Journal of Performance of Constructed Facilities

Forum papers are thought-provoking opinion pieces or essays founded in fact, sometimes containing speculation, on a civil engineering topic of general interest and relevance to the readership of the journal. The views expressed in this Forum article do not necessarily reflect the views of ASCE or the Editorial Board of the journal.

In the past decades, several guidelines have been developed for designs against progressive collapse based on a number of experimental and numerical studies that have been conducted. However, the majority of the previous experimental and numerical investigations focused on the response of buildings under the scenarios of loss of interior or exterior columns. However, the loss of a corner column in the event of a terrorist attack is more likely to trigger progressive collapse given the paucity of surrounding elements that could help to redistribute the axial force initially resisted by the lost corner column. In order to investigate the progressive collapse of RC frames under the loss of a corner column scenario, an analytical model was proposed and subsequently validated through comparison with the experimental results. The influences of the beam longitudinal reinforcement ratio, beam depth, beam width, column width, and joint transverse reinforcement ratio on the progressive collapse performance of RC frames were also parametrically studied via the validated analytical model.

Observations after the 2011 Van-Erciş earthquake show that some of the recently constructed reinforced-concrete buildings were either heavily damaged or had collapsed. As a building subtype, wide-beam, infill-joist block reinforced-concrete frames got attention because of their mode of failure. There were several such buildings that failed in strong-column, weak-beam mode. Considering the demand created by the earthquake, structures were not expected to reach their full capacity. The purpose of this study is to review the history and current practice of infill-joist frames in Turkey and to conduct a performance evaluation of infill-joist frames designed per the current earthquake code (2007). Regulations for this building subtype are critically reviewed, and the designer’s response to code regulations is discussed. Results indicate that the force-based design approach used in the current code is not always adequate to satisfy the displacement demands. In addition, it is observed that layout, proportioning, and detailing requirements of beam-end regions and beam-column connections do not always warrant ductile behavior as targeted.

A new nonlinear static alternate path analysis technique coined pulldown analysis is presented as an easy-to-implement alternative to the existing pushdown analysis for assessing the load redistribution capability of a building after a critical structural element has been suddenly removed. Unlike the pushdown analysis where gravity loads within the affected bays of a building are directly amplified, the pulldown analysis is associated with a downward force that is statically applied at the removed element location. This static pulldown force is equal in value to the axial compression force in the to-be-removed column of the intact frame multiplied by a dynamic increase factor (DIF), which aims to generate the best match of the peak dynamic responses of a damaged building through a nonlinear static analysis. A seismically designed nine-story steel moment frame is used as an example to illustrate the pulldown analysis procedure. Results from progressive collapse assessment of the example frame using the pulldown analysis and pushdown analysis are critically compared. It is found that the pulldown analysis is able to estimate the peak dynamic responses of the example frame with at least the same level of accuracy as those predicted by the pushdown analysis. Moreover, the pulldown analysis may lead to improved prediction of some important structural responses such as the peak axial forces in columns next to the removed column. Finally, to demonstrate how empirical DIF formulas for the pulldown analysis can be derived for practical applications, curve-fitting of data points, each consisting of the DIF and a parameter that approximately reflects the residual capacity level of the damaged frame under a given column removal scenario, is carried out for the example frame.

In 2008, 77 prestressed concrete adjacent box girder (PCABG) bridges were selected and inspected to determine their typical defects and document their performance. Longitudinal cracking in the web of many beams was documented as the main defect. To evaluate the influence of longitudinal cracking on capacity of the PCABG, two adjacent box girders were compared that were made with the same procedure. One box girder (beam No. 1) had no defects, whereas the other (beam No. 2) had longitudinal cracks in the web. The results show that the longitudinal cracks in the web of beam No. 2 changed the trend of the expansion of the cracks by connecting the vertical cracks close to the longitudinal ones and shortening the range of the vertical cracks covered and the length of the plastic hinges. Furthermore, the longitudinal cracks made the curvature of beam No. 1 less than that of beam No. 2 and made the compression strain of each side different. However, the existence of longitudinal cracks had little effect on the cracking moment and the ultimate flexural bearing capacity. The residual prestressing forces indicated that an approximately 23% prestressed force was lost for both beams.

Numerous studies have indicated that the practice of ignoring the contribution of reinforced concrete (RC) slab in resisting progressive collapse is overconservative; however, the extent of influence of a slab, especially in terms of dynamic responses, have been rarely studied. To quantify this effect, two series of RC beam–column substructures (named DS and DF in this paper), with and without slab respectively were subjected to a series of dynamic tests involving the sudden removal of a corner support. To further elucidate the dynamic response of RC frames against progressive collapse, the experimental data acquired in this study were compared with their respective static responses derived in a previous series of tests published in another paper. The dynamic effects were evaluated by the newly defined term dynamic load increase factor (DLIF), which was defined as the ratio of static ultimate strength (SUS) to dynamic ultimate strength (DUS). The SUS of the test specimens had been captured in their respective static tests; however, the DUS of each specimen could not be determined based on a single dynamic test. Thus, a single-degree-freedom (SDOF) model was validated and used to conduct incremental dynamic analyses for each specimen.

This paper presents the results of a test program whose goal was to better understand the contribution of individual elements to the performance of typical light-frame wood structures during tsunami loading. The intent was to be able to replicate failures in a structural engineering laboratory that were observed during laboratory experiments of hydraulic loading on wood walls at the NEES Tsunami Facility at Oregon State University. The elastic and inelastic response of shear walls, out-of-plane walls, and a full light-frame wood structural system subjected to varying lateral loads were observed using digital image correlation (DIC). The DIC provided a noncontact, three-dimensional measurement system that returned displacement results measured at multiple areas of interest on the wall surface. Overall, these experiments show that the elastic stiffness and ultimate capacity of the shear wall is significantly higher at full height than intermediate heights on the wall, and the ultimate lateral capacity was higher than a full structural system. The results indicate that the out-of-plane wall behaves like a one-way slab with limited contribution from adjacent studs in carrying load. The stud to bottom plate connection failures observed during the wave tank tests were successfully reproduced and indicate that the nailed connection needs to be reinforced to utilize the available capacity of the individual framing members.

This paper stems from research in the University of Alabama’s Department of Civil, Construction, and Environmental Engineering. Engineering design failures fall into two broad categories, those that occur because of a hitherto unknown or unprecedented technical cause, and those that occur because of a known cause that was overlooked during the design process. The latter can be considered a failure of design management, and the purpose of this paper is to compare and contrast inadequate design management to unprecedented technical issues as a cause for engineering failures. Failures that occur to improper maintenance or abuse are not the scope of this paper. Two approaches were taken, namely: (1) evaluation of current and historical engineering failures for instances of inadequate design management and/or unprecedented technical issues; and (2) review of filed claims data for design errors and omissions to determine whether inadequate design management is a substantial issue. This research may provide useful information in understanding how both categories limit the success of the design process.

Despite the importance of the condition assessment (CA) stage in the asset management process, literature review reveals that there are some drawbacks in the current practices. The objective of this paper is to develop a condition assessment model for buildings. A new building asset hierarchy is proposed in which the space is the principle element of evaluation. Physical components within a space are categorized into four main categories. Data are collected from experts via questionnaires to assign relative weights to models’ attributes using both the analytical network process (ANP) and the analytical hierarchy process (AHP) techniques. Finally, the multi attribute utility theory (MAUT) is used to calculate the physical condition assessment of spaces and the entire building. The developed model is applied to a case study of an educational building located in Montreal. Results of the model are compared with the calculated results by the building facility management team. Many lessons are learned from the study; among the most significant findings is the importance of building categories and subcategories that differ according to space type. This model will assist owners and facility managers in the condition assessment phase during the asset management process by applying several tools and techniques to provide an accurate condition assessment.

Turkey is located in one of the most seismically active regions in the world. In the 1999 Marmara earthquake in Turkey, more than 20,000 people died. On October 23, 2011, an earthquake with a magnitude of 7.2 on the Richter scale struck the Van and Ercis cities, causing more than 600 casualties. The epicenter was located in Zone 1 in the earthquake zones map of Turkey. In this paper, the results of a field reconnaissance survey of the affected earthquake area were reported and common structural failures in reinforced concrete (RC) structures were summarized. The observed failure modes included weak column–strong beam formations, hinging in the columns, column–beam joint failures, lap splice inadequacies, poor concrete quality, insufficient transverse reinforcement, buckling of longitudinal column reinforcement, pancake type of collapse mechanism, soft- and weak-story failures, and short column formations. The buildings in Van and Ercis have also several undesired architectural features, such as the presence of mezzanine floors and penthouses, commercial use of ground floors, etc.

Based on a wind-vehicle-bridge analysis system and quasi-steady pneumatic force coefficient data obtained from wind tunnel tests, the problem of moving vehicles on a cable-stayed bridge deck overturning in a strong wind environment is studied, with the probability evaluation as the emphasis. It is put forward that the evaluation of a vehicle’s overturning is a probability problem that a stochastic process overpasses a threshold level, and the influence of the statistic process characteristics of excitations on driving safety is profoundly discussed in the paper. The analysis shows that the higher the driving speed, the more obvious the effect of statistic process characteristics tends to be. Moreover, the influence degree of stochastic process characteristics is relevant to the wind velocity range of the dynamic reliability curve and the range of the probability distribution for the mean wind velocity. When the range of the former is broad enough and overlaps with the range of the latter, the influence of stochastic process characteristics should be considered. Wind barriers can promote a safe driving velocity from 80 to $100\mathrm{km}/\mathrm{h}$ under normal weather conditions. Under extreme weather conditions, traffic control measures should be implemented to maintain the bridge’s traffic service. Wind barriers together with the speed limitation ($80\mathrm{km}/\mathrm{h}$) can ensure that a truck passes the bridge safely during storm conditions ($24.5\mathrm{m}/\mathrm{s}$, Beaufort Scale 10). When the natural wind is a violent storm ($28.5\mathrm{m}/\mathrm{s}$, Beaufort Scale 11), the speed limitation should be $60\mathrm{km}/\mathrm{h}$.

This study evaluates the feasibility of energy piles equipped with a large-diameter drilled shaft under unfavorable ground conditions. The cast-in-place concrete energy pile was constructed at a test bed in dredged and reclaimed ground in which a confined aquifer exists. Two different configurations of heat exchange pipes (W-shape and S-shape) were designed on each side of the energy pile to compare their thermal performance. The drilled shaft reaches to a depth of 60 m whereas the heat exchange pipes are inserted to about 30 m below the ground surface. In a comparison of constructability, the S-shape heat exchanger resulted in faster installation by about 50% over the W-shape, which implies that the S-shape pipe may provide better constructability for the given construction conditions. A series of in situ thermal response tests (TRTs) were performed to compare the thermal performance of each heat exchanger. The relative heat exchange efficiency (eff) of the W-shape and the S-shape heat exchangers were determined to be 19.15 and 18.88, respectively, which means that the two different types of heat exchange pipe configurations practically yield similar thermal performance. One of the TRTs conducted in the test bed was simulated by a computational fluid dynamics (CFD) numerical model to verify the feasibility of adopting TRTs for energy piles, which reproduces quite well the TRT experimental results.

Although aftershocks have the potential to cause severe damage to buildings and threaten life safety, their effect in seismic risk analysis is not explicitly accounted for in modern building design codes, nor in emerging methodologies such as performance-based seismic design. The ultimate objective of this study is to systematically integrate aftershock hazard into performance-based earthquake engineering (PBEE) through analytical studies with structural degradation models derived from publicly available experimental data. In this paper, the first step is made by introducing a procedure to compute the probability of a mainshock-damaged woodframe building entering different damage states as a result of aftershock. Aftershock fragilities are developed by performing incremental dynamic analysis (IDA) using a sequence of mainshock-aftershock ground motions. To compute the seismic response of the damaged building, IDA is performed using a sequence of mainshocks of different intensity levels combined with random aftershocks. The variation in aftershock fragilities for each of the damage states for several different mainshock intensities is presented. The effect of the mainshock damage is to alter the fragilities and is quantified for the building investigated. It is observed that the fragility curves for collapse risk have a similar shape for the mainshock-aftershock sequences for different levels of mainshock. As well as that there was an unexpected result that, if the building model survives the mainshock, the additional collapse risk because of aftershocks may not be as critical as originally thought for engineered woodframe construction. The effect of aftershocks on damage states appears to be more significant, relatively speaking, than on collapse of low-rise woodframe buildings, indicating that including aftershock hazard on performance-based seismic design will be significant.

This study investigates the field performance of culvert joints in five existing pipe culverts. Test culverts consisted of two corrugated metal culverts, two reinforced concrete culverts, and one high-density polyethylene culvert. Culverts were selected for backfill depths less than 1.5 m and inner diameters ranging from 0.9 to 2.1 m. Static loading was applied to the culverts by parking a heavily loaded truck at different positions above the culvert joint. Dynamic loading was applied by driving the truck over the culvert at speeds ranging from 8 to $48\mathrm{km}/\mathrm{h}$. Culvert deflections and strains were measured near one of the culvert’s joints. Separation at the joint was also measured. The results indicate that separation at the joint was quite significant at times. In the worst case, the measured separation at the joint was equal to 50% of the measured deflection. Strains measured near the joint in steel culverts were significantly smaller than the yield strain. The dynamic deflections were typically 10–40% less than the static deflections.

The Wenchuan earthquake that occurred in China in 2008 caused extensive damage and loss of life and property. Comparison of the vulnerabilities between former and current reinforced concrete (RC) frame structures after the 2008 Wenchuan earthquake was performed in order to minimize of future losses in the paper. A formal representative type of damaged RC frame building in Wenchuan County was studied by nonlinear finite element method (FEM). Probabilistic seismic demand models (PSDM) for RC frame structures was built to assess the safety levels of the former and the current RC frame buildings. The fragility curves for immediate occupancy (IO), significant damage (SD), and collapse prevention (CP) damage levels of the two RC frame buildings were compared and analyzed. The result indicates the safety levels of the current RC frame building are well improved compared to the former RC frame building before the 2008 Wenchuan earthquake in China.

Ten full-size ($3.7\times 4.9\mathrm{m}$) plywood roof diaphragms were constructed using metal-plate-connected (MPC) common and hip wood trusses or joists, typical of single-family dwelling (SFD) construction. The specimens included three gable roof slopes of 33, 67, and 100%, a hip roof of 33% slope, and a flat roof, with a horizontal bottom chord. These roofs were constructed and tested in duplicate to make the total of 10 roofs. Gable and hip roofs were tested with plywood sheathing applied to the eaves, with plywood sheathing removed from the eaves, and with a gypsum ceiling attached to the bottom chord of the trusses. Roofs were tested following standard procedures and analysis. Results showed eave plywood had a negligible effect on diaphragm apparent stiffness; pitch affected gable roof apparent stiffness significantly but did not affect gable roof strength; hip roofs had almost the same apparent stiffness as flat roofs and had the same strength as flat roofs; gable roofs had apparent stiffnesses that were about 50% that of the flat roofs; and gypsum provided more than one-third of the total roof apparent stiffness at slopes of less than 33%. There was no effect of pitch on roof strength in any configuration; all roofs exhibited approximately the same shear strength. Failure modes of roofs included nail withdrawal, nail tear-through, metal plate tear-out on trusses, and chord tensile failure.

This research defines diagnosis criteria in RC one-way slabs with severe corrosion at the lower prestressed reinforcement of the joists and proposes specific actuation criteria and constructive recommendations to increase safety. The corrosion of this reinforcement is the most common damage in building structures, and the use of aluminous cement in the precast joists can aggravate the corrosion. The usual cases of entire residential buildings with different degrees of damage and with a few or all joists affected in a slab have been simulated. American Concrete Institute load test for existing structures is used as an acceptance criterion in the simulations, and a ratio between the ultimate load and the service load is defined as a valuation coefficient. In this way, the residual safety for a damaged structure is known. Results are in accordance with extensive experience in real intervention cases, which often still have high safety reserves.

This paper describes the details of installation and operation of a commercially available wireless system to measure response of interior cosmetic cracks in a residential structure over a period of a year. Wireless data loggers managed the response of low-power-draw potentiometers that measured micrometer changes in crack width. Systems like those studied herein are useful to describe the performance of any component of a constructed facility that involves existing cracks such as bridges, building facades, or other structures. Four wireless nodes were deployed within and around a test home of frame construction to qualify the system for further field use. Considerations for qualification included: fidelity of the measured crack response, ease of installation, resolution of structural health measurement, length of operation under a variety of conditions without intervention, and ease of display and interpretation of data. The article first describes the components of the system and the measurement plan. It then closes with an evaluation of the considerations for field qualification.

Wastewater pipes age and deteriorate over time, and utilities face great challenges in operating and maintaining their wastewater pipe infrastructure. Thus, systematic assessment and evaluation programs are required for efficient monitoring of the conditions and performance of wastewater pipes. This paper presents a rating system for use in evaluating the condition of wastewater pipes that can assist utilities in planning, prioritization, maintenance, and repair/rehabilitation/replacement decisions. A condition-rating system also can be an extremely useful tool in benchmarking pipe conditions, which allows the comparison of pipe segments within the system with each other and with similar segments in other systems. Currently, many utilities use the National Association of Sewer Service Companies’ (NASSCO’s) pipeline assessment and certification program (PACP) or have developed their own, in-house condition-rating system based on PACP. Most of the condition-rating systems currently in use are based on structural and operational defects of pipes. The proposed methodology considers defects identified from inspections, e.g., cracks, holes, and corrosion, and other parameters that affect the conditions and performance of wastewater pipes, such as soil characteristics, loading, and flow velocity. The proposed performance-rating system evaluates each parameter and combines them mathematically through a weighted summation and a fuzzy inference system that reflects the importance of the various factors. The framework provides a noticeable improvement from the conventional practice of using solely inspection data as a means to evaluate the wastewater pipe infrastructure system, because the model accounts for inspection data and other parameters that influence wastewater pipe performance. The fuzzy logic was good for approximate reasoning and incomplete information. The fuzzy inference model was found to have many advantages over the weighted factor model. The fuzzy inference model provided more sensitive results, whereas the weighted factor model provided more static results since the weights assigned to each parameter were fixed and distributed throughout all parameters in the model. In addition, the fuzzy inference model accounted for the combination effect of dependent parameters.

The Roman Bridge of Lugo (Spain) has undergone many restorations throughout the last millennium. It currently supports heavy and constant pressures resulting from traffic loading. Therefore, frequent inspections are required. Within this article, different nondestructive testing (NDT) technologies were combined for the inspection and as-built three-dimensional (3D) documentation of this masonry arch bridge. Both mobile and static light detection and ranging (LiDAR) devices, integrated with digital cameras, were considered to analyze the exterior of the bridge whereas the ground penetrating radar (GPR) equipment was used to characterize its internal stonework. A 3D textured bridge model is given, which is combined with inner details from GPR. Its analysis could certainly benefit masonry arch bridge inspection.

A pulse-shaped split Hopkinson pressure (SHPB) was employed to determine the dynamic compressive mechanical responses of concrete cores. The loading pulses in SHPB experiments were precisely controlled to ensure that the core specimen deforms at a nearly constant strain rate under dynamically equilibrated stress during compression. A modified two-parameter Weibull distribution was used to analyze the test data. The Kolmogorov-Smirnov goodness-of-fit test was used to decide whether test data come from a population with this distribution. On the basis of the test data, Kolmogorov-Smirnov goodness-of-fit test, and probability plot, it is found that the modified Weibull model can be applied to compressive strength for concrete cores. In addition, the strain rate effect on the compressive strength of cores can be accurately predicted from the modified Weibull model.

Diamond grinding (DG) has been used by various districts to improve skid resistance (reduce accidents and fatalities) and improve ride quality [reduce international roughness index (IRI)], with the added benefit of reducing tire/pavement interface noise. The Texas Department of Transportation has used DG on both jointed concrete pavement (JCP) and continuously reinforced concrete pavement (CRCP). This study performed crash accident analysis both before and after DG on a recent project section. After the completion of DG, the occurrences had reduced by approximately 62 and 46% for fatalities and incapacitating injuries, respectively. There was an average IRI reduction of approximately $44\mathrm{in.}$ ($0.70\mathrm{m}/\mathrm{km}$), or 40%, immediately after treatment. This study also analyzed eleven projects to derive a statewide trend on various surface characteristics of pavements due to DG, with the oldest section studied approximately eight years after treatment. Immediately after DG, the average skid number (SN) increased 5.6, or by about 30%. Depending on the existing pavement conditions, the range of the increase in SN varies from 1 to 18. Similarly, there was an average IRI reduction of approximately $0.95\mathrm{m}/\mathrm{km}$ ($\text{60\hspace{0.17em}\hspace{0.17em}}\mathrm{in.}/\mathrm{mi}$) immediately after the DG, or about 40%. Depending on the existing pavement conditions, the range of IRI reduction varies from $0.32–1.94\mathrm{m}/\mathrm{km}$ ($20–122\mathrm{in.}/\mathrm{mi}$), or 17–57%. For deterioration rate under the effect of factors such as time and traffic, each year the SN decreases by approximately 2.0 and IRI increases by approximately $0.03\mathrm{m}/\mathrm{km}$ ($1.7\mathrm{in.}/\mathrm{mi}$).

The curb and gutter inventory of the city and county of Denver was established in 2004. The current round of data collection was initiated in the summer of 2011. The equipment used in previous data collection was good, but some significant problems were uncovered during the collection process. Updated more economical units including a Panasonic Toughbook tablet computer and Arc geographic information system (ArcGIS) program are being utilized in current inspection. By the end of 2012, 2,647 km (1,645 mi) out of 5,311 km (3,300 mi) of curbs and gutters had been inspected. Previously developed simplified condition index (SCI) was employed and calculated for the completed inventory to examine the overall condition of curbs and gutters. By comparing the data in 2004 and 2012 for 8,000 common streets, the overall SCI dropped approximately 3.8 over about a period of eight years. It indicates a deteriorating rate of approximately 0.5 SCI per year.