN is based on rating three variables: (1) severity, (2) frequency of occurrence and (3) likelihood of detection. The traditional RPN is the product of these variables. Implementation of FMEA for construction projects must be modified, since calculation of the RPN in construction projects is based on managerial experience using experiential, subjective expressions. The RPN is substituted for fuzzy rating calculation using alpha cuts and fuzzy arithmetic, to perform the fuzzy operations of the variables and to introduce a workable model of a Fuzzy Risk Priority Number (FRPN). For assessment purposes, the FRPNs are ranked. A numerical example is provided to illustrate the potential application of the proposed FFMEA and the detailed computational process of the FRPN. An application of the fuzzy failure mode and effect analysis is presented for the assessment of construction trenching safety risk. The FFMEA method introduced in this paper is intended to be used for (1) anticipating potential cave‐in accidents prior to their occurrence; (2) assessing risks associated with excavation work; (3) providing a list of likely cave‐in accident scenarios associated with excavation work in advance; and (4) preparing solutions and taking corrective actions before cave‐in accidents occur.

Select this Article		Assessment of Long Term Performance of a 50 Year Old Jetty in South of Iran Masoud Moradian, Mohammad Shekarchi, Mahdi Aabdollah, and Reza Alidadi Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000275 Posted ahead of print 17 August 2011 Full Text: \| Download PDF
	+ -	Show Abstract A detailed investigation was carried out on a 50 year old reinforced concrete jetty in a commercial port of Iran to assess the long term performance as well as the structural condition. Destructive and non‐destructive tests such as carbonation depth, electrical resistivity, chloride diffusion, X‐Ray diffraction, compressive strength and water absorption were performed. The results revealed that good quality of the concrete has protected reinforcement from corrosion. However, structural analysis showed minor weakness in some elements of the jetty, thus consulting engineers finally decided to strengthen some elements with fiber reinforced polymers (FRP).

Select this Article		Integral Lifting and Seismic Isolation Retrofit of Great Hall of Nanjing Museum: Case Study Tong Guo, Erjun Wu, Aiqun Li, Longwu Wei, and Xingping Li Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000273 Posted ahead of print 3 August 2011 Full Text: \| Download PDF
	+ -	Show Abstract This paper presents the integral lifting and seismic isolation retrofit of the great hall of Nanjing Museum, a seventy‐eight‐year‐old cultural and historical building. Due to the need for extension, the great hall of the Nanjing Museum needs to be lifted by 3.0 meters. The total building area for lifting was 4,830m² with a total of 161 lifting points, which makes this project quite challenging and also the largest one among others. Moreover, seismic isolation retrofit was utilized to improve the seismic performance of the translocated building. Details of the integral lifting and the seismic retrofit are presented in this paper, which include: (1) the load underpinning system; (2) the spatial strengthening truss system; (3) the lifting control system; and (4) the base isolation using laminated rubber isolators. The entire lifting system performed well and the main construction was finished within five months. Seismic time‐history analyses were further performed to evaluate the effect of the seismic isolation. It is observed that seismic responses of the museum are significantly reduced after retrofit.

Select this Article		Development of a Road Monitoring and Reporting System Based on Location‐Based Services and Augmented Reality Technologies Jia‐Ruey Chang, Hui‐Mi Hsu, and Sao‐Jeng Chao Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000272 Posted ahead of print 3 August 2011 Full Text: \| Download PDF
	+ -	Show Abstract To provide certain level of serviceability, road authorities need to perform appropriate and timely maintenance and rehabilitation (M&R) activities. However, the vast expanse and different deterioration properties of road systems greatly increase the complexity of M&R activities. Due to lack of funding and resources, it is almost impossible for road engineers to monitor every road and to promptly maintain and rehabilitate any defects that have been identified. Therefore, the monitoring and reporting of defects contributed from the public domains are becoming indispensable. For several years, location‐based service (LBS) has been applied to mobile devices with mobile positioning functions to provide users with location‐specific services. Augmented reality (AR) can support users in manipulating virtual objects in real environments. In this study, a road monitoring and reporting system (RMRS) is developed including a mobile RMRS (an Android application, or Android ‘APP’) on smartphones and a web‐based RMRS by integrating LBS and AR technologies. By using LBS and AR technologies, the time and costs of M&R activities can be significantly decreased since routes of M&R activities can be planned in advance and the neighboring defects can be instantly identified and processed, which conforms exactly to the current policies of the “The Public Oversight of Public Works Projects” and “Smooth Roads Project” in Taiwan. By using field data from Ilan County in Taiwan and considering the indefinite delivery contract (IDC), different strategies for M&R operation derived from the mobile and web‐based RMRSs are analyzed. The results are presented to demonstrate the system's benefits, costs, and feasibility.

Select this Article		Performance of Metal‐Plated Wood Joints Exposed to Periods of Soaking Moisture Primus V. Mtenga, Kamal S. Tawfiq, and Michelle Rambo‐Roddenberry Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000271 Posted ahead of print 3 August 2011 Full Text: \| Download PDF
	+ -	Show Abstract Metal‐plated wood truss systems may be rained‐upon during the construction phase, resulting in the soaking of the connections. In this paper, the results of an investigation of the behavior of metal‐plated wood joints subjected to periods of soaking are presented. The wetting regimes included: 1) 4‐hour shower, 2) alternating cycles of a period of shower wetting followed by a period of no shower, and 3) 24‐hour soaking in a water tank. Results of tests conducted after wetting and after wet‐dry cycles were compared to results of dry control tests. The results show the wet joints lost over 40 percent of their load carrying capacity in all three wetting regimes. Upon drying, the strength loss was about 10 percent. Likewise, the stiffness of the joints deteriorated, with stiffness loss ranging from 12 to 37 percent. In contrast to the load carrying capacities, there were insignificant recoveries in joint stiffness upon the drying of the specimen, with additional loss of stiffness during the drying process in one of the groups investigated. The results of this study suggest the need to warn against severe wetting or to compensate for this probability of occurrence in truss design standards.

Select this Article		Loss Analysis of Wood Frame Buildings during Hurricanes. II: Loss Estimation John W. van de Lindt, M. ASCE and Thang Nguyen Dao, A. M. ASCE Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000270 Posted ahead of print 3 August 2011 Full Text: \| Download PDF
	+ -	Show Abstract This is the second paper in a set of companion papers. The first paper focused on modeling the hurricane hazard and the methodology to compute the volume of rainwater entering a roof system during a hurricane. In this second paper a methodology to probabilistically compute losses beginning with the type and location of damage and volume and location of rainwater intrusion into the roof system is explained. The ability to identify each contribution to damage and monetary loss is a necessary condition for development of performance‐based wind engineering, thus providing the impetus for this second paper. The methodology summarized in this paper is capable of tracking damage and the individual damageable component contributions to the total loss probability. An illustrative example that compares losses for the same light‐frame wood residential structure introduced in the first paper is presented. In addition, both damage and loss probability distributions are presented for each room in the structure, as well as for each damageable component. The results are felt to be reasonable and align qualitatively with logic considering the size of the hurricanes and geographical location of the structure. The approach has applicability in design code refinement and development, sensitivity studies for improved building products, and land use and planning investigations.

Select this Article		Loss Analysis for Wood Frame Buildings during Hurricanes I: Structure and Hazard Modeling Thang Nguyen Dao, A. M. ASCE and John W. van de Lindt, M. ASCE Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000269 Posted ahead of print 3 August 2011 Full Text: \| Download PDF
	+ -	Show Abstract Hurricanes present a serious financial threat to the Gulf Coast and Eastern Sea Board of the United States. This paper is the first in a set of companion papers that detail a comprehensive mechanistic loss model for wind and rainwater intrusion damage to light‐frame wood buildings. In this paper the structural and hazard modeling for a passing hurricane is explained and demonstrated. The structural model consists of a nonlinear nail model integrated into a finite element model and the hazard model is developed using a combination of existing wind tunnel data, and a rainwater intrusion model. A methodology to compute the rainwater entry volume is presented. The approach differs from previous methods in that it allows any time period to be examined by dividing the hurricane passage period into smaller increments of time and allowing both load and resistance to change from time period to time period. Thus, the time and location of damage and rainwater intrusion is known. The companion paper to this paper utilizes the volume of rainwater calculated herein and presents a systematic mechanistic approach to damage state modeling and related financial loss.

Select this Article		Evaluation of Unknown Foundation Depth Using Different NDT Method M. S. Hossain, M. S. Khan, J. Hossain, G. Kibria, and T. Taufiq Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000268 Posted ahead of print 3 August 2011 Full Text: \| Download PDF
	+ -	Show Abstract Many of the older bridges in the United States have no original contract documents available and about 26,000 bridges that are rated as scour critical have unknown foundation conditions. Thus, no information is available regarding the type, depth, geometry or material of these scour critical bridge foundations. The unknown bridge foundations pose a significant problem to bridge owners because of safety concerns. The current paper presents the determination of an unknown bridge foundation depth at Forth Worth, Texas, US. The bridge was supported by driven steel H‐piles. Three Non Destructive Testing (NDT) techniques were utilized: (1) Parallel Seismic (PS) method, (2) Sonic Echo (SE) method & (3) Resistivity Imaging (RI). The main objective of this current study was to compare the suitability of NDT techniques to determine the unknown bridge foundation depth. Based on the field test results, both Parallel Seismic and Resistivity Imaging method provided foundation depth close to actual foundation depth. However, Sonic Echo test was determined to be not suitable for determining the unknown steel H‐pile depth.

Select this Article		Enhanced Modeling of Steel Structures for Progressive Collapse Analysis Using Applied Element Method Ahmed Amir Khalil Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000267 Posted ahead of print 3 August 2011 Full Text: \| Download PDF
	+ -	Show Abstract This paper studies performing progressive collapse analysis for steel structures using the requirements of recent codes released by the United States Department of Defense and the General Services Administration. Based on review of the code requirements, nonlinear dynamic progressive collapse analysis results in a more uniform factor of safety than linear static analysis. The Applied Element Method in structural analysis is proposed as an efficient alternative for performing progressive collapse analysis. A case study is undertaken where the results of progressive collapse analysis using traditional finite‐element‐method simplifications are compared to the results from the Applied Element Method in the analysis of a moment‐resisting steel frame. The case study shows that simplifications that are usually done in finite element analysis when studying traditional load cases can be over‐conservative when performing progressive collapse analysis. The results show that the use of the nonlinear dynamic Applied Element Method while taking into account the effect of secondary members such as slabs and secondary beams can lead to considerable savings in the total weight of the steel frame.

Select this Article		Taquezal Buildings in Nicaragua and Their Earthquake Performance Lisa Holliday, Ph.D., Thomas H. ‐K. Kang, Ph.D., P.E., M. ASCE, and Kyran D. Mish, Ph.D. Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000266 Posted ahead of print 3 August 2011 Full Text: \| Download PDF
	+ -	Show Abstract Taquezal is a common earthen building type in Nicaragua. It is constructed by building a wood frame and then packing the frame with mud to create thick earthen walls. The wood frame allows the structure to be constructed without the formwork (as required for rammed earth buildings) and without first constructing blocks (as adobe is generally constructed). The wood frame also allows a thinner wall than other earthen building types. Commonly taquezal roofs are made of timber framing and heavy clay tile roofs. Taquezal buildings are not engineered and therefore they are difficult to analyze with modern structural engineering methods. What is known about taquezal buildings is their performance during the 1972 Managua earthquake when nearly 10,000 people died and most of them were in taquezal buildings. This paper discusses taquezal as a structural system and applies engineering methods to this non‐engineered structure. It was found that taquezal buildings perform well during low to moderate earthquakes if well maintained. However, if the wood is not maintained and allowed to rot, this degrades the roof diaphragm and wall supports and performance is considerably diminished.

Select this Article		RDD Data Interpretation and Its Application on Evaluating Concrete Pavements for Asphalt Overlays Fujie Zhou, Sheng Hu, Dar‐Hao Chen, and Tom Scullion Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000265 Posted ahead of print 3 August 2011 Full Text: \| Download PDF
	+ -	Show Abstract The placement of an asphalt overlay is the most common method to rehabilitate existing concrete pavements. Reflective cracking, however, has been a serious problem with asphalt overlays for a long time. To prevent reflective cracking, it is critical to evaluate existing concrete pavements and identify the joints/cracks with poor load transfer efficiency (LTE) before placing an asphalt overlay. The most common equipment for this evaluation is Falling Weight Deflectometer (FWD). However, FWD testing is conducted only at discrete points and is time consuming. It is desirable to use the Rolling Dynamic Deflectometer (RDD) that can continuously characterize each slab and all joints and/or cracks (such as LTE). The RDD was developed in the 1990s at the Center for Transportation Research at Austin, Texas. The RDD is one of the few operational rolling deflection systems which provide continuous data to make project level decisions on rehabilitating concrete pavements. In contrast to the FWD, no RDD data analysis software is available. This paper discusses RDD data interpretation and its application on evaluating existing concrete pavement for asphalt overlays. First of all, some basics of RDD deflection data interpretation are discussed. Several common patterns within the RDD data are identified, and associated interpretation and limited verification are presented in this paper. The RDD deflection data measured before an asphalt overlay on Interstate Highway 20, Texas and the observed asphalt overlay performance (in terms of reflective cracking) are then presented, and the relationship between RDD deflection and reflective cracking rate is further investigated. Finally, guidelines for evaluating existing concrete pavements using RDD are proposed.

Select this Article		Earthquake Behavior of Berke Arch Dam Using Ambient Vibration Test Results Barış Sevim, Asst. Prof., Ahmet Can Altunişik, Asst. Prof., and Alemdar Bayraktar, Prof. Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000264 Posted ahead of print 3 August 2011 Full Text: \| Download PDF
	+ -	Show Abstract Berke Arch Dam is the highest arch dam constructed in Turkey. It has 201m dam height and 270m crest length. This paper describes Berke Arch Dam, its finite element modeling, ambient vibration testing, finite element model calibration and earthquake behavior before and after model calibration. Firstly 3D model of dam‐reservoir‐foundation interaction is developed to obtain analytical dynamic characteristics such as natural frequencies and mode shapes using ANSYS finite element program. In the analyses, reservoir water is represented by Lagrangian Approach. Then, ambient vibration tests are conducted on the dam along 4 days in May 2009 to obtain experimental dynamic characteristics. In ambient vibration tests, the sensitive accelerometers are placed the several point of the arch dam and signals are collected from accelerometers. Enhanced Frequency Domain Decomposition technique is used in the extraction of experimental natural frequencies, mode shapes and damping ratios. After that, 3D finite element model of Berke Arch Dam is calibrated using ambient vibration test results. Lastly, earthquake behaviors of initial and calibrated models of Berke Arch Dam are obtained using Adana‐Ceyhan Earthquake in 1998. It is observed that model calibration affects the results considerably.

Select this Article		Pervious Concrete Surface Characterization to Reduce Slip‐Related Falls J. T. Kevern, M. ASCE, G. W. King, and A. P. Bruetsch Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000263 Posted ahead of print 11 July 2011 Full Text: \| Download PDF
	+ -	Show Abstract This paper presents results from a unique study which employed biomechanical evaluation techniques to assess the slipping behavior of traditional and pervious concrete pavements under icy conditions. Gait motion analysis using embedded force plates, electromyography, and tracking videography were used to analyze subject mobility of on icy and wet pervious concrete. Results show that pedestrian contact pressure on pervious concrete is more than twice the pressure on traditional impervious concrete. In slippery conditions the pervious concrete specimens had more controlled gait cycles and reduced slipping. The unique surface characteristics combined with high permeability, reduces surface icing, suggesting that pervious concrete offers superior slip resistance in inclement weather.

Select this Article		Effect of Bottom Chord Extensions on the Static Flexural Stiffness of Open‐Web Steel Joists Onur Avci, Ph.D., P.E., M. ASCE and Thomas M. Murray, Ph.D., P.E., F. ASCE Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000262 Posted ahead of print 11 July 2011 Full Text: \| Download PDF
	+ -	Show Abstract Annoying floor vibrations, a growing issue in today's world of lighter structural members and low inherent damping because of modern office fit‐outs may also be significant in open web steel joist supported floor systems. In the presence of annoying floor vibrations from such systems, sometimes bottom chord extensions are installed in an attempt to stiffen the floor and correct the annoying vibrations problem. The study presented in this paper focuses on the effect of bottom chord extensions on the static flexural stiffness of joists under relatively light loads associated with occupant induced floor vibrations. Extensive analytical and experimental studies were conducted on single span and three span joist supported laboratory footbridges with different bottom chord extension configurations. Three dimensional finite element computer models were created to simulate and compare the results of the stiffness tests. Testing was done with a) the bottom chord extensions installed prior to concrete placement, b) all or part of the bottom chord extensions removed, and c) the bottom chord extensions reinstalled with jacking for the single span footbridge and without jacking for the three‐span footbridge. The primary objective of the study was to determine the possible increase in flexural stiffness when bottom chord extensions are installed in an attempt to reduce annoying floor vibrations. The experimental results for the two footbridges with bottom chord extensions installed after the concrete placement are compared to results when the bottom chord extensions are installed prior to concrete placement and to footbridges without bottom chord extensions. Results from the stiffness tests on a single span footbridge indicate that installing the bottom chord extensions to the joists after concrete placement and with the center of the span jacked up increases the flexural stiffness considerably, but not as much as installing the bottom chord extensions before the concrete placement. Similar results were found when bottom chord extensions were installed after concrete placement but without jacking on a three span footbridge. The magnitude of the increases in flexural stiffness is sufficient to consider the installation of bottom chord extensions as a remedy to stiffen a floor and reduce floor vibrations due to occupancy movements.

Select this Article		Strengthening of Horizontal Bracing on Progressive Collapse Resistance of Multi‐Storey Steel Moment Frame Junling Chen, Wenbing Peng, Renle Ma, and Minjuan He Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000261 Posted ahead of print 11 July 2011 Full Text: \| Download PDF
	+ -	Show Abstract In this study, the contribution of horizontal bracing to the resistance of steel moment frame against progressive collapse was investigated using the Alternate Path (AP) method. Nonlinear dynamic analyses of two frame models without and with horizontal braces were carried out in various cases. The dynamic nonlinear analytical results indicated that, compared with the model without braces, the displacements and rotation angles in the model with horizontal braces were much smaller due to the horizontal tie provide by the horizontal braces at the top storey. It was observed that the horizontal braces could transfer the vertical loads originally carried by the removed column to the adjacent columns. Also, the layout of horizontal braces was an effective means to enhance the resistance of the steel moment frame.

Select this Article		The Effect of Water on the Degradation of Gypsum Plaster Coatings: Inspection, Diagnosis and Repair F. Palha, A. Pereira, J. de Brito, and J. D. Silvestre Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000258 Posted ahead of print 16 June 2011 Full Text: \| Download PDF
	+ -	Show Abstract This paper presents an expert system designed to support the inspection and diagnosis of gypsum plaster coatings applied to partition walls and ceilings (interior gypsum plaster ‐ IGP). It includes a classification of the defects that may affect IGP and their probable causes, the correlation matrices amongst defects, and between defects and probable causes, and a classification of diagnostic methods and repair techniques suitable for each type of IGP defect. This inspection system was validated through standard IGP inspections undertaken on 119 walls or ceilings in 23 buildings located throughout Portugal. A statistical analysis of the results of the inspection is given which provides details on, in particular, the pathological problems related to the action of water on IGP, since the presence of moisture within or on the surface of IGP coatings was shown to affect the severity of the problems of inspected samples. The characteristics and frequency of occurrence of “dampness”, “biodeterioration” and “efflorescence and cryptoflorescence” are presented, together with the primary causes for their presence in the sample. The most suitable diagnostic methods, preventive measures and repair solutions prescribed for these defects are also analyzed in detail.

Select this Article		A Study on Bridge Scour Risk Assessment and Countermeasure Design A. Melih Yanmaz and Meric Apaydin Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000254 Posted ahead of print 16 June 2011 Full Text: \| Download PDF
	+ -	Show Abstract Statistical surveys conducted on investigation of reasons of bridge failures implied that majority of bridges have failed because of excessive scouring at infrastructural elements. A bridge crossing an alluvial river should therefore be designed properly with special reference to possibility of this action at piers and abutments. Upon construction of a bridge, its scour criticality should be examined regularly throughout the service life spans to take necessary actions promptly. The Federal Highway Administration of United States (FHWA) developed a methodology and its software named, HYRISK to evaluate annual risk of scour failure of an existing bridge in monetary values. A case study is carried out for a bridge crossing Fol Creek in Black Sea Region of Turkey using this methodology, which is integrated with additional assessment methods for checking conditions of bridge elements and channel in close vicinity. The scour criticality of the bridge corresponding to existing and possible future conditions is obtained and a feasible scour countermeasure is designed using HYRISK and an economic analysis.

Select this Article		Costs and Effectiveness of Flexible Pavement Treatments: Experience and Evidence Yuhong Wang, P.E., M. ASCE, George Wang, M. ASCE, and Neil Mastin, P.E., M. ASCE Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000253 Posted ahead of print 16 June 2011 Full Text: \| Download PDF
	+ -	Show Abstract The authors investigated the effectiveness and costs of preventive treatment techniques for flexible pavements. Based on survey results from 29 state DOTs, it was found that the expected pavement life extension caused by these treatments follows the order of thin HMA overlay, micro‐surfacing tied with chip sealing, slurry sealing, and crack filling/sealing. The reported costs follow the order of thin overlay, micro‐surfacing, chip sealing tied with slurry sealing, while costs of crack sealing/filling cannot be directly compared. The authors also analyzed data from 81 Long‐Term Pavement Performance Program (LTPP)'s SPS 3 experiments, which were specifically designed and constructed to study the effectiveness of pavement treatments. Based on paired t‐tests, it was found that all the treatments reduced IRI with statistical significance. The authors then pooled the data from all the control sections and created a “pseudo” control section and subsequently developed a linear regression model for it. By comparing the effects of treatments with this “pseudo” control section, the authors found that the approximate life extension of the pavement sections benefited from these treatments is: thin overlay for 5.4 years, chip sealing for 1.9 years, crack sealing for 1.7 years, and slurry sealing for 1.1 years.

Select this Article		Coupled Field Monitoring and Structural Analysis to Assess Scour Conditions Jennifer Righman McConnell, A. M. ASCE and Michael Cann, A. M. ASCE Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000252 Posted ahead of print 16 June 2011 Full Text: \| Download PDF
	+ -	Show Abstract This paper reports on the implementation of a relatively novel scour monitoring system that includes the ability to record substructure response to potential changes in scour conditions. The substructure instrumentation consists of tilt sensors installed at the top of each of two in‐water piers on an existing common configuration of steel I‐girder bridge that is currently the site of severe scour problems. The key focus of this paper is the structural analysis that was required in order to assess the significance of potential instrumentation readings resulting from these sensors. Two types of structural analysis were performed: a one‐dimensional pushover analysis to assess substructure stability and a three‐dimensional finite element analysis to evaluate superstructure performance as a result of movement to the substructure. As a result, the substructure displacements corresponding to unfavorable performance of the structure were determined in both types of analysis. The effects of scour on the superstructure are also used to draw attention to the need for a greater understanding of the consequences of scour.

Select this Article		Fire Resistance of a Damaged Steel Building Frame That Has Been Designed to Resist Progressive Collapse Spencer E. Quiel and Shalva M. Marjanishvili Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000248 Posted ahead of print 21 May 2011 Full Text: \| Download PDF
	+ -	Show Abstract In current practice, progressive collapse analysis typically includes two types of hazards: the initial hazard that causes localized damage and the subsequent response of the structure to bridge loads across the damaged areas (analysis referred to as alternate path method). However, little detailed information is available on a third type of hazard such as fire that typically follows the initial hazard. Prolonged exposure of a damaged structure to fire could be detrimental to the short‐term stability of that structure and may pose a significant threat to the safe evacuation of building occupants. This paper presents a study of the effects of fire following an extreme event (i.e. blast or impact) that causes failure of one column on the perimeter of a common steel building frame. The approach focuses on a steel structure that is designed to satisfy new US DoD guidelines and assumes that the extreme event not only damages one column but also damages active fire protection (i.e. sprinklers) in the vicinity of the structural damage. Results of this study include estimates of the time to collapse initiation and a correlation between the level of remaining passive fire protection (i.e. spray‐on fire resistive materials applied to the structural elements) and the collapse time. The goal of this study is to raise awareness of potential fire hazards that may follow extreme events and provide recommendations regarding evacuation times for occupants of damaged buildings under fire.

Select this Article		Seismic Performance Assessment of Masonry Tile Domes through Non‐Linear Finite Element Analysis S. Atamturktur and B. Sevim Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000243 Posted ahead of print 2 May 2011 Full Text: \| Download PDF
	+ -	Show Abstract This article discusses a combined analytical and experimental study on the non‐linear seismic performance of two Guastavino‐style masonry domes located in the U.S. The seismic performance of these masonry domes is simulated with non‐linear finite element (FE) models. To support the assumptions and decisions established during the development of the FE models, the vibration response of the domes is measured on site and systematically compared against the numerical model predictions. Linear FE models are developed that are in close agreement with the measured natural frequencies and in visual agreement with the measured mode shapes. Next, these linear models are extended into the non‐linear range by incorporating the Drucker‐Prager damage criterion. Finally, non‐linear FE models are used to assess the performance of these two domes under seismic loadings obtained from the 1940 El Centro Earthquake acceleration records. The predicted displacements, as well as internal tensile stress levels, are used to make inferences about the potential behavior of these two buildings under the selected earthquake load.

Select this Article		Damage Detection of Bridges by Using Displacement Data of Two Symmetrical Points Yi‐Lin Wang, Xi‐La Liu, FIStructE, FIABSE, FICE, and Cong‐Qi Fang Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000240 Posted ahead of print 15 April 2011 Full Text: \| Download PDF
	+ -	Show Abstract This paper investigates new damage detection method for bridges to ensure their safety. The idea of using displacement data of two symmetrical points for multiple damage detection is presented for the first time. After introducing the concept of Equivalent Element, a novel index termed as ‘Symmetrical Displacement Difference Index, SDDI’ is proposed. The displacement under static load is used for constructing the new index. Then the relationship between the local flexural stiffness change caused by damage and SDDI value is generated. In application, SDDI values can be plotted after the measurement of displacement. The relative changes between the intact state and the damage state in the curve shapes can be used to indicate the position of damage. This new damage detection method based on SDDI is flexible enough to be applied to real‐world bridges with inherent random uncertainty and actual support condition. Numerical and experimental examples have been conducted to examine the suitability of the method. This paper provides a simple, convenient, cost‐effective, and nondestructive damage detection method for bridges.

Select this Article		Shear Testing of Precast Bridge Deck Panel Transverse Connections Scott D. Porter, J. Logan Julander, Marvin W. Halling, F. ASCE, and Paul J. Barr, M. ASCE Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000238 Posted ahead of print 31 March 2011 Full Text: \| Download PDF
	+ -	Show Abstract Precast deck panels are increasingly being utilized to reduce construction times as part of a push for accelerated bridge construction by some state Departments of Transportation. Despite the short‐term benefits, the connections between panels have a history of serviceability problems. To evaluate the service and ultimate behavior of current and newly proposed connections, twelve push‐off tests were performed on precast bridge deck transverse connections for shear. These tests utilized an improved shear specimen geometry that allowed the connection to deform in more realistic shear. This new test setup included spaces that allowed diagonal cracks to form and reinforcement to pull out of the connection. The push‐off tests established the cracking and ultimate shear strengths of each connection detail. These details included a welded connection, an unreinforced grouted connection, and a post tensioned type connection tested with and without an applied compression force. Results of each detail type are compared. The test results show that the post tensioned connection outperformed the other connection details with 2.1 times the shear capacity of a welded connection spaced at 45.7 cm (18 inches).

Select this Article		A Study on the Pavement Swelling and Heaving at State Highway 6 Dar Hao Chen, Tom Scullion, Feng Hong, and Jeffrey Lee Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000237 Posted ahead of print 26 March 2011 Full Text: \| Download PDF
	+ -	Show Abstract A stretch of State Highway (SH) 6 in Texas has been experiencing poor ride quality problems due to continuous pavement swelling and heaving. Because of this, the Texas Department of Transportation (TxDOT) Waco District annually spent hundreds of thousands of dollars to overlay the pavement to keep it smooth. This study is motivated to identify the root causes and solutions to the critical problem. During the forensic study, a systematic approach is employed, which includes non‐destructive and destructive tests. Based on the overall test results, it is revealed that the problem was initiated within the lower portion of the pavement structure (i.e. subgrade) rather than in the upper pavement structure (i.e. asphalt concrete and flexible base). It is further found that the major factors contributing to the subgrade problem include 1) swelling soils, 2) water penetrating into the expansive clay soils, 3) high organics content in the soil, 4) loss of strength of the lime stabilized layer; and 5) high levels of sulfates in the soils. Performance surveys of various potential treatments for remediating the problem associated with swelling subgrade soil and increased moisture were conducted. These performance histories provide input and guidance for the selection of the pavement rehabilitation strategies. Based on the past performance histories, a variety of short‐term and long‐term strategies were recommended to the Waco District office for solving the problem.

Select this Article		Identifying Bridge Rehabilitation Needs Using an Analytical Method Developed for Interpretation of Visual Inspection Data Özgür Avşar, Ward Nicholas Marianos, Jr., M. ASCE, P.E., and Alp Caner, M. ASCE, P.E. Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000233 Posted ahead of print 14 March 2011 Full Text: \| Download PDF
	+ -	Show Abstract Bridge management systems generally rely on the accurate interpretation of findings determined from planned bridge inspections. Bridge inspections typically focus on overall condition of bridge as well as condition of its components. During a recent bridge inspection with a multi‐national team, it was observed that the overall grade of a bridge could be significantly high, even though it contains one or more failing sub‐components. Over the years, it has been observed that failure of a deteriorated component could result in catastrophic failure of bridges. The focus of this paper is to develop an analytical method to interpret the bridge inspection data in such a way that failing components can be identified with a reasonable accuracy for a bridge with a good inspection grade in general. The proposed mathematical model can be utilized in bridge management systems and in maintenance programs of bridge owners to identify immediate rehabilitation needs.

Select this Article		Corrosion Damage Diagnosis of a 44‐Year Old Ammonium Nitrate Prill Tower in a Petrochemical Complex Milad Hallaji, Mohammad Shekarchi, Farhad Pargar, Seyyed Rahman Taheri, and Farnam Ghassemzadeh Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000232 Posted ahead of print 14 March 2011 Full Text: \| Download PDF
	+ -	Show Abstract One of the most aggressive environments for concrete is in an industrial area such as a petrochemical complex compound. In this area, exposure to high corrosive materials such as ammonium nitrate, high carbonation rate (due to the increased concentration of CO₂ in industrial environments) and environmental conditions (relative humidity and temperature fluctuations) can contribute altogether to defect concrete durability. This paper presents a study of corrosion damage of both concrete and embedded reinforcing steel of a 44‐year old nitrate prill tower of a petrochemical complex located in Shiraz, a city in south of Iran. After a thorough visual inspection and observing different deterioration mechanisms, a comprehensive set of conventional experiments in assessing durability of reinforced concrete was carried out. Different degrees of deterioration associated with various exposure conditions along the tower were observed. Results indicated that concrete has been severely decalcified up to 3 cm from its surface. However, reinforcement corrosion was negligible. Moreover, results show that the main reason for the high deterioration of the concrete of the tower was ammonium nitrate solutions.

Select this Article		Performance of an Over‐Excavated Metro Station and Facilities Nearby Yong Tan and Bin Wei Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000231 Posted ahead of print 14 March 2011 Full Text: \| Download PDF
	+ -	Show Abstract This paper examines the performance of an over‐excavated metro station in soft clay within Shanghai metropolitan area, where there are many high‐rise buildings and buried utility pipelines in the proximity. The excavation was supported by stiff concrete diaphragm walls braced by steel pipes. The measured performance included deflections of diaphragm walls, ground settlements, and settlements of the adjacent buildings and utility pipelines. On the basis of daily‐monitored data, the effects of over‐excavation on wall deflections, deflection rates, and the locations where the maximum wall deflections and the maximum wall deflection rates occurred, were investigated. For those buildings in the proximity, the heavy high‐rise steel‐reinforced concrete buildings supported by deep foundations experienced limited uniform settlements while the light brick buildings resting on shallow foundations experienced substantial total and differential settlements. For the adjacent utility pipelines, the excavation‐induced settlements were relatively uniform.

Select this Article		Portuguese Irrigation Canals: Lining Solutions, Anomalies and Rehabilitation Filipe Morgado, J. Grandão Lopes, J. de Brito, and J. Feiteira Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000230 Posted ahead of print 12 March 2011 Full Text: \| Download PDF
	+ -	Show Abstract Irrigation canals are primary hydraulic infrastructures from an agricultural point of view and their performance is highly dependent on the efficiency and durability of their coatings. This paper presents the main conclusions of a survey undertaken in Portugal which concluded that in most situations the following technologies are used: concrete cast on site; precast concrete slabs; prefabricated membranes (polymer bitumen or synthetic). These linings may manifest various pathologies with significant consequences on the amount of water lost due to lack of watertightness. These defects are classified by lining solution and their main causes identified. Finally, an exhaustive set of recommendations and rehabilitation techniques are described in order to minimize water leakage from the canals.

Select this Article		The Murrah Building Collapse: A Reassessment of the Transfer Girder Michael Byfield, BEng, Ph.D., CEng, MICE, MIStructE and Sakthivel Paramasivam BEng, Ph.D., MSc Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000227 Posted ahead of print 12 March 2011 Full Text: \| Download PDF
	+ -	Show Abstract The bombing of the Alfred P. Murrah Federal Building caused a progressive collapse that consumed nearly one half of the building, killing 168 people. The use of a transfer girder along the front face of the building is often cited as the prime reason for the severity of the incident, although this paper provides evidence that suggests the transfer girder may not have been responsible. A method of predicting column failures due to blast is introduced and used to accurately predict the column failure pattern observed during the forensic investigation. The frame was adjusted with the transfer girder replaced with a conventional beam column arrangement. The failure pattern of the reconfigured building indicates that the extent of the collapse would be largely unchanged. This finding has important implications for the design of buildings that may be subjected to accidental or malicious damage. It is argued that the other buildings have demonstrated an ability to survive similar incidents and that the Murrah Building was vulnerable because it combined a glazed façade with open plan architecture, in addition to lacking alternative load paths capable of redistributing loads after multiple column failures.

Select this Article		Influence of Building Type on Post‐Handover Defects in Housing Nuria Forcada, Marcel Macarulla, Alba Fuertes, Miquel Casals, Marta Gangolells, and Xavier Roca Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000225 Posted ahead of print 7 March 2011 Full Text: \| Download PDF
	+ -	Show Abstract Clients’ lack of involvement in defining quality requirements for dwellings built by developers leads to a perception of poor quality at the time of purchase. The research presented in this paper aims to broaden previous research on defects by analysing the defects that remain in the post‐handover stage, which usually lasts 12 months after the handover period, and identifying the factors that influence the appearance of these defects, determining whether a significant difference exists in the quality of the two main residential building types built by developers: flats and detached houses. It also analyses and discusses the areas and elements in which the defects were detected. The data were obtained from client complaint forms completed following the handover of 95 dwellings in Spain. The data were then statistically analysed using a t‐test analysis, a Pearson's parametric correlation and a chi‐square test. The research reveals that clients detect more defects in flats than in detached houses. The lower quality of the materials used in flats and the tighter schedule to which flats are subject may cause these differences.

Select this Article		Numerical Investigation of the Scouring Effect on the Lateral Response of Piles in Sand Sheng‐Huoo Ni, Yan‐Hong Huang, and Kuo‐Feng Lo Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000224 Posted ahead of print 7 March 2011 Full Text: \| Download PDF
	+ -	Show Abstract Scouring around a bridge foundation is a problem of much concern to civil engineers. The main purpose of this paper is to gain a more understanding of the effect of the scouring around the pile on the lateral capacity of the piles embedded in sandy soil. Factors such as soil stiffness, pile head fixity, and pile slenderness ratio (L/B) were studied to show their effects on the variation of the percentage decrease of lateral load capacity (PDC) due to scouring near an isolated pile. The results indicate that the PDC value reaches almost 50% when the scour depth reaches 1.3 to 2.4 times of the pile diameter, and that piles with a fixed‐head are more capable of resisting lateral load loss. Furthermore, the PDC values remain almost constant after the pile slenderness ratio is greater than 10. Hence, the decrease in lateral load due to scouring of the soil will be more serious for short piles.

Select this Article		Snow‐Induced Building Failures Jamie Geis, Kristen Strobel, and Abbie Liel Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000222 Posted ahead of print 7 March 2011 Full Text: \| Download PDF
	+ -	Show Abstract This study examines 1,029 snow‐induced building failure incidents in the United States between 1989 and 2009 and 91 international incidents between 1979 and 2009. Incidents were identified through newspaper archives, including 1,345 articles from 883 unique sources. Most U.S. incidents occurred in New York, New Hampshire, and Massachusetts. Findings show that 37% of all buildings experiencing snow‐induced failure incidents in the U.S. were of metal/steel construction and another 37% were of timber, while 53% of international incidents were metal/steel and 17% were concrete. Warehouses, factories, and commercial buildings were the most common buildings affected. Failures were attributed to the amount of snow, rain‐on‐snow mixes, and building problems. Monetary impacts included building damages ranging between $1,000 and $200 million and business interruption associated with an average building closure of four months. Nineteen fatalities and 146 injuries were reported for the U.S., while 293 fatalities and 586 injuries were reported internationally. These findings describe building failure trends which may be significant, considering potential impacts of accelerating global climate change on the patterns of snowfall frequency and density.

Select this Article		Effects of Instantaneous Live Load on the Performance of Constructed Concrete Members in Cold Regions Mozahid Hossain and Yail J. Kim Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000221 Posted ahead of print 7 March 2011 Full Text: \| Download PDF
	+ -	Show Abstract This paper presents the effects of instantaneous live load on the performance of partially‐cracked axial concrete members (representing on‐site damage) subjected to cold regions environments. A total of 5,289 constructed bridges in the state of North Dakota have been analyzed to identify critical attributes. The simulated environments consist of 100 cycles of freezing‐submerging‐drying cycles at a freezing temperature of −30°C. The instantaneous live load effects are 20%, 40%, and 60% of the concrete compression strength at 28 days. A combined experimental and numerical investigation is conducted to examine the behavior of conditioned concrete cylinders. The research reports that the environmental effects are critical on the performance of existing concrete members in cold regions and the presence of live load accelerates the deterioration of concrete. Internal damage due to the load cycling affects the axial stiffness and crack propagation of the conditioned concrete. All cylinders show volumetric contraction until failure occurs, followed by abrupt dilatation at failure. The live load effects influence the strain energy density and ductility of the concrete. A regression line to predict the strength degradation of the conditioned concrete is compared with numerical models.

Select this Article		New Approach to Modeling Material‐Related Problems Contributing to Project Delays Using Rotational Fuzzy Set H. M. Al‐Humaidi and F. Hadipriono. Tan Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000220 Posted ahead of print 7 March 2011 Full Text: \| Download PDF
	+ -	Show Abstract Construction projects often suffer from material unavailability, which results in failure to meet set schedules. Subjective judgment is commonly used to describe the level of material availability for such projects. Construction experts often state their opinions using linguistic expressions that describe the likelihood of project delay. Fuzzy logic can be used to describe the relationship between material availability and the likelihood of project delay. This paper applies fuzzy modus ponens deduction (MPD) techniques to model material availability and related project delay by incorporating Baldwin's rotational fuzzy‐set models. This deduction technique consists of three processes: the Truth Functional Modification (TFM), Inverse Truth Functional Modification (ITFM), and Lukasiewicz Implication Rule (LIR). The TFM finds the truth of a fuzzy set, the ITFM is the inverse of TFM, and the LIR obtains the truth of an implication relation. This study presents a model that can be used to simulate material availability level and its impact on project schedule. Validation of the model showed between good and very good overall appearance and suggests that the model is applicable to the construction industry.

Select this Article		Evaluation of the Lateral Load‐Resisting System of a Stadium Structure J. Gustavo Tumialan, M. ASCE, Stan W. Zagajeski, M. ASCE, Nestore Galati, M. ASCE, and Matthew R. Sherman, M. ASCE Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000217 Posted ahead of print 18 February 2011 Full Text: \| Download PDF
	+ -	Show Abstract This paper describes an evaluation of the lateral load‐resisting system of an existing monolithic, cast‐in‐place, reinforced concrete (R/C) stadium structure completed in the early 1930's. A major renovation/expansion of the stadium completed in the 1990's included modifications of some of the original exterior infill masonry wall, including removal of masonry and enlargement of existing openings. A preliminary study raised concerns about the impact of these modifications on the lateral load‐resistance of the stadium structure. A new study, which consisted of an evaluation of the structure's performance using in‐situ lateral load‐testing of the structure, numerical analyses, and monitoring of the actual stadium‐sway movements during football games, was undertaken in 2006 to determine the adequacy of the lateral load‐resisting system of the stadium. The results of this study, which are reported in this paper, demonstrate that the masonry modifications made during the renovations/expansion of the stadium did not impair the structure's resistance to code‐prescribed lateral loads and that no major structural repairs were required.

Select this Article		Optimizing Inspection Policies for Buried Municipal Pipe Infrastructure Hesham Osman, Ahmed Atef, and Osama Moselhi Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000216 Posted ahead of print 18 February 2011 Full Text: \| Download PDF
	+ -	Show Abstract Condition assessment is an integral component in any infrastructure asset management system. Without condition information, asset managers lack the ability to make appropriate decisions regarding needed maintenance, rehabilitation and replacement of infrastructure. Existing and emerging technologies for the condition assessment of water and sewer pipes provide a better picture of the state of these buried assets. Unfortunately, many of these technologies are costly and provide results that are not always highly reliable. This paper presents a methodology for optimized condition assessment policies to assist asset managers in balancing the value of information revealed by a condition assessment technology with the cost of obtaining this information. The paper describes the computational platform of the developed methodology and focuses primarily on the optimization process which utilizes Partially Observable Markov Decision Process (POMDP) and genetic algorithms. These policies determine the most appropriate condition assessment technology and interval between inspections. The developed methodology takes into consideration direct and indirect costs of infrastructure failure. Optimization models are developed at both the asset and network levels. A case example of the water distribution network for the City of Hamilton, Canada, is presented to demonstrate the use and capabilities of the developed methodology. At the asset level, results allow the asset manager to select the most suitable condition assessment technology and inspection interval for a particular pipe. At the network level, results enable the proper allocation of a condition assessment budget across all pipes in the system.

Select this Article		Computational Modeling of Fatigue Performance of an Integrated Crosstie System for Advanced Rapid Transit Yail J. Kim, Colin MacDougall, T. Ivan Campbell, and Mark F. Green Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000215 Posted ahead of print 11 February 2011 Full Text: \| Download PDF
	+ -	Show Abstract This paper presents the fatigue behavior of an integrated crosstie system for an Advanced Rapid Transit (ART). The crosstie system consists of steel base plates welded to a hollow structural section, and a concrete guideway slab. The steel‐wheeled ART is operated by linear induction motors (LIM) and provides a unique load configuration to the crosstie system, including electromagnetic force and gravity load. To absorb dynamic effects from the ART, elastomeric pads are placed under the base plates. A 3‐dimensional finite element analysis is conducted to examine the fatigue performance of the crosstie, based on cumulative damage theory. The study focuses on stress progression, displacements, and stress concentrations in the crosstie system subjected to fatigue load of up to 3 million cycles. The effect of pad deterioration on the fatigue behavior of the crosstie is evaluated. Design recommendations to improve the sustainability of the crosstie system are discussed.

Select this Article		Building Commissioning: What Can Denmark Learn from the US Experience? Rúnar Örn Ágústsson and Per Anker Jensen Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000214 Posted ahead of print 11 February 2011 Full Text: \| Download PDF
	+ -	Show Abstract Building commissioning has been gaining momentum and awareness within the building industry as a comprehensive quality assurance process that can be used throughout the buildings life cycle to ensure that the needs and requirements the owner has for the building are met. Although building commissioning is gaining momentum it is still far away from being viewed as normal practice within the building industry. Of the countries that are the closest to succeeding in making building commissioning normal practice, USA is the clear leader. In countries were commissioning is taking its first steps or has not yet been used it would be wise to try to learn from the leading nations, how they have implemented commissioning to decrease the time it will take for commissioning to become normal practice. Since the USA is among the leading nations in implementing commissioning, there is a lot that can be learned from how that process has evolved and all the effort that has been put into research on building commissioning. This article investigates how the commissioning process is undertaken at a leading commissioning providing consulting company in Denmark and presents a case study with a comparison between two shopping malls out of which one has not been through a commissioning process, while the other has. The benefits of commissioning are outlined and proposals for how the process can be improved in the Danish consulting company compared to the well established ASHRAE 0‐2005 guideline. Finally the article discuss and concludes what the future steps for commissioning in a country like Denmark should be based on how commissioning has evolved in the US.

Select this Article		Impact of 2008 Hurricane Ike on Bridge Infrastructure in the Houston/Galveston Region Matthew Stearns and Jamie E. Padgett Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000213 Posted ahead of print 11 February 2011 Full Text: \| Download PDF
	+ -	Show Abstract The storm surge, wind and waves produced by Hurricane Ike in 2008 caused notable damage to the transportation infrastructure in the Houston/Galveston region of Texas. This paper presents the lessons learned from damage to bridge infrastructure in the Houston/Galveston region observed after Hurricane Ike, with comparisons to empirical evidence from past hurricane events on common failure modes and design details affecting bridge performance under hurricane induced loads. A rich set of damage data is developed drawing upon post event inspections and reconnaissance data to present details such as bridge type, failure mode, and surge elevation for the 53 damaged bridges. Many of the damaged structures in the region were either constructed of timber or were low‐clearance water‐crossing bridges, and these bridges were often completely destroyed by the storm surge and wave loading. Scour and debris also hampered the performance of both major structures and rural bridges. The evidence from the performance of these structures highlights the need for new design alternatives or retrofits such as the use of shear keys and restrainer cables, grated decks, or replacement of timber bridges with box‐culvert structures, among other solutions.

Select this Article		The Integral Lifting Project of the Qifeng Bridge : Case Study Y. Zhao, J. F. Wang, and M. Pang Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000211 Posted ahead of print 11 February 2011 Full Text: \| Download PDF
	+ -	Show Abstract To fulfill the navigation development plan of the Hu‐Jia‐Shen Channel located in the eastern coast of China, it is necessary to upgrade its width and clearance height. Qifeng Bridge, an arch bridge over the channel, is required to be raised by 2.5m using the integral lifting method. In this paper, the operation principles of the hydraulic jack system, the composition of the supporting structures as well as the lifting process of the bridge are presented. To verify the proposed procedures adopted in this project, a 3D finite element method (FEM) model, incorporating bridge capping beam of main span and supporting girder, is established to analyze its contact behavior and also the stress distribution characteristics. The induced stresses in the superstructure and supporting structures are also monitored and analyzed.

Select this Article		Utilization of Existing Blast Analysis Software Packages for the Back‐Calculation of Blast Loads Andrew Sorensen, Ph.D. and William L. McGill, Ph.D., P.E. Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000209 Posted ahead of print 22 January 2011 Full Text: \| Download PDF
	+ -	Show Abstract Recent increases in the number of terrorist bombings and explosions have led to increased need for post‐blast investigators. Numerous advances have been made in the area of chemical analysis of explosive residues, but little work has been done to aid post‐blast investigators in the determination of explosive charge weight using post blast structural damage. This technical note discusses the results of a review of existing blast analysis software packages for their ability to be used as a forensic tool supporting post‐blast investigations. The recurring limitations of the software found in this review are discussed. It is determined that individually the software packages do not show much promise as such a tool, but that when used concurrently, they may have some value to the post‐blast investigator. However limited knowledge about the built in safety factors as well as the ability to specify and modify boundary conditions in the software packages have left the authors to pursue other avenues.

Select this Article		Bridge Clearance Evaluation Based on Terrestrial LiDAR Scan Wanqiu Liu, Shen‐En Chen, and Edd Hasuer Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000208 Posted ahead of print 20 January 2011 Full Text: \| Download PDF
	+ -	Show Abstract Low vertical clearance bridges, over roadway, are vulnerable to over‐height vehicle collision damages. Collisions can cause driver and passenger injury/fatality, property loss of vehicle and bridge owners, and can severely jeopardize the bridge structural capacity. However, accurate measurements of bridge vertical clearance can be difficult, especially when height differentials occur either due to site topography or due to super‐elevated bridge deck. An automated measurement technique using LiDAR scan is introduced to provide high‐precision clearance data for bridge surfaces, from which minimum vertical clearance location can be easily identified. Traffic can induce noises in terrestrial LiDAR imaging, hence, approach to reduce noise is proposed. The results from field measurements on four bridges in Mecklenburg County, North Carolina, demonstrated the value of LiDAR‐based measurement techniques and confirmed the deviation measurements from design criteria, which can be associated to the collision damages due to deficient clearances.

Select this Article		Study of the Common Pathologies in Composite Adobe and Reinforced Concrete Constructions Alice Costa Ruano, Aníbal Guimarães da Costa, and Humberto Varum Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000200 Posted ahead of print 30 December 2010 Full Text: \| Download PDF
	+ -	Show Abstract Adobe construction is an important part of the built heritage in the Central Region of Portugal. The protection and rehabilitation of buildings of this type is becoming of increasing interest. In‐depth knowledge will enable the preservation and assessment of this ancient technique with a high potential for sustainable construction, which forms the core aspect of the current research. The rehabilitation of these structures depends on an adequate diagnosis of their pathologies. Those most frequently observed are related to structural problems, absence of structural cohesion, damage by the wooden covering structure, and the effects of damage by water effect in to the structure and walls. These are often associated with a lack of maintenance of the buildings over a long period of time, or with design detailing problems, namely stemming from when reinforced concrete was introduced into the traditional adobe construction system, or again by external environmental factors. Knowledge of the process of the introduction of reinforced concrete and its motifs are also important to this study. The pathologies observed in the mixed adobe/concrete system in addition to the traditional system are related to basement moisture, corrosion of reinforced concrete, wall cracking, degradation in coverings and single parts of the curtain wall/façade and design errors. A timely correction of pathologies will mean a significant reduction in the cost of repair works, or even in saving the construction from ruin. Minimum maintenance rules applied to old buildings, associated to a proper understanding of its behavior, can increase the longevity of this vast heritage. On top of this, by protecting the identity of our towns, apart from the benefit of heritage and cultural preservation, it also encourages tourism and consequently increases local development.

Select this Article		Capacity Evaluation of a Severely Distressed and Deteriorated 50‐Year Old Box‐Beam with Limited Data Upul Attanayake, P.E., M. ASCE and Haluk Aktan, P.E., M. ASCE Journal of Performance of Constructed Facilities doi:http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000142 Posted ahead of print 25 August 2010 Full Text: \| Download PDF
	+ -	Show Abstract In 2005, randomly selected 15 adjacent box‐beam bridges were inspected to document their performance with consideration to the evolving design procedures. Longitudinal cracking along the soffit of several fascia beams was documented. After evaluating inspection data, bridge engineer recommended the replacement of a severely distressed fascia beam from the Hawkins Road Bridge in Jackson County, Michigan. The beam was salvaged and the capacity was evaluated through load testing. Remaining prestress was 75% of the initial prestress that is 5% less than the final prestress used for the design. Concrete modulus of elasticity was evaluated as 35.4 GPa and the nominal compressive strength as 54.4 MPa. Analysis of load test data indicated that a bridge with the beam in this distressed state is safe to operate. This is assuming the transverse connectivity between the beams is sufficient for load distribution as envisioned in the design. The importance of identifying concealed corrosion, and quantifying material properties and load distribution is highlighted.