Journal of Performance of Constructed Facilities

Because of weak surrounding rock, tunnels constructed in loose deposits are prone to collapse, and secondary linings commonly suffer excessive deformation. Therefore, it is important to select an appropriate excavation scheme, which will affect both tunnel construction safety and subsequent tunnel operations. This paper takes the Tingziba tunnel, a highway tunnel shallowly buried in loose deposits of diluvial and proluvial origin, as an example. During construction, this tunnel experienced many instances of vault collapse and advanced support destruction. Isotropically consolidated drained (CD) compression tests were carried out on reconstituted specimens to obtain the mechanical parameters of the loose deposits. Three-dimensional modeling was performed to simulate stress and deformation distributions in the tunnel after excavation by three different schemes, i.e., up and down bench tunneling, three-bench tunneling, and single-side heading tunneling. The comparative analysis results showed that single-side heading tunneling was more suitable for this tunnel and could both reduce vault displacement and constrain plastic zone development. The results should be significant for tunnel design and construction in similar geologic environments.

Acoustic emission was used in this study to assess the condition of a simple-span, prestressed concrete bridge located in southern New Mexico during a proof test. The 40-year-old bridge is county owned and no design plans were available. Acoustic emission (AE) data were collected under several loading conditions from two groups of sensors placed near the support and midspan of an interior double-tee beam. Strain measurements were also taken at midspan and used to direct the test and determine the maximum loading. AE data analysis methods were applied to evaluate the response of the structure under increasing loads and to develop crack maps. Analysis of the AE data showed signs of internal beam microcrack development near the supports (shear region) as well as in the midspan (moment region). The AE data indicated that damage in the form of crack growth was more prevalent in the region near the supports.

Northwest Arkansas Regional Airport (International Air Transport Association Code, XNA) opened in 1998. XNA is a regional airport serving the northwest Arkansas area. Alkali silica reaction (ASR) was detected at XNA’s runway 16/34 in 2002, and in 2012 the runway was closed for replacement. The airport includes a single runway; therefore, runway replacement required the construction of a temporary alternate landing surface (ALS). Consequently, costs related to the premature runway replacement were substantial. XNA is experiencing significant pavement distress caused by ASR. Therefore, in addition to the runway, taxiways and apron areas will require replacement. The article reviews ASR, causes of ASR at XNA, and a preliminary investigation to develop a remediation approach to ASR at XNA. For ASR remediation, the authors are investigating various surface sealants for their effectiveness to retard ASR, to provide XNA operators additional time before future pavement replacement is warranted.

An explosion occurred at a fertilizer plant in the town of West, Texas, on Wednesday, April 17, 2013, devastating a populated neighborhood. A total of 15 people were killed, and approximately 160 people were injured. Approximately 150 buildings were damaged in the explosion. The damage to affected homes and businesses was estimated to exceed $100 million. The purpose of this study was to collect on-site technical data of the explosion and gain knowledge of blast loadings and structural responses from this unprecedented explosion. Specifically, this research documented the building damages caused by the West Fertilizer plant explosion and the affected buildings’ construction and materials and evaluated the technical information for the explosion, including the blast loadings, i.e., the air-blast incident overpressures and ground shocks, on different buildings with respect to the standoff distances. A total of two technical papers have been prepared. The Part I paper (this manuscript) focused on the building damage documentation and air-blast incident overpressure estimation for the West Fertilizer plant explosion case. The Part II paper focused on the effects of the ground shock caused by this West Fertilizer plant explosion.

An explosion occurred at a fertilizer plant in the town of West, Texas, on Wednesday, April 17, 2013, devastating a populated neighborhood. A total of 15 people were killed, and approximately 160 more people were injured. Approximately 150 buildings were damaged in the explosion, and the damage to affected homes and businesses was estimated to exceed $100 million. This research documents the building damages caused by the unprecedented explosion and evaluates the technical information for the explosion. The Part I paper of this research focused on the building damage documentation and air-blast incident overpressure calculations. As a companion paper, this manuscript (Part II) primarily focuses on the study of blast-induced ground-shock effects. The ground shock–induced building damages and ground vibration peak particle velocities (PPVs) are analyzed. With a combined consideration of these two types of blast loadings, the air-blast incident overpressures and ground shocks, the field investigated damages caused by the West Fertilizer plant explosion are explained in a more precise manner. The air-blast incident overpressure is identified as the dominant factor for the damages of both wood light-frame buildings and engineering buildings. The ground shock is the secondary factor but is still important. Concluding the research outcomes in the Part I and Part II papers, this study proposes a four-scale blast-induced damage severity evaluation system, demonstrates efficient blast-loading calculation methods for both the air-blast incident overpressure and ground-shock PPV, and provides a correlation between the blast loadings and the blast-induced damages for the West Fertilizer plant explosion case. The documentation and analyses that resulted from this research could serve as a good case study for better understanding of the blast loadings and building structural responses.

The reported experimental study documents the performance of six fully grouted reinforced concrete block structural walls tested under quasistatic cyclic loading. The walls fall under the ductile shear walls and the special reinforced masonry walls seismic force resisting system (SFRS) classification of the Canadian and U.S. standards, respectively. The test matrix consisted of one rectangular, one flanged, and two slab-coupled walls, all with an overall aspect ratio of 1.4. In addition, two rectangular walls, representing the individual components of the slab-coupled wall systems, were tested to quantify the wall slab coupling effects. In addition to discussing the experimental results, the study also presents key force-based seismic design (FBSD) parameters, such as the wall lateral load capacity, plastic hinge length, wall failure modes, and displacement ductility capacities. Moreover, the effects of wall cross-sectional configuration and slab coupling on the cyclic response and deformation capabilities of the walls are discussed. In general, the yield and ultimate loads were found to be accurately predicted using the Canadian Standards Association (CSA) S304-14 and Masonry Standards Joint Committee (MSJC) formulations. The wall experimental displacement ductility values (calculated at 20% strength degradation) ranged between 5.4 and 7.6, whereas the idealized displacement ductility values at the same strength degradation level ranged between 3.4 and 5.4. The analysis results reported in the paper highlight the fact that walls designed and detailed within the same SFRS classification possess significantly different FBSD parameters. The results also indicate that slab coupling, although not recognized as a wall coupling mechanism in the current editions of the CSA and MSJC, can have significant influences on the seismic response of ductile/special reinforced masonry wall systems.

A typical seismically designed reinforced masonry building is composed of structural walls, constructed following the same prescriptive detailing requirements corresponding to a code classified seismic force resisting system (SFRS). However, due to architectural requirements (i.e. to allow for requirements such as openings and wall intersections), some of these walls might have the same overall aspect ratio but differ in their cross-section configurations. The companion paper presented the experimental results and force-based seismic design parameters for walls that fall under the Canadian Standards Association (CSA) ductile shear walls and the Masonry Standards Joint Committee (MSJC) special-reinforced walls SFRS classifications. The current paper utilizes the experimental results to extract key displacement-based seismic design parameters, including wall yield and ultimate curvatures, wall displacements at yield and at the post-yield stages, stiffness degradation, period elongation, and equivalent viscous damping. The paper also identifies different damage states and links them to wall drift levels, as well as the extent of plasticity within the wall base region as key performance-based seismic design parameters. The study showed that using a mechanics-based approach, the curvature ductility values were at least double the theoretical code values predicted for most walls. In addition, within the same SFRS classification, walls having the same overall aspect and reinforcement ratios will possess significantly different displacement-based seismic design parameters, which would subsequently influence their predicted response under seismic events. Moreover, the results showed that slab-coupled masonry walls showed an enhanced overall performance compared with the rectangular and flanged walls tested. Subsequently, it is suggested that future editions of the CSA and MSJC account for the effects of varying the wall cross section and slab coupling influence on the seismic response of ductile/special walls SFRS classifications.

This study examines the effect of a seismic retrofit on distortion-induced fatigue cracking in a steel girder bridge in the Midwestern United States. The seismic retrofit of the bridge was deemed necessary following a structural review initiated by the Federal Highway Administration (FHWA) in response to the 1989 Loma Prieta Earthquake. Following the review, the bridge was modified using a conventional seismic retrofit strategy to meet the 1995 FHWA standards for survivability and seismic performance. Upon completion of the retrofit, subsequent inspections identified new cracks (at the location of the retrofit) in the webs of longitudinal girders at transverse stiffener locations in an area known as the web gap. This study investigates the influence of the seismic retrofit strategy on crack formation by comparing principal stresses in the web-gap region of the original and retrofitted bridge under dead, live and thermal loading. A three-dimensional linear-elastic finite element analysis of the bridge before and after the retrofit is presented with results obtained from a commercial finite element software package. Comparisons of stresses before and after the retrofit indicate a measurable increase in stress near the web-gap region attributable to thermal and live loads following the retrofit. In addition, several viable repair strategies to limit these web-gap stresses and subsequent distortion-induced fatigue are presented. The results to date clearly demonstrate the importance of considering fatigue-sensitive details in seismic-retrofit strategies.

Ground-penetrating radar (GPR) is a rapid technology for evaluating condition of concrete bridge decks subject to rebar corrosion. In this paper, based on a threshold model recently proposed in the literature, a bridge deck corrosiveness index (BDCI), is developed to have an idea where a bridge deck is during its continuous service life and to suggest corresponding maintenance activity. Based on fuzzy set theory, expert opinions were used to calibrate fuzzy membership function for each condition category found by GPR. Then, for a particular bridge deck, area percentages of all condition categories would be utilized to aggregate these functions into a BDCI using weighted fuzzy union (WFU) operation. The benefit of the developed system is twofold. First, it is based on GPR, a more accurate inspection technology. Second, it employs the knowledge provided by bridge community, and, in the meantime, has the capability to deal with fuzzy information associated with expert responses. Using an automated software, the system is illustrated for several concrete bridge decks in North America. Because the case studies show that the developed system is easy to be implemented, it would be an effective tool for transportation agencies in North America where the corrosion of rebar in concrete bridge decks is one of biggest concerns.

The use of helical pile foundations has widely expanded in recent years. However, the prediction of the load-displacement performance of helical piles under uplift loading for service-level displacements is still a challenge for designers. In this work, a probabilistic power law model is used to characterize the random nonlinear uplift load-displacement relationship of deep helical piles. Model parameters are found from a database of 30 uplift loading tests conducted on helical piles in Brazil. Using structural reliability concepts, a practical example of a transmission tower foundation is provided to illustrate the use of the developed probabilistic model for serviceability limit state (SLS) evaluation of helical piles. The investigation takes into account the uncertainties of three parameters: one parameter of the load-displacement curve, the empirical correlation between pile capacity and installation torque, and the wind loading on foundations of transmission lines. For the example evaluated, the reliability indexes increase with allowable displacements. Additionally, the shape of the load-displacement curve is shown to be relevant when small allowance displacements are specified. In addition, when the allowable displacements approach the failure criteria for the ultimate capacity of the foundation, the developed service limit state model converges naturally to the ultimate limit state model. The structural load is found to be the random variable with the largest contribution to failure probabilities, especially for larger allowable displacements.

Many uncertain factors in the excavation process may lead to excessive deformations and internal forces of retaining structures; therefore, the design of deep excavations should be adjusted according to real-time monitoring data. This paper presents a case study of dynamic control of excavation deformations. The preliminary design adopted bored piles as retaining structures braced by three levels of steel-reinforced concrete struts, while the final design used only two levels of struts to reduce the construction duration. The final design reduced the safety degree of the project to a certain extent and brought the excavation to a state of emergency. Fortunately, the designers adjusted the excavation sequence based on feedback information from the field monitoring data. In addition, a variety of deformation control measures, aimed at reducing the horizontal displacement of the retaining walls, were used, such as strengthening the chamfer of the retaining structures, adjusting the excavation sequences, and strengthening support nodes. The monitored excavation performance demonstrated that these remedial measures were feasible and effective for controlling excavation-induced deformations and minimizing the relevant risks.

The state-of-the art paper provides an extensive literature review on the work pertaining to structural health monitoring (SHM) systems used to investigate the structural integrity of highway bridges. The focus of this review is on identifying the SHM research efforts that include damage detection, structural capacity evaluation, and remaining service life estimates on such structures. These efforts have spanned a broad range of data processing methods devoted to tracking changes in structural characteristics for damage detection, codified frameworks enabling structural capacity estimating, and reliability analysis to predict remaining life. Our findings are that a large number of studies considered damage detection by data processing methods, whereas a relatively small number of studies were devoted to the estimation of structural capacities and the remaining service life of bridges. We conclude that the critical gaps include a lack of validated SHM systems that use ambient data to examine design code-based structural integrity and remaining life of highway bridges.

Overall performance of energy infrastructure in the United States has been assessed as D+. More than 65% of America’s energy is transported through the oil and gas pipelines, which have experienced more than 10,000 failures during the last three decades. There is a critical need for a failure prediction tool that can forecast the consequences of the hazardous failures. Failure of gas pipelines has become the subject of interest for some studies in the past. Previous studies mainly focused on physical models that need inspection data or developed subjective models. This paper aims at developing a model to forecast the consequences of the potential failures of such pipes using the historical data of the U.S. gas pipes network. The model applies a neurofuzzy technique in order to recognize the existing pattern among the input and output variables. It estimates the financial consequences of various failure scenarios for specific pipes in terms of size and specified minimum yield strength. For this purpose, a bowtie model is developed, and all possible scenarios of failure are identified. Various combinations of the identified factors and different number and types of membership functions, are applied in order to optimize the model’s efficiency. The developed model is validated with an approximate accuracy of 80%. This study assists practitioners and academics who are working on the risk assessment of gas pipelines to plan for their lifecycle inspection.

Temperature field data from the steel truss arch girder and longitudinal displacement data from six groups of rubber bearings were collected by the structural health monitoring system for the Dashengguan Yangtze Bridge. By using long-term monitoring data, two correlations are investigated: the linear correlation between the longitudinal displacement and the temperature field (including uniform temperature and temperature gradient); and the linear correlation of the longitudinal displacements in different locations. A multivariate linear regression equation is used to model the first correlation, and a Lagrange polynomial interpolation is used to model the second correlation. The final mathematical models, representing the healthy state of the bearings, can be applied to simulate the longitudinal displacements of the main girder. Furthermore, the change regularity of longitudinal displacements for the degraded rubber bearings is revealed taking advantage of a hysteretic model and presumed envelope curves of frictions caused by bearing degradation. A method of detection and location for the degraded bearings is proposed in four detailed steps, and the numerical results demonstrate that this method is effective.

Wave overtopping in rubble-mound breakwaters is an aspect that must be controlled in order to ensure the correct operation of port facilities. This manuscript shows a photogrammetric methodology to automatically monitor this process based on the use of low-cost cameras. Cameras are used for acquiring video of breakwaters. Then, image processing algorithms based on binarization tresholding and projective transformation, combined with geometric data of the structure provided by the facility manager, are used to evaluate the run-up height and automatically detect the existence or absence of a overtopping event. The methodology was successfully tested in the outer port of Punta Langosteira, A Coruña, Spain.

A computational fluid dynamics–based numerical parametric study for the characteristics of the solitary wave–induced forces on typical coastal twin bridge decks is conducted in this study. At first, the second-order solitary-wave model is developed followed by a verification process with the analytical one and a related experimental study. The laminar flow model and shear stress transport (SST) $k\text{-}\omega$ model are adopted and the comparisons of their results demonstrate that they can make close predictions for the bridge deck forces. Then, the general characteristics of the wave forces for a fixed deck gap and variable deck gaps with different still water levels (SWLs) and various submersion coefficients are observed. In addition, the characteristics of the wave forces on the landward bridge deck are presented by normalized factors based on the wave forces on the seaward deck. Finally, the hydrodynamic interference effects between the twin bridge decks are investigated and the effects of the deck vibration on the wave forces are demonstrated to represent more realistic scenarios in the field. This work provides engineers one possible criterion for judging or rating the magnitude of wave forces that will be exerted on the landward deck and the vulnerability of the twin bridge decks. This work also shed some lights on the revisions of the AASHTO code in 2008 regarding the wave forces on the twin bridge decks.

Probabilistic risk assessment (PRA) is essential for evaluating different options for blast risk management. However, depending on the risk management approach being considered, a rigorous blast PRA study can be quite demanding. To expedite this process, a simplified PRA framework is proposed for reinforced concrete-block shear wall buildings, in order to determine design basis threat (DBT) fragility curves based on revised damage limit states most suitable for risk assessment. The current definitions of damage states by North American standards for blast resistant design involve global response limits—such as the support rotations of a structural element—that are relatively simple to calculate. However, such damage state descriptors can be insufficient for the cost-benefit analysis required to evaluate different risk mitigation options. As such, building on recent advances in the area of performance-based seismic design of concrete-block shear wall buildings, this study proposes revised damage states that can be associated with more useful metrics, including repair technique and building downtime. To illustrate the proposed methodology, a hypothetical shear wall building is analyzed under different DBT levels. The DBT fragility curves are obtained through Monte Carlo sampling of the random variables describing the shear wall system and are used to identify the locations that are most suitable for the erection of barriers for blast protection. The proposed PRA framework can be used to identify target performance requirements, formulated in terms of stakeholders’ tolerable probability of failure and consequent risk management, for different classes of buildings under a range of DBTs.

This study presents an approach to develop sigmoidal family pavement performance models (pavement performance ratings versus pavement age) for a pavement management system (PMS). Pavement condition data collected from windshield surveys oftentimes suffer quality issues stemming from human subjectivity, and pavement age sometimes not being properly reset after a treatment. These issues can be systematically addressed by the proposed approach, and nonlinear sigmoidal family performance models can then be developed using the cleaned condition data. In a case study, this approach was successfully applied to a sample data set extracted from the North Carolina Department of Transportation (NCDOT) PMS. Contour plots developed for the raw data and the cleaned data showed that the data cleansing process was effective. Goodness-of-Fit indicators and cross-validation suggest that the resulting nonlinear sigmoidal models fit the condition data well.

Recent Italian collapses have revealed that hidden defects can be the cause of ruinous and apparently unpredictable failures. In this scenario the necessity of a structural vulnerability assessment at the territorial scale arises. Considering that the scale of the analysis is territorial, a multilevel approach seems to be the most effective and useful because it allows calibrating the available resources. In this article a methodology for rapid structural vulnerability assessment for service loads at the territorial scale is proposed. It is based only on the acquisition of poor data (i.e., construction year, structural typology, and building location) and it is part of a wider research project of the Politecnico di Bari whose main aim was to evaluate the critical aspects of the Italian school heritage. The proposed methodology, although of general validity, is specifically presented for schools. The applicability is demonstrated with reference to the province of Bari, Italy.

Premature deterioration of civil infrastructure structures in the harsh environmental conditions of marine regions (high humidity, high thermal variation, acidic attacks, high reactivity chemical reactions, improper usage, and natural disasters) leads to the reduction of service life of these structures. Failures in the rehabilitation process have been observed are primarily attributable to insufficient rehabilitation treatment, improper selection of repair materials, and incorrect repair implementation on the structures themselves. To design a suitable repair solution, it is essential that the physical, mechanical, chemical, and electrochemical properties of the repair materials and base (substrate) concrete match properly. In this paper, a novel approach for selecting proper mix design for repairing and maintaining deteriorated concrete structures located in the marine regions of southern Iran has been proposed using multi criteria decision making (MCDM) methods. The technique of random generation (RG) has also been used for uncertainty analysis on the final results. The results of the case study showed that the proposed methodology can be used as a proper tool for the decision making process in similar repair projects.

The lifecycle analysis and assessment of concrete structures requires an efficient evaluation and prediction of time-variable mechanical and chemical degradation processes. Inspection systems and novel monitoring methods are of valuable support in these important tasks, but due to their practical feasibility and the costs that they entail, they also present limitations. Therefore, information gathered with inspection methods for structural performance assessment needs to be used in the most effective manner possible, e.g., with respect to serviceability limits, bearing capacity, robustness, and redundancy of a given structure, among others. The aim of this paper is to present a framework for the prediction of time-dependent performance indicators of concrete structures prone to fatigue, with emphasis on a wind turbine foundation, including reliability. A theoretical background and selected structural performance indicators as well as associated lifecycle prediction methods—incorporating inspection and monitoring information—are presented.

The main objective of this paper is to study the dynamic performance of seals and the fatigue failure probability updating of a hydraulic steel sluice gate by experiments. First, water seal modifications involving of top, side, and bottom water seals and the rotation hinge water seal were performed in order to identify and test for the desired shape and functionality. Water sealing experiments under a variety of conditions were performed. It is indicated that the preset compressive deformation of various water seals changed at varying water head conditions. Moreover, the transformation law of the preset compressive deformation of different sealing parts under the reservoir water head was discovered. Second, a hydraulic steel gate’s fatigue reliability was evaluated based on Bayes’ theorem. The findings indicate that fatigue cracks can be detected for existing structures while the fatigue reliability assessment can be updated by nondestructive testing (NDT). Based on the probabilistic characteristics for NDT techniques and Bayes’ theorem, a fatigue reliability updating assessment model for existing steel gate components is proposed. The results showed that fatigue reliability will increase with no cracks detected, decrease with unknown cracks detected, and change remarkably with cracks detected.

Sand-cement emerged in the early twentieth century as an alternative binder in infrastructures that required a significant amount of concrete volume in order to reduce the costs associated with portland cement. This binder was first used in the United States in several dams before being applied in Camarasa Dam in Spain. Nearly a century after its construction, the dam exhibits degradation phenomena in the downstream face, manifested by losses of mass. The present study aims at assessing the state of the sand-cement concrete in Camarasa Dam and evaluate whether the degradation observed could affect the safety and functionality of the 95-year-old dam. For that, the state of the art on sand-cement is reviewed and an experimental program of physical, mechanical, and chemical tests is performed on samples from the dam. The results reveal that the degradation phenomena may be attributed to physical causes and a general degradation of the concrete properties is discarded as well as any effect on the safety and functionality of the dam.

The EF5 tornado that occurred in Moore, Oklahoma on May 20, 2013, provided a rare opportunity to study the effects of multiple major tornadoes on a single community in a relatively short timeframe. Data collected immediately after the tornado indicate an ordered progressive collapse mechanism for residential wood-frame structures with slightly different progressions for low-pitch and high-pitch roofs. This failure progression indicates that a continuous load path from the roof to the foundation is the most important aspect of design and construction for tornado resistance of residential structures. Performance of homes in a neighborhood constructed using more-robust methods indicates that the damage path caused by an major tornado can be narrowed by improving the overall structural system with a series of relatively simple items. Twelve code modifications proposed by the authors to create a more-robust structural system intended to withstand winds up to $60\mathrm{m}/\mathrm{s}$ (135 mph), or an EF2 rating, are presented in this paper. The city of Moore adopted these code changes on March 17, 2014.

The design and anticipated end-bearing capacity of postgrouted drilled shafts hinge on achieving sufficient grout pressure applied to the soils beneath the shaft tip. Implied, however, is that the grout is distributed reasonably well across the entire tip area. To this end, minimum grout pressure and volume thresholds are usually prescribed in an effort to address both concerns. Unfortunately, it is difficult to practically ascertain the actual area of the grout bulb during production grouting when manually-recorded values of pressure, volume, and uplift are the only available information. Therein, artificially-high grout pressure can be recorded, resulting from a blocked grout-distribution system that goes undetected and the shaft is accepted as both the minimum pressure and volume criteria were satisfied. This article outlines minimum monitoring practices and field quality-assurance/quality-control (QA/QC) measures that can and should be used to better ensure tip grouting is performed in conformance with the designer’s expectations and intended outcome. The value of the proposed standard of care is highlighted through case studies where drilled shafts for bridge foundations were constructed, grouted, and met all acceptance criteria but where they were not grouted satisfactorily.

The performance concept implies that the requirements of a building are defined according to the outcomes of the process rather than according to either the method of construction or maintenance activity. An innovative performance-based contract (PBC) for outsourcing maintenance may be very cost effective due to contract flexibility and reduced management costs. The objectives of the present research study were to develop and implement a framework for a maintenance sector PBC in a sample of 13 courthouse buildings in Israel. To monitor the results, six key performance indicators were adapted and were used both for model implementation and for comparison between performance-based and unit-price contracts. The research study demonstrated a consistent improvement in the performance of the facilities operating under PBC, as well as a 20–40% improvement in the performance-cost ratio. The framework proposed here can be modified for different public buildings, and the performance model could be expanded to consider various categories of performance and risk.

The increased demand for resilient infrastructure under accidental or deliberate explosions has resulted in the urgent need to quantify the performance of both existing and new building components under such extreme loading events. The current study focuses on evaluating the resilience of reinforced masonry (RM) shear wall systems under blast, which is accomplished by quantifying the walls’ blast response in the out-of-plane direction and the resulting damage levels. In seismic zones, such RM walls are detailed to resist in-plane loads in a ductile manner, and thus minimal damage is usually expected. Given that blast resistant design of civilian buildings only recently has been formally introduced in North American design standards, quantifying the out-of-plane response and ductility capacities of RM shear walls has not been common practice in mainstream building design. In this paper, a nonlinear single-degree-of-freedom (SDOF) model is developed to predict the out-of-plane response of RM wall components under blast loading. The SDOF model is first validated by using live explosive (free-field) test results. Subsequently, the model is used to perform a numerical investigation beyond the range of experimental parameters adopted in the test program, by considering a number of wall design characteristics such as wall reinforcement ratio, concrete block size and strength, wall height, and reinforcement arrangements; a wider range of design basis threat levels––identified by charge-mass and standoff-distance combinations––is also considered. In general, the study indicates that RM walls are capable of withstanding substantial explosions, which would result in different damage intensities depending on the wall vulnerability and blast hazard levels. The study also shows that significant reduction in the wall out-of-plane response can be achieved by using two layers of reinforcement instead of the typical single layer in RM walls, even in the case of reduced reinforcement ratio. The SDOF model is also used to develop RM wall performance charts that can be further refined to serve as design guidelines for the purpose of blast risk mitigation in future editions of the North American blast design standards. Finally, the findings from this study indicate that RM walls that are detailed to respond in a ductile manner under in-plane seismic loads might not necessarily exhibit a ductile response when subjected to out-of-plane blast loads. The latter observation highlights the importance of adopting a holistic multihazard design approach when evaluating the vulnerability and resilience of building systems under extreme events.

Scouring around bridge piers is an important safety issue of bridge management since it can lead to bridge slant and collapse. Therefore, bridge scour depth is an important index to determine a bridge’s safety condition. However, directly measuring the scour depth is difficult due to the water surrounds bridge piers. Several researchers have discovered the bridge natural frequency, a proxy measurement that can be used to determine the scour depth of the bridge pier. In this study, two finite-element models including the complicated finite-element model and the simple soil spring model are introduced to compute the natural frequency of a bridge and the result is verified with field experiments. In addition, a series of simulations is then implemented to analyze the factors impacting scouring depth. Seven factors related to bridge substructure and soil property are identified. A support vector machine (SVM) is further employed to understand how those factors impact the safety of the bridge. The results show that by hybridizing the simple soil spring model and SVM, the bridge’s safety level can be efficiently established.

Situations in which deep excavations are made adjacent to metro stations in service are common in the development of underground space. However, the structural responses of existing metro stations to adjacent deep excavations and their safety criteria are still not fully understood. Through a series of numerical parametric studies and comparisons with case histories reported in the literature, this paper examines both the structural forces and differential displacements of existing metro stations induced by adjacent excavations. To consider the effect of stress history, the hardening soil small-strain model (HSS) was employed, and the building process of existing metro stations was included in the numerical simulations. The effects of key factors, e.g., the distance between existing metro stations and new excavations and the depth of new excavations, governing the responses of existing metro stations to adjacent excavations are investigated and quantified. In addition, the barrier effects of existing metro stations on the deformations of adjacent excavations are also investigated. On the basis of the numerical analysis results, some major findings were obtained: (1) excavation depth, $H_e$, and distance from the existing metro station, $D$, were the key factors affecting the structural responses of an existing metro station to the adjacent excavation; (2) the rotation and shear effects of an existing metro station induced by the adjacent excavation varied with $D/H_e$ and could be reversed in direction; (3) the bending moments in critical sections changed with $D/H_e$ and the additional bending moments in the sections had a linear relationship with the rigid column rotations; and (4) because of the barrier effect of the metro station, both lateral wall deflections and ground surface settlements induced by the adjacent excavation on the side of the metro station were smaller than those without a metro station nearby. The findings yielded from this study should provide practically useful references for engineers to assess the structural performance and rail safety of existing metro stations affected by adjacent excavations so that appropriate countermeasures can be adopted.

The deterioration of water pipelines leads to impaired water quality, increased breakage rate, and reduced hydraulic capacity. The planning of maintenance programs for water pipelines is essential to minimize health and safety concerns and ensure an adequate supply of water in a safe, cost-effective, reliable, and sustainable manner. It is essential to assess the performance of water pipelines to assist municipalities in planning inspection and rehabilitation programs for their pipelines. Several models have been developed to assess the condition or performance of water pipelines based on several affecting factors. However, none of them considered the interdependency relationships between the factors. Moreover, some models did not account for the factors’ weights uncertainty. This paper presents the development of performance assessment models for water pipelines. The models consider three groups of factors affecting water pipeline performance, namely, physical, environmental, and operational. The models were developed using data collected from questionnaire surveys distributed among water pipeline experts in Qatar. The factors’ weights were calculated using four different methods, namely, analytic hierarchy process (AHP), fuzzy AHP (FAHP), analytic network process (ANP), and fuzzy ANP (FANP). The results showed that the FANP is the most accurate method since it incorporates the interdependency and uncertainty into the decision making process.

This paper presents the results of an interdisciplinary study carried out on Brunelleschi’s Cupola of Santa Maria del Fiore in Florence, Italy, one of the most emblematic masonry domes in the world. The cupola has been affected since the beginning of its construction by a widespread cracking phenomenon, and several studies were done over the centuries to clarify its safety conditions. To have a direct and indirect record of the cracks opening or closing, a complex monitoring system was installed on the monument during the last century. An accurate analysis of crack widths and global displacements, performed considering both historical and recent monitoring data, has allowed for the identification of the movements developed in the monument, evaluating their relationship with environmental and seismic events. In line with the interdisciplinary approach strongly recommended in the field of assessment and conservation of monumental heritage, this paper reconsiders some issues concerning the causes of the actual damage to the cupola. In particular, in light of the obtained results, the famous seventeenth century Viviani’s conclusions about the cupola’s damage, confirmed by Chiarugi in the 1980s, are compared with other hypotheses, such as the differential settlement of pillars (Cecchini in 1698 and Ximenes in 1757) and the influence of temperature variations (Nervi in 1934). The large amount of measured data and the results of the last numerical models of the cupola, combined with recent dynamic measurements, allowed the updating of some previous conclusions on damage causes and trends. Starting from these conclusions, a more reliable forecasting model of the monument can be set up that could be useful in identifying effective conservation strategy for this outstanding monument.

The paper investigates the structural performance of a seven-story reinforced concrete (RC) building that collapsed during the Van (Turkey) earthquake on October 23, 2011, using nonlinear static and dynamic methods. The selected RC building has two blocks and was designed according to the Turkish Earthquake Code (TEC) in 1975. The site investigation included sections and steel detailing and soil and concrete properties taken after the earthquake. The pushover and nonlinear time history analyses of the building were completed using the existing plan and test and observation data. It is concluded that the building collapses both analysis types.

The healthcare industry is growing in complexity, and providing a safe healthcare setting increases the challenges for many healthcare facility managers. Most facility information is not linked to the healthcare delivery process, making it difficult to identify interactions and overlaps that may have critical implications for the smooth operation of the healthcare delivery process and patient safety. This paper focused on an impact analysis of facility failures on the healthcare delivery process and involved a combination of research methods including a case study, interviews with key healthcare practitioners as part of a case study in a major hospital, and cognitive walk-throughs with domain experts. The interactions of facility information with the healthcare delivery process helped to identify critical facility failures through planned and unplanned safety events. Use cases, use-case diagrams, scenario interaction diagrams, and failure mode and effects analysis (FMEA) were developed to learn and assess the functionality of the healthcare system communication related to the planned and unplanned events, and a number of factors associated with the facility failures were recognized.

The National Historic Covered Bridge Preservation Program (NHCBP), sponsored by the Federal Highway Administration (FHWA), was established to preserve the covered timber bridge structures that were constructed in the early 1800s. Today, many of the approximately 880 covered timber bridges still in existence in the United States are closed to vehicular traffic; furthermore, a large percentage of the remaining bridges open to traffic are restricted by load postings. Unfortunately, there are no current load-rating standards for covered timber bridges, so engineers do not have many resources at their disposal to reliably understand the behavior of these complex structures. As a result, the estimated load postings and/or ratings are often too conservative. To better understand the live-load performance of covered timber bridges and to develop improved criteria for their load ratings, a series of live-load tests were performed on 11 single-span, historic covered timber bridges. This paper explains the field testing conducted on all of the bridges, and makes recommendations for the conduct of other similar tests. The tests consisted of installing a network of multiple displacement and strain sensors on the structures, and monitoring global displacements and member strains at various cross sections during passage of a known test. The vehicle used in the testing met the load restrictions in place at the time of testing. The results of this work serve as a basis for instrumentation and field testing, to investigate the live-load performance on such bridges. This paper outlines the field-testing methods and summarizes the results from the testing of all 11 bridges. Based on the field-testing methods, a field-testing protocol is recommended for the live-load testing of historic covered timber bridges. Feasibility of the recommended protocol is also evaluated using a finite-element model analysis for a selected bridge among the tested bridges.

A 36-year-old, heavily trafficked highway asphalt pavement was analyzed in detail. The variation in structural capacity was assessed by a falling-weight deflectometer (FWD). Trenches were cut to examine the distresses in the pavement structure. Sample cores were taken for the study of distress modes, volumetric characteristics, and mechanical properties of the asphalt mixtures. Asphalt binder was extracted from the cores for the study of rheological properties. Rutting, cracking, fracture at the pavement bottom, and debonding at the interfaces were found to be the major distress modes. Air voids (AVs) were found to vary greatly in the samples and to be particularly high at the construction joints and at the pavement bottom. The total AV contents are primarily attributed to a few large voids, not a large number of seemingly disconnected voids. The stiffness of the road samples was much higher than that of the new mixture of the same type, and the average stiffness of the samples from the wheel path is lower than that of the samples from the nonwheel path. The increased stiffness by aging apparently reduces the sensitivity of the samples to stress change in fatigue tests. All binders in the different layers of the pavement were found to be severely aged, and pavement depth and mixture type significantly affect aging rate. Possible reasons for the durability of the pavement and pitfalls that may need to be avoided are discussed. The findings are important for the development of long-life flexible pavements.

Live monitoring data and simple dynamic reduced-order models of the Christchurch Women’s Hospital (CWH) help explain the performance of the base-isolation (BI) system of the hospital during the series of Canterbury earthquakes in 2011–2012. A Park-Wen-Ang hysteresis model is employed to simulate the performance of the BI system and results are compared to measured data recorded above the isolation layer and on the sixth story. Simplified single, two, and three degree-of-freedom models (SDOF, 2DOF, and 3DOF) show that the CWH structure did not behave as an isolated but as a fixed-base structure. Comparisons of accelerations and deflections between simulated and monitored data show a good match for isolation stiffness values of approximately two times of the value documented in the design specification and test protocol. Furthermore, an analysis of purely measured data revealed very little to no relative motion across the isolators for large events of moment magnitude scale ($M_w$) 5.8 and 6.0 that occurred within 3 h of each other on December 23, 2011. One of the major findings is that the BI system during the seismic events on December 23, 2011, did not yield and that the superstructure performed as a fixed-base building, indicating a need to reevaluate the analysis, design, and implementation of these structures.

This paper presents the failure of a retaining structure in special geologic conditions featuring a high level of groundwater and very thick sand layers in a metro station excavation in Nanchang, China. The retaining structures were composed of cast-in-place piles, three-axis mixing piles, and bislurry grout. Although much effort was expended in designing piles that would perform well in the specific geologic conditions, failure, including sand boils and ground collapse, still occurred. Remedial measures were taken to prevent further large failures and to maintain the stability of the strut systems. The reasons for the failure were investigated afterward by analyzing the monitoring data and conducting a series of field and laboratory tests on core samples of the three-axis mixing piles and bislurry locations. The bislurry grouting was unsuccessful in preventing seepage of ground water due to the low permeability of upper clay and silty sand, which became the main reason for the failure. Instead, high-pressure rotating-jet grouting proved to be an effective way to form a waterproof wall during excavation in these site conditions. This case provides a wealth of experience and guidance for future similar excavations with regard to mitigating this type of failure.

Different rehabilitation methods have been suggested for system improvement of existing deficient reinforced concrete building stock in seismic hazard areas. Although the use of steel plate shear walls for the rehabilitation of steel frames is common, their application to deficient reinforced concrete frames is not as common. In this study, the efficiency of steel plate shear walls on deficient reinforced concrete frames having hollow clay tile infill walls is investigated. Five one-bay, two-story $1/3$ scaled RC frames were subjected to quasistatic lateral loading. The results indicated that significant improvement may be achieved in the lateral frame response. Lateral load-carrying capacities and energy dissipation capacities were considerably increased. However, a local shear strengthening of deficient columns may be required since shear demand on the columns increases considerably owing to tension field forces of the steel plate shear walls.

After many years of service, constructed infrastructure facilities including drainage pipes, bridges, and roads show sign of deterioration. To ensure public safety and efficient management of these crucial assets, condition monitoring and mathematical predictive models have been widely used. Despite the advance in condition-monitoring techniques, closed-circuit television (CCTV) and expert-based inspection technique are still commonly used owing to their ease of use, productivity, and lower cost. Utilizing those condition data, Markov models have been widely used as a predictive tool for asset management of constructed infrastructure facilities. However, the sensitivity of the Markov model to different sampling sizes of condition data has not been investigated. This has a practical implication as more owners of infrastructure facilities start to collect condition data and are interested in understanding current and future deterioration of their infrastructure assets. This study addresses this knowledge gap with a case study of stormwater pipes. The results of the case study show that Markov models are sensitive to the sampling size of condition data. A sampling size between 600 and 700 data points is recommended for industry to collect condition data since it could provide a good starting view on deterioration patterns of stormwater pipe networks while suffering from a less than 10% error rate.