Journal of Performance of Constructed Facilities

In order to provide a realistic basis for structural damage identification and safety evaluation of long-span bridges, the modal parameters of a kilometer-scale cable-stayed bridge are identified using the wavelet transform (WT) method. Sutong cable-stayed bridge (SCB), which was excited by typhoon Haikui, was taken as the research object. Based on the structural vibration responses recorded by structural health monitoring system (SHMS) of SCB, modal parameters including the frequency and the damping ratio of the bridge were identified using the WT method. Four vertical, two torsional, and one lateral modes were selected for analysis. After comparing the analysis results with those from the related references, the whole-process variation of modal parameters of the SCB during typhoon Haikui was investigated. Furthermore, the relationship between modal parameters and wind speed was analyzed. Results show that the modal parameter identification based on the WT method is stable and reliable. The influence of wind speed on modal frequencies is small. However, its influence on modal damping ratios is remarkable and shows some of regularity. With the increase of wind speed, the first four vertical and first torsional modal damping ratios increase while the first lateral and second torsional modal damping ratios decrease.

Post insulators are key components of most electrical substation equipment, but they are vulnerable during earthquakes. To better understand the seismic response of post insulators, this paper presents an experimental program that involved two types of 230-kV disconnect switches post insulators. Several solid ceramic (porcelain) and hollow-core composite (polymer) insulators were tested. The experiments consisted of static loading and dynamic shaking table tests. The static cyclic-loading, resonance-search, and pull tests—including material characterization—allowed the determination of the insulators lateral stiffness, fundamental frequency, and mode of failure. Moreover, failure loads and corresponding displacements and strains were determined. Additionally, the shaking table tests involved substructured dynamic tests of single porcelain and polymer post insulators. The main objective of the static and dynamic tests was to compare the behavior of porcelain and polymer post insulators under lateral loading. It was found that while the polymer insulators have much lighter mass than the porcelain ones, and in turn are more favorable from a seismic performance perspective; they have a comparable structural response to that of the porcelain insulators.

Over-reinforced sections fail suddenly by compression concrete crushing when their ultimate compressive strain has been exceeded but the longitudinal reinforcement strain has not yielded. This study investigates the use of cementitious repair materials for the compression side of over-reinforced concrete beams to change their failure mode to ductile failure. In this study, 11 over-reinforced concrete beams were cast (1 as a control specimen and 10 as strengthened beams). The study’s strengthening material was an ultra-high-performance strain-hardening cementitious composite (UHP-SHCC). The effect of shear connectors with the strengthening material was investigated. Meanwhile, replacement of the concrete cover, use of a welded wire mesh inside the additional layer, and concrete strength were tested. Crack pattern and failure modes were noted, and deflection behavior, failure loads, steel strains, and crack width were measured. The tests results showed that using strengthening UHP-SHCC material is a highly effective method to increase the load--carrying capacity of existing over-reinforced concrete beams, and demonstrated the contribution of the proposed technique to improving the ductility behavior of over-reinforced concrete beams.

Structural robustness is investigated in this study according to its opposite property, i.e., structural vulnerability, which is calculated as the assembly of component vulnerability measured by the vulnerability coefficient. Different types of vulnerability coefficients are suitable for both truss and RC frame structures. An importance coefficient based on the bearing capacity of the remaining structure is proposed to reveal the internal topology and failure scenarios, and is viewed as the weight coefficient of the corresponding vulnerability coefficient. The occurrence probability density function is introduced to describe the uncertainty of abnormal events and assess structural robustness under different events. Numerical examples of several idealized trusses and a RC frame are performed to demonstrate the use of the proposed robustness index. Analysis results show that the robustness index provided good explanation for robustness quantification for both truss and RC frame structures under different events. Moreover, two methods, i.e., increasing the local resistance and redundancy of the structure, to upgrade structural robustness also testify to the effectiveness and accuracy of the robustness index.

Buildings and their elements are designed to be used for a certain period of time (their service life), fulfilling all requirements for which they were designed without excessive maintenance costs. However, buildings begin to deteriorate because the instant they are put into use, they begin to show a progressive loss of performance until they become obsolete, having deteriorated beyond minimal acceptable levels or having failed to meet economic expectations. Nowadays, mostly for economic and environmental reasons, there is a growing concern about the durability and service life of buildings. This paper discusses the service life prediction of natural stone claddings using a Takagi-Sugeno fuzzy model. The models proposed include variables that influence the degradation of the claddings analyzed. To obtain the models proposed, samples of 140 and 203 façades were subjected to meticulous field work to determine their condition. The service life of the samples was also evaluated and the influence of the characteristics of the claddings on degradation was analyzed. This study demonstrates the usefulness of fuzzy systems to evaluate the service life of exterior stone claddings.

Full-scale single-room masonry buildings of different typology, i.e., unreinforced (URM), reinforced (RM) and Confined Masonry (CM) were tested under cyclic loading in quasi-static manner to study the seismic performance. All the indigenously built building typologies were $3.01\times 3.01\mathrm{m}$ in plan and 3.0 m in height, having exactly similar material, geometry, and construction practices. Among six tests conducted, three were on original masonry system and remaining three models were URM-repaired (URM_REP), URM-retrofitted (URM_RET) and RM-retrofitted (RM_RET), with same initial features. The observations made and the test data collected were for different damage grades and displacement capacity. The present paper focuses on the analysis of experimental results in terms of lateral load capacity, stiffness degradation, displacement ductility capacity, behavior factors and energy dissipation capacities. The failure modes observed were: sliding of brick at mortar-unit interface; discrete shear cracks in masonry walls, crushing of masonry units and bending of reinforcement in tie columns. Out of the tested specimens, CM building exhibited large initial stiffness, along with higher strength, ductility, energy dissipation capacity, behavior factor and low level of structural damage. Consequent on significant cracks, CM building showed uniform stiffness reduction, while URM structure exhibited rapid stiffness degradation with minimal increase in lateral deformation.

The 6-km-long Liefkenshoek rail tunnel creates a new freight connection in the Port of Antwerp (Belgium) by crossing the River Scheldt and Port Canal. The water level variation of the river, corresponding to the tides of the North Sea, proved to be a nonnegligible load state for the tunnel lining. This paper reports how the structural response of the Liefkenshoek tunnel to the tidal fluctuations could be identified, thanks to the various components of the complementary monitoring program, consisting of strain, ovalization, and leveling measurements. First, an in-depth study on the methodology of the applied monitoring procedures is presented. Next, results show that the tidal effect causes an oscillating vertical displacement of the tunnel lining up to 10 mm between low and high tide. Outside the river boundaries, no significant tidal influence is found, and the transition zone between the stable tunnel section and the moving part below the river appears to be constrained to a relatively small tunnel section. Furthermore, the concrete lining shows a uniform compression and relaxation between tides. The corresponding monitored stress changes show a good resemblance with results from simplified analytical calculation. The findings of this paper perfectly illustrate how the design process of segmental tunnel linings requires a thorough understanding of the project surroundings for a correct identification of all loads on the precast concrete elements, both during and after tunnel drive works.

This study conducted candlepower distribution tests to analyze the characteristics of emergency lighting. The spatial luminous intensity distribution of light intensity lamps was obtained. The experimental results for groups of samples were compared, including lighting structure, light specifications, installation, and input voltage as well as other factors affecting the optical characteristics of the lights. This study found that the impact on the surface level of illumination using different mounting directions varies greatly, with top inlay models performing better than wall-mounted lighting fixtures. A wall-mounted luminaire mounting height of 2.5 m did not meet the standards of the ground-level $21\times$ luminance values specified earlier. In addition, the study found significant differences between the emergency light’s stated power consumption and its actual power consumption at nominal power; however, the stated nominal power consumption of most commercially available emergency lighting is less than half of the actual consumption, and the total flux is only around $1/8$ of the stated value. This significant gap causes the current design of emergency lighting to be a mere formality, because the lights are unable to provide the basic lighting required for emergency evacuations. This may also cause casualties during evacuations due to equipment failure.

Although post-occupancy evaluation (POE) is an old tool with hundreds of studies, it is yet to become routine in the housing industry. The growing complexity of buildings and emerging trends in the industry further reinforces the need to carry out more POE studies. Though some studies exist, a holistic approach is yet to be given priority in the industry. This paper presents an overview of POE; it presents a broad introduction, levels of investigation, POE methods, performance elements related to the housing context, and POE tools and frameworks. It also highlights key benefits to be derived from a POE and barriers forestalling its adoption in the industry. The goal of this paper is to provide a foundation and source of reference for current research in housing evaluation studies.

An aircraft overrun occurs when an aircraft is unable to stop within the design runway length. To promote safety at United States airports, the Federal Aviation Administration (FAA) requires airports to have a runway safety area extending 1,000 ft (304.8 m) beyond both ends of the runway. However, in some cases natural or manmade barriers prevent satisfying this requirement. For these cases, one solution is to install an engineered materials arresting system (EMAS). An EMAS is a passive system constructed using low-strength cementitious blocks. Typically, an EMAS is designed for the heaviest aircraft based at the airport. Heavy aircraft fully crush the EMAS material and therefore their behavior within an EMAS is predictable. However, the National Plan of Integrated Airport Systems (NPIAS) includes many regional airports, which are supported by lightweight regional jets. Regional jet behavior within an EMAS differs from heavier aircraft. This paper investigates the EMAS performance and aircraft behavior in an EMAS of three aircraft types: CRJ200ER, B727-100, and B737-900ER. EMAS performance is measured through tire penetration and stopping distance. The CRJ200ER is a lightweight aircraft commonly used to support air travel to regional airports. For comparison, the B737-900ER is included in the study as a common narrow body, short to medium range mainline aircraft. The B727-100 is included to validate the computer code used in this paper. Although outdated, the B727-100 is similar in weight to the B737-900ER, and serves to compare the significance of landing gear parameters. The EMAS geometry and material strength of the EMAS bed at Yeager Airport in Charleston, West Virginia is used as a representative regional airport EMAS. An actual overrun incident involving a CRJ200ER at Yeager Airport is numerically modeled. These numerical results are compared with the actual event results to approximate actual braking during the event.

Concrete-faced rockfill dams (CFRDs) can be configured as concrete-faced sand-gravel dams (CFSGDs) during design and planning stages based on geological conditions and available rockfill materials at the construction site. Karacasu Dam, located in Turkey, is a pioneering example of a CFSGD and is built primarily on marl. The primary purpose of this study is to examine the monitored performance of the Karacasu Dam by using data collected from 18 earth pressure cells and 30 displacement cells embedded within the dam body, as well as 15 joint meters installed on its concrete face. This quantitative examination provides various crucial insights for building dams of this type in the future.

This paper is a case study of the Taoyuan International Airport Access Mass Rapid Transit system, the first project in Taiwan constructed with Double-O-Tube (DOT) shield tunneling. The advancing DOT shield tunneling served to induce ground settlement during construction, which thus impacted the safety of buildings and facilities in neighboring areas. A three-dimensional finite-element program was introduced to simulate the DOT shield tunneling process. Five consecutive rounds were excavated by a tunnel-boring machine from a constructed section; then the longitudinal and transverse ground surface settlements were investigated. Three soil models—a Mohr-Coulomb (MC) model, a Hardening Soil (HS) model, and a Hardening Soil model with small strain (HS-Small)—were used during the numerical analysis. Six monitoring sections along the tunnel alignment and field monitoring data were selected for the investigation. From this study, the ground surface settlements analyzed by the MC model were clearly less than those of the other two models. Because the HS-Small model considered soil stiffness to decay nonlinearly with increasing strain amplitude, it thus showed more-realistic modeling compared to the MC and HS models. This phenomenon was especially evident in the soft-soil stratum. This case study sheds some light on future projects of similar nature.

A previous study by the authors provides an overview of existing seismic risk assessment approaches and available seismic fragility information and highlights the lack of relevant information for nonengineered residential buildings. The current paper proposes a procedure for developing empirical seismic fragility curves for nonengineered residential buildings using the U.S. Geological Survey (USGS) seismic ground motion and shaking intensity maps presented in a geographic information system (GIS) format, to overcome the lack of ground motion recordings. The proposed procedure has been applied to a damage data set collected in Bantul Regency, Indonesia, in the aftermath of the May 2006 Yogyakarta earthquake. Fragility curves for nonengineered single-story unreinforced masonry (URM) residential buildings have been derived using the damage data set for the peak ground acceleration (PGA) and pseudospectral acceleration (PSA) as the ground motion intensity measures. The developed fragility curves indicate the high seismic vulnerability of nonengineered residential buildings. This study also demonstrates the potential of utilizing USGS seismic ground motion data to develop empirical fragility curves for nonengineered residential buildings in developing countries. In addition, a comparison of the results from other seismic risk assessment studies highlights the significant influence of the derivation method used on the fragility curve characteristics.

This paper describes and discusses the vibration serviceability of the innovative prestressed cable-reinforced concrete truss (i.e., prestressed cable RC truss, PCT for abbreviation) floor system subjected to heel-drop impact loading, based on the theoretical and experimental studies. In the theoretical analysis, the PCT floor system is idealized as an anisotropic rectangular plate with four built-in edges and the weighted residual method was used. A field test was carried out to investigate the dynamic characteristics of the PCT floor system and to validate and demonstrate the convergence of the theoretical solution. As a result, the experimental results agree well with the theoretical ones. The decrease of vibration is dramatic in the direction perpendicular to the PCT girder and is at a slower rate along the direction of the girder. The investigated PCT floor system has a low fundamental natural frequency ($<4\mathrm{Hz}$) with low damping ratio ($\approx 2\%$). According to one standard of vibration criteria, the innovative floor system exhibits satisfactory vibration perceptibility.

Condition indexes have been developed to measure building component condition degradation due to age, use, and deterioration in support of asset management tasks related to work identification, planning, and prioritization. With the development of these indexes, a vast amount of condition index data have been collected for a wide range of components in buildings of varying type, use, and geographic location. The U.S. Department of Defense has implemented a standardized condition-assessment approach applied to thousands of Department-owned buildings, resulting in a vast condition index dataset to support more in-depth study of building component condition and reliability. This paper explores the existing data and develops a rigorous definition of the relationship between component condition, failure, and reliability. Presented is an approach using Markov transition probabilities to analyze the existing component condition datasets. This approach provides an improved method for predicting future condition index values based on past inspection results that are not based solely on inputs traditionally prone to error, such as component age and expected service life. It also results in a reliability metric that relates to a component’s probability of failure, providing a much needed measure to manage risk.

Authorities in Quebec, Canada, have been making considerable efforts to improve sewer networks across the province by using up-to-date technologies. To rehabilitate its sewer mains, Quebec has used several rehabilitation methods including slip lining, cement and epoxy lining, and cured-in-place pipe (CIPP).These replacement and rehabilitation techniques have been developed over the last four decades, with many arbitrary declarations made about the efficiency and performance of different rehabilitation techniques. This paper presents condition prediction models for CIPP rehabilitation of sewer mains. Regression analysis technique is used to develop these models, based on gathered and analyzed closed-circuit television (CCTV) inspection reports for Quebec CIPP rehabilitations. The models can predict the structural and operational conditions of CIPP rehabilitation on the basis of basic input such as pipe material, and rehabilitation type and date. They can also generate curves illustrating condition deterioration over time with respect to governing factors. A data set was randomly selected and put aside for validating the developed models. Models validation was based on the value of the coefficient of multiple determination ($R^2$) ranging between 94 and 99%. The developed models are expected to be used by municipalities and contractors to forecast the condition of rehabilitated pipelines, plan inspections, and make informed budget allocation decisions.

In practical seismic stability analyses of gravity dams, it is common to (1) oversimplify irregular dam-rock interfaces, (2) neglect the effects of cohesion and tensile strength, and (3) ignore the effects of vertical ground accelerations. In this paper, a critical appraisal of such simplifying assumptions is proposed. For this purpose, an efficient procedure for dam seismic stability analysis not requiring the above-mentioned assumptions is first proposed. The developed technique is applied to investigate the seismic stability of an existing gravity dam with a stepped dam-rock foundation. The response of the dam is studied under the effects of two earthquakes differing by their frequency contents. The resulting stresses at the dam-rock interface, sliding safety factors, crack lengths, and residual displacements are examined. Detailed discussion of the effects of dam-rock geometry, mechanical properties at the dam-rock interface, and the vertical seismic component is presented. It is primarily shown that a simplified dam-rock geometry should be used with caution because it may lead to inaccurate results for the dam sliding safety factor and residual displacement. The results also emphasize the importance of cohesion, tensile strength, and friction in dam seismic stability assessment. The sensitivity of stress distributions at dam-rock interface to ground accelerations is illustrated. The sliding safety factor is found to be practically insensitive to the vertical seismic component, whereas dam residual displacements are more affected.

The scientific community is devoting more attention to the wide field of inspection, diagnosis, maintenance, and rehabilitation of buildings, including systems to support the inspection of buildings with anomalies. Since the activities of rehabilitation and maintenance are key factors in buildings’ sustainability, it is essential to develop a correct interpretation of defects, supported by objective and adequate diagnosis means, with the goal of significantly increasing the quality standards of potential intervened buildings and their subsequent service life. In this paper, a brief revision of the scope of building inspection systems/methods is made, presenting some of the challenges in this expertise field. From the analysis of the inspection systems/methods found in the literature, it can be concluded that they all have a similar organization but none are entirely devoted to provide expeditious and objective information on on-site interventions. The importance of establishing a reliable Building Inspection System is demonstrated as well, in order to provide easy access to the most relevant information available on building pathology.

A fracture-critical bridge along Interstate Highway 35 with a relatively high volume of traffic had exceeded its original design life and was monitored before and after a repair was implemented to strengthen the bridge. Strain gauges and crack propagation gauges were installed at critical locations near existing fatigue cracks identified from annual manual inspections. The initial data were evaluated and indicated that the fatigue life of the bridge had been exceeded, such that the bridge needed to be repaired or replaced. The bridge owner placed the bridge on a fast-track schedule for replacement; however, because it would take 2 to 3 years to complete the bridge, the bridge owner also elected to strengthen the bridge in the interim. The girders were strengthened by installing bolted cover plates between the top flanges of the longitudinal girder and transverse floor beams. The response of the bridge was monitored before, during, and after the bridge was strengthened. In the strengthened condition, the fatigue behavior of the bridge was dramatically improved due to unintentional composite behavior between the bolted cover plates and the concrete deck. Developing composite behavior in noncomposite, aging bridges may be a potential method of mitigating future fatigue damage.

One of the brilliant and exquisite structures in Iranian architecture is the Gonbad-e Qabus tower which was built on the Gorgan Plain in 1006 AD. Because Iran is located on the Alpide seismic belt and due to the presence of many faults in the region, as well as the historical, cultural, and tourism importance of the tower, examining the behavior of this structure under earthquake conditions is an important matter. To investigate the performance of the tower under various earthquake loadings, this study uses the finite-element method and nonlinear dynamic analysis as well as field and experimental tests to determine the mechanical properties of masonry blocks and the soil around the building. Accordingly, after the modeling of the tower and the surrounding soil, modal analysis, as well as static and time history analysis, was carried out under seismic records with different frequency contents. The results showed that the records with low frequency contents produced higher displacements and stresses in the tower, such that Tabasrecord, with high frequency content, and Loma-Yerba earthquake, with low frequency content, produced the maximum displacements of 13.88 and 27.57 cm, respectively. Stress contours resulting from the earthquake records in all cases exceeded the compressive and tensile strength of the tower’s materials, which indicate the necessity of seismic rehabilitation.

Expansions in concrete dams may be caused by chemical or physical sources; however, in certain occasions the evidences observed in the dam may not be attributed to a single cause. Mequinenza is an example of a concrete dam affected by expansions and high nonrecoverable displacements that cannot be explained by the most frequent pathologies. This paper presents new hypotheses that could justify such behavior by assuming the superposition of a global phenomenon of water induced expansion in concrete in the entire dam and a localized effect consisting in the opening of cracks in the construction joints located in one of the blocks. This is validated by conducting numerical analyses through 2D finite element models that consider the nonlinear behavior of the construction joints and use zero-thickness interface elements to simulate the potential cracking planes in the dam. The results confirmed the diagnosis proposed and the capability of the model to reproduce the behavior of the dam, revealing the significant contribution of the opening of the cracks to the non-recoverable displacements in the dam.

This paper presents an experimental and analytical progressive collapse-resistance evaluation of reinforced concrete (RC) frame substructures under monotonic vertical displacement of a side column, simulating a column removal scenario. A two-span, two-bay, and single-story one-third scale model representing a segment of a larger space frame structure was tested. The downward displacements of the top of the removed side column are imposed until failure. Frame collapse is defined herein as the rupture of tension steel bars in the floor beams. The study provides insight into the behavior and failure modes of the frame structure under a side column loss, including the development of catenary action in the beams and tensile membrane action in the slabs. Based on the experimental observations and theoretical analysis, a simplified calculation model of progressive collapse-resistance capacity of RC frame substructures due to the loss of a side column is established, which establishes the foundation for progressive collapse assessment of RC frame structures. The reliability of the proposed model is verified by experimental results.

Due to the complexity and uncertainty of geological conditions, a comprehensive investigation method is proposed to identify main causes of sudden increases of uplift pressures beneath local blocks of a gravity dam, which integrated statistical analyses of in situ seepage observations, inversion analyses of seepage fields using the numerical method, and field investigations. To fully identify the natural geological condition of the foundation after several years of operation, comprehensive field investigations, including core borings, water-pressure tests, and borehole television imaging, are employed. A case study of Xixi Dam is applied to demonstrate the utilization of this method. The study focuses on the local riverbed blocks, underlying which sudden increases of uplift pressures occurred in the months of April and May 2010, as well as March 2012. The primary explanation is that the coupled external loads of low ambient temperature and high reservoir water level induce the phenomenon. Further investigations show that unsatisfactory waterproofing treatments, as well as the intensively tension joints in the broken foundation rock, are the defects responsible for reservoir leakage and sudden high uplift pressures. The proposed method could be employed in investigations of similar problems of gravity dams.

In seismically active regions, the use of timber–reinforced concrete (RC) hybrid construction can overcome the structural limitations that occur with timber construction. This paper investigates three connections used in the timber frame–RC core hybrid system: (1) RC wall-timber beam connection, (2) timber column-base connection, and (3) timber beam-timber column connection. A series of monotonic and reverse-cyclic loading tests were conducted on three replicate connections. Salient features of each connection (i.e., stiffness, ductility, and energy dissipation) were computed from the monotonic loading test results and were used to set the backbone curve of the analytical Pinching4 hysteretic model. Furthermore, the Pinching4 hysteretic models were calibrated with the reverse-cyclic loading test results. Utility of the Pinching4 hysteretic models was shown with performance prediction of a portal frame test. The portal frame results showed good agreement between the finite element model using the calibrated Pinching4 hysteretic models and experimental test results.

Development of new strategies in order to prevent the progressive collapse of structures is the main focus of many studies during recent years. Due to the available complexities, most of these investigations are concentrated on static behavior of structures while most of the events leading to progressive collapse of structures are inherently dynamic incidents. In the present study, a theoretical method is developed in order to compute the dynamic resistance of reinforced concrete (RC) subassemblages, which are accepted as an idealized part of RC frames in the literature. The proposed method calculates the arching and catenary capacities of RC subassemblages under the middle column removal scenario. The high strain rates due to dynamic behavior of RC members are also considered in the proposed method. An extensive evaluation study is performed in three different stages in order to provide a comprehensive assessment of the introduced approach. Regarding the performed evaluations, the developed theoretical method could provide a reliable framework for progressive collapse analysis of RC frames under the dynamic removal of the columns.

This paper presents a holistic postoccupancy evaluation (POE) framework and its application to a campus residential facility. The development of a framework was based on an extensive review of literature and an identification of a comprehensive set of performance indicators. Multiple evaluation techniques were employed, including the review of existing documents, interviews, walkthroughs, questionnaire surveys, and spot measurements. The importance-satisfaction (IS) matrix was utilized to identify building performance successes and failures. The study shows that occupants are moderately satisfied with their residential environment. Specific issues identified were related to HVAC and lighting systems, among others. The holistic POE framework will help to derive more qualitative feedback in housing evaluation studies for more reliable decision making. This study bridges the research gap for the need for more holistic forms of POE in the facilities management sector. The recommendations provided in this paper will serve as feedback and feedforward for the building and construction industry.

The current state of the national bridge infrastructure network highlights the need for solutions to mitigate the evolution of deterioration, but also the need to develop innovative solutions to evaluate conditions on regular intervals. Solutions to this evaluation challenge need to be cost-effective and not interrupt traffic, but also need to align with current assessment strategies for adoption. The concept of remote sensing applied to transportation infrastructure evaluation presents a viable option, as the tools are noninvasive and can be used to provide analogous information to that which is typically collected through standard evaluation practices. This paper presents the results of a field study focusing on the deployment of commercially available remote sensing technologies for evaluating in-service bridges. The selected remote sensing technologies were used on three concrete bridges in the State of Michigan to evaluate the capabilities of each technology and their ability to provide condition measurements comparable to those derived from traditional hands-on inspection practices typical for in-service bridges. Results from the field study highlight that these technologies do provide comparable and even more comprehensive condition measurements in a more efficient manner than standard practice, but also highlights the need for the fusion of measurement techniques to provide a more robust condition assessment.

This study investigated the differential settlement and induced structural damage in the west extension of Nanjing Metro Line 1. The minimum and maximum cumulative settlements measured over the course of four years of operation were 1 mm and 122 mm, respectively. Four settlement troughs in the longitudinal direction of the line, as well as a periodic variation of differential settlement between the stations and the tunnel, were observed. Approximately 10% of the vertical radius of curvature of the line violates the safety limit of 15,000 m, and three typical kinds of cracks (i.e., transverse cracks in the tunnel roof and in the track bed, and inclined cracks in the outer wall) and leakage have occurred. The differential settlement of the line was mainly caused by the nonuniform distribution of underlying soft soil. The periodic variation of differential settlement between the stations and tunnel was attributed to the structural characteristics and the seasonal variation in the groundwater level. The findings presented in this paper can provide a reference for controlling the differential settlement of tunnels constructed in soft deposits.

This paper presents a diagnostic case study of a long-span bridge, which uncovered the root cause of unsymmetric vibration performance that appeared to point to deterioration. In this case study, two iterations of the structural identification (St-Id) process were applied to (1) develop a comprehensive finite-element (FE) model (inclusive of approach spans) representative of the general dynamic properties (frequencies and mode shapes), and (2) check that the response magnitudes were consistent with those expected from vehicular traffic. More specifically, this research confirmed the perceived vibration discrepancy with direct measurements, conducted a comprehensive (including approach spans) ambient vibration monitoring of the bridge, updated an FE model to match measured modal parameters, and performed a series of simulations to both validate the updated model and understand the root cause of the unsymmetric vibrations. Through this process, it was determined that the unsymmetric vibrations resulted from the approach span designs, which provided significantly different levels of lateral stiffness to the primary bridge. Additionally, upon repeating the test following the replacement of all expansion bearings with neoprene bearings, similar levels of vibration asymmetry were observed, which further supported the diagnosis that this behavior is an inherent characteristic of the bridge. In addition to introducing an iterative St-Id process that makes use of both modal parameters and magnitude information (derived from an ambient vibration test), this paper illustrates the importance of explicitly including the approach spans within the St-Id of long-span bridges. In this case, ignoring the influence of the approach spans would likely have resulted in the erroneous conclusion that some damage or deterioration within the main spans was causing the unsymmetric vibrations observed.

The data of 302 highway bridge catastrophic collapses occurring in China between 2000 and 2014 due to human causes were collected and statistical analyses were conducted from various viewpoints including accident stages (during construction or service), casualties (death or injury), location, time, life span, bridge type, and primary causes behind the accidents. Six representative collapse cases were expounded on to find out their individual peculiarities. These cases encapsulated serious problems in Chinese highway bridge engineering, including design, construction, maintenance, and management, among others. A concise review of highway bridge collapses due to human causes in China was presented. Some typical abnormal phenomena, such as those concerning entities involved in the Chinese highway bridge engineering industry, were analyzed and highlighted. Suggestions were put forward to urge all related parties to obey rules and laws to reduce and avoid bridge collapse accidents. The lessons from these bridge accidents should be fully studied to further ensure the safety, durability, and economy of bridges. This study provides a comprehensive reference of the current situation regarding highway bridge collapses in China, which is also useful for ringing the alarm bell to alert bridge owners, designers, constructors, supervisors, researchers, and maintenance crews of potential dangers.

This study has been performed to build a condition-monitoring framework of mosque physical conditions based on the cause of the defects in question. The study sample is four mosques in Malaysia: two in Kuala Lumpur and two in Putrajaya. A total of 2,276 defects were recorded. Test results of one-way analysis of variances (ANOVA) at $p=0.000$ ($p<0.05$) shows a difference of significant difference of defect causes on the level of mosque physical conditions. The biggest difference stems from the usage factor with remedial/construction, while the smallest is from usage with environment, with mean difference values of 0.625 and 0.510, respectively. This means the level of mosque physical conditions is influenced primarily by usage factor, followed by environment and remedial/construction. Usage factors consist of impact damage/vandalism, change of use, and normal wear; environment includes artificial movement/vibration, natural movement/vibration, and aging; and remedial/construction includes material selection and workmanship. This condition-monitoring framework can prevent or minimize each mosque’s physical defects. Therefore, users can conduct worship, educational, social, administrative, and economic activities that are safe, healthy, and comfortable in order to increase the mosque’s service to religion, communities, and the nation at large.

Water distribution networks have a significant effect on public health and safety. Recent reports state that the 21st century is estimated to be the end of effective life for most water distribution networks in the United States. It is essential to implement accurate and cost-effective models that can predict deterioration rates along with estimates of remaining useful life (RUL) of the pipelines, to perform necessary intervention plans that can prevent disastrous failures. This study presents a computational model that predicts the RUL of water pipelines using an artificial neural network (ANN) model that has been developed using the Levenberg-Marquardt backpropagation algorithm. The model is implemented, tested, and trained using data collected from the city of Montreal. Results show that pipeline age, condition, length, diameter, material, and breakage rate are the most important factors in the prediction of RUL. Because the model shows robustness and accuracy in estimating the RUL of water pipelines in the case study, it can be used to support the municipality of Montréal, Quebec, Canada, in future planning.

This paper reports the investigation outcomes of the recent Super Typhoon Haiyan (also known as Hurricane Yolanda) in the Philippines using a basic structure damage rating technique. The rating technique ranked damaged conditions based on a 0 to 3 rating. A total of 156 structures were analyzed using the rating technique. Unlike previously published condition ratings, the technique does not include functional assessments such as mechanical and electrical systems and does not directly consider habitant safety nor costs to structure. The intent of the rating is to provide a quantitative measure of the effects of Haiyan. The outcomes indicate that wind damage dominated as the major cause of failures (53%) and that roof damage is the most significant of the damage modes (21%). The rating gives a first-order assessment of the damaged conditions of the structures pertaining to the loading effects (wind, water or storm surge, or combined) from Super Typhoon Haiyan.

Climate change and an increase in the number of hazards and/or their intensities may increase the probability of failure associated with civil infrastructure systems. Understanding how natural hazards affect the life-cycle performance of highway bridges can lead to improved preparedness prior to extreme disasters and can ultimately benefit society. In this paper, a framework for time-variant loss and resilience assessment of highway bridges under time-dependent multiple hazards is presented. The effects of earthquakes and floods on bridges are both investigated. The life-cycle hazard losses with and without aging effects and climate change are computed. Additionally, the probabilistic changes in the hazard intensity and frequency resulting from climate change on the total life-cycle hazard loss are also investigated. The proposed framework is applied to a highway bridge located in California.

A nonductile reinforced concrete (RC) frame was constructed and was subjected to a predefined level of damage by subjecting the frame to simulated earthquake loading. The damaged RC frame was then subjected to 1-h designed compartment fire. The RC frame was instrumented with a number of sensors that recorded strains, displacements, and temperatures during the test. The resulting data provided a distinctive record of earthquake-damaged RC structures in fire through a complete heating–cooling cycle. The experimental results were compared with the results from an earlier test done on the RC frame having ductile detailing. The results show a marked influence of reinforcement detailing on the postearthquake fire performance of the concrete structures. The simulated earthquake loading caused wider cracks and more severe concrete spalling in the frame without ductile detailing compared to the frame with ductile detailing. The fire damage was also more pronounced with extensive spalling due to the attainment of higher temperatures in the structural elements of RC frame constructed with nonductile detailing than the frame having ductile detailing.

The driving security of trains at high speeds is among the pivotal issues significantly affected by the smoothness of rail lines. For high-speed railway steel bridges, the fatigue cracking of typical positions under the rail lines will reduce the stiffness of the deck plate, inducing the smoothing of the rail lines. In this paper, a new theoretical approach is proposed that integrates the fatigue assessment of a typical welded joint for high-speed railway steel bridges in service. Based on the strain history data recorded by a structural health monitoring system, the theoretical approach includes various factors, including stress concentration, environmental corrosion, and train flow. Upon application in an actual high-speed railway bridge with an orthotropic steel deck, the approach was used to conduct determinative and reliable fatigue-life evaluation of the bridge. A static-load experiment was conducted to obtain the stress distribution around the weld and the difference in stress between the positions of the weld and strain gauge. The effect of environmental corrosion integrated two aspects: increased stress and reduced fatigue resistance. Without consideration of train-weight growth, in conclusion, the fatigue life of a typical welded joint will be infinite even if the train flow grows constantly. In addition, the fatigue life of typical welded joints, determinative or reliable, may be less than the designed service period when the growth rate of the train weight reaches 5%.