Journal of Performance of Constructed Facilities

This paper develops a systematic literature review to identify publications that could serve as the basis for understanding how postoccupancy evaluations (POEs) are currently being conducted. The objective is to identify the criteria that are usually assessed, the evaluation methods used, the time spent conducting the research, the types of buildings examined, and the professionals responsible for conducting the evaluations. The research was conducted using four electronic research sources covering journal and conference papers (English and Portuguese) published from 2013 to 2017. Fifty five papers that met the inclusion requirements were identified and examined according to the Who, What, When, Where, Why, and How (5W1H) tool logic, the quality tool that allows fast identification of the intrinsic elements of a project. More than half of the research used multiple assessment methods. The most used evaluation methods were questionnaires and on-site physical measurements. The most frequently evaluated criteria were lighting, internal temperature and thermal comfort, and acoustic comfort. All of the studies identified were developed by at least one researcher belonging to the academy and the time spent conducting the POEs varied according to the criteria evaluated and methods used. Finally, since there are multiple variables involved, there is no single solution for building evaluation.

A retrofit method was proposed to improve the collapse resistance of RC frame structures by installing steel cables with preset lengths on the bottom of beams. The behavior of the structures remains unchanged under conventional loads with small deformations. This leads to the elimination of inconsistency (e.g., undesired failure mode) between conventional design and progressive collapse design for RC structures. To verify this retrofit method, five ¼-scale beam–column subassemblages were statically tested under monotonic vertical loads representing an internal column–removal scenario. Experimental and analytical results found that the ultimate resistance of the retrofitted substructures improved by 90%–255% when two 10- or 14-mm diameter steel cables were used for beam–column subassemblages compared with the unretrofitted ones. In addition, preset cable lengths were determined based on deformation characteristics under conventional design and progressive collapse design. The ultimate resistance mechanism of retrofitted beam–column subassemblages was also revealed. Finally, a simplified model was proposed for the prediction of ultimate resistance of retrofitted RC beam–column subassemblages.

A confined explosion inside a critical facility may lead to the total paralysis of pertinent operations. Practical solutions to mitigate such risk include lightweight sacrificial cladding, which can be deployed as a physical barrier to protect high importance (i.e., critical) facilities from potential explosions. More specifically, sandwich panels have the potential for high energy dissipation at a relatively low cost, which makes them suitable for multiple cladding applications against a range of blast-threat scenarios. To investigate the effectiveness of sandwich panels against such threats, the results of an experimental study carried out by the authors are presented herein. The study includes 18 cold-formed steel sandwich panels featuring two core configurations selected on the basis of the resistance and modes of failure of nominally identical panels previously tested under quasistatic loading. The dynamic response of each panel configuration to the detonation of six different charges of composition C-4 at a constant standoff distance is analyzed in this paper. The test results are presented in terms of response histories, peak displacements, and observed modes of failure, while the damage levels exhibited by each panel are related to the response limits specified in design standards currently adopted in North America for the blast protection of buildings. Considerations of energy absorption and scalability suggest that panels with a unidirectional core configuration may be preferable for blast risk mitigation.

Structural deformation and damages may occur in existing tunnels because of new tunneling underneath. There is limited research on the interaction between overlying tunnels and large-diameter slurry shields in soft clay. This paper presents a case on the response of existing metro tunnels to large-diameter slurry shield underpassing in the muddy clay of Hangzhou, China. Through long-term displacement monitoring, displacement characteristics of existing tunnels during and after new tunnel construction were analyzed. Unusual tunnel heaves were observed after the passing of the shield tail because of the buoyancy effect. The existing tunnels heaved with the shape of an inverted $V$, which was well-described with the Gaussian curve. The location of maximum tunnel heave was affected by the skew angle between the new and existing tunnels. Because the overburden pressure decreased in the under-crossing area, increased maximum ground heaves were observed. The adopted countermeasures for controlling tunnel heave were introduced and analyzed. By controlling the uplift of the new tunnels, excessive tunnel heave can be prevented. Increasing the clearance between the new and existing tunnels and optimizing the grouting parameters can diminish tunnel heave effectively. Long-term tunnel settlement caused by grout and soil consolidation developed considerably after shield underpassing. Decreased tunnel settlement and increased differential settlement could be observed during the second shield undercrossing. Detailed monitoring data and analysis provided useful experience for similar projects.

Lining cracks are one of the most common distresses in in-service highway tunnels and pose severe threats to the safety of tunnel operation. Traditional methods for retrofitting distressed tunnel lining all have limitations, and the inner-surface reinforcing method using bonded steel plates is becoming increasingly popular. However, research into its use for reinforcing the distressed lining of highway tunnels is limited. This paper intends to fill this knowledge gap by presenting a case study of using bonded steel plates for strengthening the cracked lining of highway tunnels. First, the cracking status of tunnel lining was thoroughly analyzed through field investigation. It is found that water-induced swelling and softening of surrounding rock increases the overburden pressure on the structure and an aging effect accelerates the degradation of the lining concrete, finally causing the cracking of the tunnel lining. Second, the thickness, width, and spacing of bonded steel plates that have a significant effect on the reinforcing performance were studied numerically by FLAC3D software. It is found that bonded steel plates with a thickness of 8 mm, a width of 30 cm, and spacing of 20 cm can achieve optimum reinforcing performance. Finally, the field implementation scheme for reinforcing the cracked tunnel is proposed accordingly.

This paper presents an assessment study conducted to investigate the structural condition of a drainage shaft that is part of a very large aqueduct system located in the Northeastern United States. A comprehensive three-dimensional finite-element model was generated to simulate the hydrostatic uplift pressures the shaft is subjected to. The behavior of the steel shaft cover, anchor rods, other connecting elements, and the surrounding granite rock stratum are analyzed. The finite-element model covers a large cylindrical region with a radius of 32 m around the shaft centerline to a depth of 15.2 m. The rock material was modeled on the Drucker–Prager failure criterion since the von Mises criterion is not perfectly suited for modeling the yielding of a frictional material like granite rock. A condition assessment study like the one described in this paper required an extensive finite-element model created with comprehensive software like ANSYS to investigate the load and stress distribution of uplift forces through the elements of the shaft to ensure structural integrity. The special features of ANSYS SOLID185 elements are a good fit for the simulation of the nearly incompressible rock stratum of this study. SOLID185 elements with advanced capabilities such as fracture parameter calculations, stress stiffening, creep, nonlinear stabilization, and linear perturbation are used to model the rock. Since a structural condition assessment of a drainage shaft modeled with ANSYS SOLID185 finite elements have not been discussed in detail in a technical publication before, this paper fills that gap.

In recent decades, a large number of arch bridges have been built in China using a variety of construction methods. The arch-centering construction method without terrain restriction is widely used. The current research is mainly focused on the number of arch ring segments, the concrete pouring sequence, and the pouring method in arch-centering construction. However, little attention has been given to the gap of the arch centering. This paper introduces an arch centering with a span of 115 m that failed during a preloading experiment. The failure process of the arch centering is addressed and the cause is analyzed. Based on the principle of virtual work, the truss element with a gap is proposed to simulate the arch centering. The calculated result correlates well with monitoring data. The results indicate that the main cause of the failure is the inelastic deformation induced by gaps between the pin and hole of the splicing members. To eliminate the impact of gaps and maintain safety, the chords in arch centering must be kept under pressure.

Historical timber bridges are significant cultural structures and have a long tradition. There are many pre-1950s bridges still in use today. In recent years, great resources have been devoted to the restoration of historical timber bridges to preserve and pass them to the next generations. Because wood is an orthotropic, hygroscopic, and biodegradable material, structural behavior of timber bridges should be evaluated numerically using finite-element (FE) methods before and after restoration and systematic controlled in situ, or nondestructive experimental measurements should be made. This paper considers a historical timber bridge, using numerical modeling and modal testing to determine the structural modal parameters and FE model updating for approximation of numerical results to experimental results. As an application, the Buzlupınar historical timber bridge located in the Çayeli District of Rize, Turkey, is selected. The historical Buzlupınar Bridge was built in the middle of the nineteenth century, restored at different times for different reasons such as fire and wind effects, among others, and restored in 2014–2017. The FE model of Buzlupınar Bridge was formed using commercially available software to detect the initial modal parameters referenced on relief and restoration drawings. The orthotropic material properties are selected according to the laboratory material tests. Results of nondestructive experimental measurements, ambient vibration–based system identification was obtained using the enhanced frequency domain decomposition (EFDD) method (frequency domain) and stochastic subspace identification (SSI) method (time domain). The frequency values and mode shapes obtained by the FE model and experimental measurements are compared. According to these results, six natural frequencies are obtained between 2.0 and 20.0 Hz. Although the mode shapes are compatible with each other, there is a 34.55% difference between the frequency values. In order to reduce the differences, the FE model of the historical timber bridge is updated with a manual update method. Thanks to the model updating, the maximum differences are decreased to below 1% except the fourth mode. To evaluate the influence of FE model update, time-history analyses are applied, and internal forces and displacements are presented.

The Wanjiang Bridge, completed in 1976, is the first continuous prestressed concrete (PC) girder bridge erected using the incremental launching method in China. The bridge consists of prismatic separated dual box girders with an overall length of 136 m ($1+40+54+40+1\mathrm{m}$). The bridge was hit by a tanker on August 5, 2006, and three supporting brackets near Pier 5 were severely damaged. An attempt was made to repair the bridge to recover its original strength. This study evaluated the effectiveness of the repairs, the postrehabilitation properties, and the strength of the damaged brackets and the bridge using static and dynamic field load tests and finite-element method (FEM) analyses. The results show that the finite-element (FE) model and the load tests provide a comprehensive evaluation of the behavior of the bridge structure. The accuracy and reliability of the FE model was investigated and validated through a field loading test. The field loading test and the computer simulation indicated that the original performance of the Wanjiang Bridge was restored and its strength satisfies the design requirements so that any vehicle with load of less than 30 t would be allowed to cross.

Pres-Lam technology relies on unbonded post-tensioning tendons to provide moment capacity to timber beam-column, wall-foundation, or column-foundation connections. When designing buildings for high-seismic-risk areas, additional energy dissipation can be introduced by mild steel bars or replaceable damping devices. After a comprehensive testing program started in 2005, Pres-Lam technology was implemented in several buildings in New Zealand and worldwide. Although extensive information regarding test results is present in the literature, little information is available about the actual behavior of buildings in practice. This paper shows how an operative Pres-Lam structure performed as monitored over a 3-year period. Results show that the natural properties of the building are independent of the average post-tensioning loss, which was found to be equal to 5% in 3 years. Due to the natural torsional behavior of the building, the accelerations recorded were found to be around 25% higher than the spectral ones. Despite this fact, the building responded elastically to a moderate seismic event, as per design.

As the safest means of transporting gas and hazardous materials, pipelines transport invaluable petroleum material. However, a considerable number of accidents have happened involving these facilities, leading to economic losses and environmental impacts. Several inspection techniques are used to provide safety for pipelines. Despite their accuracy, these techniques are time-consuming and costly. Some failure prediction and condition assessment models were recently developed to tackle these inefficiencies. However, most of these models only predict one failure source or they rely on subjective expert surveys. This research developed three objective models based on artificial neural network (ANN) and multinominal logit (MNL) regression to predict failure sources in oil pipelines. An ANN model was developed for prediction among mechanical, corrosion, and third-party failures with an average validity percentage (AVP) of 73.7%. Another ANN model was developed for prediction between corrosion or third-party failures with an AVP of 72.8%. In addition, an MNL model was developed for prediction among mechanical, corrosion, and third-party failures with an AVP of 73.7%. Pipeline operators and decision makers can use these models to identify pipeline failure sources. They can also be applied to prioritize in-line inspection to carry out appropriate maintenance.

Socket-template steel scaffolds are supporting scaffolds that are commonly used in construction to support the gravity load of floor slabs. The buckling behavior of the overall scaffold is remarkably influenced by the complex mechanical behavior of socket connections. Inaccurate evaluation of the mechanical behavior of scaffolds has led to many collapse accidents. Thus, in this study, the mechanical behavior of the socket-template scaffold system was systematically investigated to clarify the buckling capacity of the scaffold, including the socket connections and overall system. Experiment and finite element analysis were adopted to identify the flexural behavior of socket connections and the buckling behavior of the entire scaffold system.

In this study, a hydrologic assessment approach implemented in a safety-inspection methodology for river bridges in Turkey was developed in which various hydrologic indicators such as morphometric parameters, land cover and use, precipitation magnitude and type, flood history, and presence of retention structures were selected to assess hydrologic behavior and flash-flood potential of the bridge watershed. According to the proposed approach, hydrologic grading of the watersheds was performed by summing up the grades of the indicators and classifying the bridge watershed with regard to the flash-flood susceptibility of the bridge. This hydrologic assessment approach was applied to 10 river bridges in the Western Black Sea Basin in Turkey, where bridges are often affected by severe flash floods. It was found that the selected indicators encouragingly exhibited the flood potential and hydrologic behavior of the watersheds by comparing the grades of the bridges considered. So, hydrologic assessment could enable engineers to take necessary precautions against effects of flooding on river bridges both in design and operation stages.

Water inrush disasters are the main cause of karst collapse. In this study, a physical model test was conducted to investigate the mechanism of karst collapse. The formation, expansion, and variation of a soil cave induced by water inrush were studied, including the expansion pattern of soil cavities, the voids between the bottom of the hole, cavity disengagement, wall collapse, and soil cavity expansion. The variation of shear stress in soil under the dynamic change in groundwater level was simulated and analyzed using a finite-difference method. When the groundwater level falls, the expansion and collapse of a soil cave are caused by the concentrated action of shear stress on the arch foot of the soil cave. Results of this study deepen the understanding of karst collapse induced by water inrush in underground engineering and provide guidance for the prevention and control of karst ground collapse.

In this paper, the explosion experiment of OD1422-X80mm-12 MPa natural gas pipeline was carried out to study the vibration hazards. The classic Sodev’s empirical formula was improved to predict the vibration velocity of the gas pipeline explosion. At the same time, the fast Fourier-transform (FFT) was used to analyze the data. It was found that the vibration energy was mainly distributed in the range of 0–100 Hz, and there were several subfrequency centers. The Hilbert–Huang transform (HHT) method was used to decompose the vibration into time-frequency domain. It was shown that the pipeline explosion vibration presented multiple loading modes, and there were extremely low frequency (ELF) components that existed for a long time. The research results laid the foundation for further comprehensive analysis of the hazards of natural gas pipeline explosion, and provided reference for safety design of parallel pipeline and buildings.

The trackway of a high-load gantry crane system at a shipping container logistics site in northern Israel underwent serious premature damages, which jeopardized the continued use of the system. The trackway pavement system was based on concrete paving blocks. Measurements made of the trackway surface profile and elevation profile on the surface of the uppermost granular bearing layer illustrated severe rutting and loss of paving block interlock. Considering surface and near-surface measurements, photographic and physical documentation of the materials used in the structural layering of the pavement system revealed three focal reasons for the development of damage to the trackway: improper designation of edge restraint, improper designation of bedding and joint filler sand, and excessive bedding sand thickness. The first two issues are design errors, and the third is a construction flaw. Actions taken to remedy the damages have been outlined and illustrated.

Wind turbine tower vibration parameters are critical for design and maintenance of wind farms. In this paper, measurement campaigns of two in-service 65-m tall wind turbine towers are investigated. Different field vibration measurements with contact and noncontact sensors, including integrated circuits piezoelectric accelerometers, passive servovelocimeters, a laser Doppler vibrometer, and an interferometric radar, were conducted in the campaigns. Frequencies, damping ratios, and mode shapes were identified based on the measurements by use of a stochastic subspace identification method. Performances of the contact and noncontact sensors were compared in time and frequency domains. Also, time-frequency spectra were used to figure out noncontact measurement sections with high quality. Because the superior frequency ranges of contact and noncontact sensors are different, a data fusion method, which can take advantage of both types of sensors, was introduced. The practicality of field vibration measurements for modal parameter identification is discussed, and the results are compared with those from simplified finite-element models of the tested wind turbine towers.

Deformation control and stability analysis are very important for tunnel construction. Large deformations of the constructed primary support accompanied by lining cracking and spalling occurred in the Dongxishan Tunnel located in Chaozhou City, northeastern Guangdong Province, China, posing a serious damage to the tunnel safety. In order to determine the causes of large deformations, comprehensive investigations have been performed by combining field monitoring, laboratory tests, and mechanism analyses. The results show that there have been three main factors resulting in the occurrence of large deformations in the Dongxishan Tunnel: the plastic flow of surrounding rock due to low strength of silty clay, obvious creep behavior, and water-weakening effect of silty clay. Besides, based on the preceding mechanism analyses of large deformations, many countermeasures were proposed during construction, including double row pipe pregrouting reinforcement, strengthening primary support, and timely closing of temporary support. These countermeasures can effectively deal with large deformation problems in the Dongxishan Tunnel from the in situ feedbacks. This paper can provide useful guidance for avoiding the similar anomalies in the following excavation and support of Dongxishan Tunnel.

Bridge building entails considerable risk, as attested to by the relatively frequent occurrence of worksite accidents. In the accident reported on here, an overhead gantry derailed during the construction of the last of 13 spans on one of two nominally identical parallel bridges composing a precast concrete girder viaduct. As no prior anomalies had been detected, the structure was the object of a detailed forensic inquiry. The most likely hazard scenario was inferred from the mutually reinforcing findings gleaned from numerical calculations, experimentation, eyewitness accounts, and reconstruction of the accident sequence. Organizational flaws such as less-than-optimal interfacing and data exchange among the actors involved in viaduct construction were observed to be among the major underlying causes. The study showed that effective quality-assurance strategies, fluent worksite actor intercommunication, and a clear definition of tasks and responsibilities are of cardinal importance in preventing accidents.

Bridge vehicle-load and damage-condition information plays a vital role in the structural analysis and assessment of bridges. This information can be derived from bridge responses (such as displacement, acceleration, and strains). Most existing bridge damage and load identification methods are based on different measurements from both the bridge damage and load subsystems (different sensors and methods) in the literature. Accordingly, more sensors and measuring activities are required; therefore, the costs associated with structural health monitoring tend to rise. This paper proposes a new method for the synchronous identification of damage and vehicle loads on simply supported bridges, which uses just one set of long-gauge fiber Bragg grating (FBG) sensors and reduces the use of sensing devices, sensors, and costs. In the proposed method, the correlations among the peak values of static macrostrain curves, bending stiffness of bridge cross sections, and vehicle loads are established based on the macrostrain influence line theory. A numerical case study of a 30-m simply supported bridge, subject to moving vehicles, is performed to preliminarily validate the effectiveness of the proposed method. In this case, the damage identification error is below 6%, and the load identification error is less than 4%. In addition, a laboratory experiment including a model bridge and car is conducted to further examine the feasibility of this method in engineering practice, and the results show that the model bridge damage and load can be identified synchronously with good accuracies.

Insulator fatigue, lighting strike, or flashover could result in the breakage of insulator strings. Insulator breakage can cause conductor impingement on the ground, which is a threat to the safe operation of a transmission line. To study the influence of this accident on the dynamic responses of a tower-line system, this paper proposes a method to simulate the impingement between the ground and a conductor, and then a finite element model (FEM) of a transmission tower-line system with four towers and five-span lines is established. Several cases are simulated to investigate the impingement between the conductor and the ground and its effect on the dynamic responses of the tower-line system after insulator breakage. The results show that the impingement decreases the vibration of the tower-line system. The traditional methods, neglecting the impingement between the conductor and the ground, overestimate the response of the structure, and the results thus do not accord with the actual situation. Therefore, it is necessary to consider the effect of the impingement between the conductor and the ground surface to better estimate the dynamic response of the tower-line system.

Remote construction sites, such as oil production facilities and military forward operating bases, are frequently targeted by explosive terrorist attacks. These attacks produce devastating and far-reaching consequences that can be grouped into four main categories: personnel loss, psychological impact, economic loss, and operational impact. Existing security models rely on time-consuming external blast analysis software packages to quantify the consequences of explosive attacks and therefore cannot be used to optimize the layout planning of remote construction sites. This paper developed a novel facility layout optimization model capable of directly quantifying blast consequences and generating optimal site layout plans and protection strategies. The model is implemented using multiobjective genetic algorithms to identify solutions that provide optimal tradeoffs between the competing objectives of minimizing site explosive attack consequences and minimizing site construction costs. A case study of a hypothetical remote military base was analyzed to demonstrate the use of the model and display its unique capabilities.

Concrete water tanks have a stringent serviceability requirement in terms of limiting crack widths. Excessive cracks or cracks running across the full depth of these tanks could result in loss of serviceability from leakage and affect their integrity. This scenario is particularly true for liquid retaining structures, such as water tanks. In this paper, following a field inspection that revealed considerable cracking in the walls of a water tank constructed in the arid Arabian Gulf environment, a diagnostic investigation was carried out on the water tank, which was $30\times 20\mathrm{m}$ in plan and 3.6 m in height. Field inspection and assessment, laboratory investigation, and a three-dimensional (3D) finite element simulation of the water tank structure was carried out to investigate the causes of the cracking. A repair strategy was implemented, and its performance was assessed. The heat of hydration characteristics of the concrete mix used was obtained using a semi adiabatic calorimeter. The heat of hydration, free shrinkage strain, mechanical properties of the concrete, and the ambient conditions at the time of construction were used in a three-dimensional (3D) finite element simulation model. Tensile stresses resulting from restrained temperature and shrinkage strains exceeded the tensile stress capacity, resulting in cracks in the tank walls. A repair strategy was proposed and implemented to restore the functionality of the tank. Based on the diagnostic methodology proposed in this paper, guidelines have been suggested that address the mitigation of the risk of cracking attributable to thermal and shrinkage stresses in the harsh and arid environment in the Arabian Gulf.

In recent years, overturning accidents of box girder bridges have occurred frequently, causing widespread concern among researchers. From the perspective of bridge structure monitoring, this paper presents two technical routes for evaluating the risk of potential overturning risk of a bridge: (1) traffic loads monitoring based on an anti-overturning stability coefficient and (2) structural response monitoring based on the control of a bearing’s rotational angle. For the second route, a simple and feasible monitoring scheme is presented depending on the structural response—displacement of measured points on both sides of bearings. Then, a method to assess bridge anti-overturning reliability is proposed. The influence of aging of rubber material on the rotation performance of a bearing is further considered. Finally, the study applied the method described above to an anti-overturning analysis of the Northeast Ramp Bridge at Tongji Road in Shanghai, which demonstrated the method’s feasibility and effectiveness.

Columns are the main load-bearing structure elements in frame structures and outermost columns are the critical structural elements for potential extremist attacks. The explicit nonlinear finite-element method (FEM)–based computer program LS-DYNA is used in this paper to study the response of reinforced concrete (RC) columns subjected to blast loading. The sole objective of this paper is to quantitatively investigate the effect of geometry on the RC columns under a variability of blast loading. An extensive parametric analysis is executed numerically on different shapes of columns to understand the influence of scaled distance, reinforcement ratio, and seismic detailing, after verifying the model with experimental and numerical studies. The responses reveal that the reinforcement ratio, seismic detailing, and scaled distance have a great influence on the blast performance of RC columns with various cross sections. Using the RapidMiner tool, a linear regression analysis is carried out to investigate the most influential parameter.

The Yellow River Dongming Highway Bridge (YRDMHB) is a prestressed concrete rigid frame-continuous girder bridge located in Shandong Province, China, constructed in 1993. After 10 years of operation, a deflection of 150 mm was observed at the midspan of the bridge, and this deflection had a considerable negative influence on the serviceability of the structure. This research presents a strengthening process for the YRDMHB using stay cables to mitigate the midspan deflection. Specifically, the girder structure is modified to a pseudo-cable–stayed bridge by adding an extension system, which consists of two pairs of stay cables, towers, and joist-bracket structures. Furthermore, steel joist-bracket structures are added below the four sections of the main girder to anchor the cables. The load of the girder is shared by the cables and transferred to the new main towers, changing the internal force and line shape of the girder. Through this strengthening method, the original girder structure is upgraded to a cable-girder cooperative work system. The strengthening work includes theoretical analysis, laboratory tests, plan implementation, and field load tests. First, the strengthening scheme using stay cables is illustrated and laboratory static load tests are conducted to verify the applicability of the proposed plan. Second, the strengthening scheme is implemented and the key mechanical and geometrical parameters are monitored. Third, to examine the effectiveness of the strengthening project, field load tests are conducted. The results show that the static and dynamic performance of different span box girders is better than that before strengthening. Through the strengthening process described in this paper, the stiffness of the structure is improved by strengthening.

The United States has more than 615,000 bridges. US national bridge inspection standards developed by the Federal Highway Administration (FHWA) require routine inspections of these bridges every 24 months regardless of bridge characteristics such as age, average daily traffic (ADT), and current deterioration condition of a bridge. Previous studies reported that this routine inspection process is considerably costly and inefficient. If the future condition of a bridge can be predicted accurately, costly routine inspections with uniform intervals can be avoided. The objective of this study is to create a forecasting model that predicts future bridge deterioration conditions based on the bridge characteristics. Historical data of more than 28,000 bridges in the state of Ohio from 1992 to 2017 were used to create an ordinal regression model to statistically examine effects of bridge characteristics on variations in bridge condition and predict future bridge conditions. The outcomes of this study indicate that bridge characteristics such as age, ADT, deck area, structural material, deck material, structure system, maximum length of span, and current condition of the bridge are statistically significant variables that explain variations in bridge deterioration. The results of the forecasting process show that the created ordinal regression model can statistically predict future bridge conditions precisely. This study will help bridge owners and transportation agencies accurately model and predict bridge deterioration and assign inspection and maintenance resources efficiently. The efficient inspection process, customized based on predicted deterioration condition, can result in investing the millions of dollars currently funding unnecessary inspections into much-needed infrastructure development projects.

Shallow and asymmetrically loaded tunnels are very common in mountain tunnel portals, and localized excessive deformation, cracking, or even collapse often occur during the construction process. In this study, a shallow and asymmetrically loaded tunnel entrance is used as an example to discuss the primary support failure mechanism by means of field observations and monitoring and three-dimensional (3D) numerical simulation. Asymmetrical loading, rainfall, and mismanagement were the three main triggers of failure events. The continuous rainfall infiltration significantly reduced the quality of the surrounding rock, resulting in an increase in the initially high asymmetrical loading. The retaining wall and surrounding rock failed to provide sufficient counterpressure on the shallowly buried side, leading to large deformation of the primary support at the beginning of excavation. The deformation increased continuously and quickly exceeded the allowable value; however, the project was not stopped in time, and further excavation occurred due to a communication failure between the monitoring and construction crews. Thus, severe damage to the primary support occurred when the tunnel face reached a distance of 24 m from the entrance. To avoid more hazardous damage, a temporary support mainly composed of 20b I-steel was installed immediately to prevent deformation; 30 days later, a cutting slope was created on the deeply buried side to reduce the asymmetrical loading, and the excavated rock mass was stacked at the shallow buried side to increase the counterpressure. Then, the temporary support was removed, and a secondary lining was applied in a timely fashion. The monitoring data showed that good results had been achieved. This study provides useful recommendations for the construction safety of shallow and asymmetrically loaded tunnel portals.

Expansion joints of bridge superstructures generally suffer deterioration more severely than their main structures, and their actual service life is generally shorter than their design service life. This paper aims at evaluating the wear condition of slide bearings in expansion joints for long-span suspension bridges under monitored traffic flow in the operation stage. The spring element was introduced to model the expansion joint and verified by field load tests. The vehicle−bridge dynamic analysis on a steel truss girder bridge was realized in a nonlinear analysis system, in which the monitored traffic flow was simulated to investigate the back-and-forth displacements of expansion joints. Finally, the wear condition of slide bearings was evaluated by comparing cumulative displacements with the critical value specified by the wear criterion. Findings from this research led to the development of an approximate formula to estimate the cumulative displacement at the expansion joint for long-span suspension bridges, suitable for hand calculations.

This study investigates the performance and design of an aluminum honeycomb panel attached to the face of a steel column for reducing local damage caused by vehicle collision. The dynamic plateau stress of the honeycomb panel is obtained from impact analyses and is used for design of the panel to mitigate vehicle impact. To verify the impact energy-absorption capability of the honeycomb panel designed with the proposed method, a vehicle collision analysis is carried out using a finite-element model of an 8-t truck. According to the finite-element analysis results, the honeycomb panel can be effective in decreasing the damage of the column by absorbing part of the impact energy. Based on the analysis results it is concluded that the proposed design method reflecting the dynamic characteristics of the honeycomb panel can be useful for preliminary design of protective system for columns.

Highway and bridge agencies use several systematic inspection approaches to ensure an acceptable standard for their assets in terms of safety, convenience, and economic value. The Bridge Condition Index (BCI), used by the Ontario Ministry of Transportation, is defined as the weighted condition of all bridge elements to determine the rehabilitation priority for the bridge. Therefore, accurate forecasting of BCI is essential for bridge rehabilitation budgeting and planning. The large amount of data available about bridge conditions for several years enables the use of different mathematical models to predict future BCI. This research focuses on investigating different classification models developed to predict the BCI in the province of Ontario, Canada, based on the publicly available historical data for 2,802 bridges over a period of more than 10 years. Predictive models used in this study include k-nearest neighbors (k-NN), decision trees (DTs), linear regression (LR), artificial neural networks (ANN), and deep learning neural networks (DLN). These models are compared and statistically validated via cross validation and paired $\mathrm{t}$-test. The decision tree model showed acceptable predictive results (within 0.25% mean relative error) when predicting the future BCI and is the recommended option based on its performance and certainty in posterior maintenance decision making for the selected case study.

Several experimental and analytical studies have evaluated the seismic response of reinforced masonry (RM) shear walls either as a component (i.e., planar rectangular walls) or as a system (i.e., building consisting planar walls). In the current study, five RM flanged walls were assessed for their seismic performance and collapse capacity. The impact of utilizing flanged walls was assessed and characterized through recent available guidelines. In this respect, a 2-D fiber-based modeling approach has been developed using the Open System for Earthquake Engineering Simulation software. The results indicate that the selected RM flanged walls can satisfy the acceptable criteria proposed by the methodology. The seismic resilience of the archetypes against the expected collapse risk was evaluated in terms of functionality curves before and after the use of the flanges in the walls. Damage levels were considered as performance level functions correlated to earthquake intensity and were used to estimate total loss and recovery time of the archetypes. The selected RM flanged walls showed enhanced earthquake resilience and less damage than rectangular RM shear walls.

The purpose of this paper was to report a rectification method that was used for plumbing a tilted transmission tower supported by a shallow foundation over a soft clay layer. The restoration method involves the installation of the grouted micropiles at the perimeter of the foundation. Hydraulic jacks resting on the top of micropiles and steel brackets attached to the existing foundation were used to lift the tilted transmission tower. The micropile construction processes, as well as the rectification data, are reported and analyzed in this study. The outcomes of the rectification case history highlight the effectiveness of the postgrouting technique for the micropile, because it was able to increase the axial compressive bearing capacity of the micropile almost 2.5 times compared with the nongrouted steel-pipe micropile, based on the pilot pile load test results. The increase in compressive bearing capacity of the micropile was crucial to guarantee the safety and serviceability requirements of the rectified transmission tower.

The investigation concentrates on the most predominant cause of bridge collapse (239 or 55%), which is the result of hydraulic effects. Out of all the causes of bridge collapses, the National Bridge Inventory (NBI) and constructed control groups found that hydraulic collapse diverges significantly. The control group consists of randomly selected bridges from the 2017 NBI, controlling for age and other parameters. The study of hydraulic-collapsed bridges yields statistical trends through nonparametric tests. Results for hydraulic collapse include an annual failure rate of approximately 1 out of 8,500. Structural deficiency is associated with hydraulic collapse at a rate of 44% in comparison to the control group, which has a rate of 15%. Precollapse evaluations for hydraulic-collapsed bridges and the control group are scour critical at a rate of 17% and 6% and scour stable at 83% and 94%, respectively, when nonscour-evaluated bridges are omitted. Precollapse substructure condition rating is poor for 34% of bridges and is lower, or 11%, for the control group. The substructure condition rating is a better indicator of collapse than the scour critical appraisal rating; additionally, scour is paired with less hazardous conditions (e.g., minor cracking with minor scour). Consequences are limited for hydraulic collapses compared to other causes of collapse in terms of average daily traffic traversing the structure and life loss. Maintenance issues are presented to reduce hydraulic bridge collapse with consideration for underwater inspections and flood events.

The current study aims at evaluating the causes of premature failure of roads in India by field investigation along with suggesting remedial measures to mitigate the earlier deterioration with a cost-effective analytical approach. From the initial field investigation near the Satara District, the results show that the major failure of low-volume roads (LVRs) is mainly due to the heavy and overloaded vehicles which take the LVRs running parallel to the highways to avoid fee collection booths. In addition, the data related to the average annual rainfall, annual temperature, groundwater patterns, and soil patterns reported from the field investigation shows the diversities in natural and weather conditions that are the major cause of premature failure of LVRs. Along with field investigation, a two-dimensional finite element analysis is performed after authenticating the methodology with the reported case history to obtain the pavement response on critical parameters for variation in thickness and material properties of various constituent layers. The calculated results are then included as inputs to calculate the fatigue and rutting lives in terms of number of standard axles. The scope of work is extended to find the unknown nodal values along the decisive factors such as temperature, seepage pressures at various points, and gradients with the application of analytical tools. The results show that the weather changes and the natural parameters along with the overloading conditions are the major causes of premature failure of LVRs in India. Thus, to mitigate the earlier deterioration, it is suggested to have separate designs at various locations after finding the uncalculated nodal values along with the decisive factors such as temperature, seepage pressures at various points, and gradients with the application of the analytical tool.

Ground penetrating radar (GPR) has emerged during the last decade as a nondestructive testing method for assessing the subsurface condition of infrastructure components. However, the use of step frequency ground penetrating radar (SF-GPR) antenna arrays has been limited due to the significant complexity of postprocessing data analysis. One objective of this study was to investigate how SF-GPR can provide the necessary input for assessing the bridge deck condition at both project and network levels so as to be used in routine condition assessment of about 3,000 bridge decks distributed along the state of Maryland. For being able to do so, key bridge deck condition parameters were identified and selected with bridge engineers at the Maryland state highway authority responsible for bridge inspection monitoring. This paper presents the proposed methodology for monitoring and reporting such key condition assessment parameters (including concrete surface condition, concrete cover, deck thickness, top rebar condition, and surface elevation). Results from two bridge deck structures are presented herein as an example to demonstrate the use of the suggested methodology and analysis. Furthermore, fuzzy sets analysis was introduced in order to compare the conditions of different deck spans of the same bridge or between different bridges. The use of SF-GPR increased data collection speed and improved bridge deck condition assessment in relation to traditional methods (such as coring, chain drag, and chloride concentration) and reduced condition assessment monitoring cost because the GPR surveys are faster to perform and may require minimal traffic control in relation to the data collection speed. The proposed methodology has been successfully used for monitoring the bridge deck conditions of several hundred bridges in Maryland, and thus it can be adapted and implemented elsewhere where SF-GPR surveys may be considered for bridge deck condition assessment.

Developing an appropriate and efficient inspection pattern for an unknown bridge substructure is a critical issue for bridge engineers, contractors, and bridge agencies. This paper introduces a two-phase near-surface inspection strategy to determine the foundation depth of fully submerged pile bents of an existing bridge. Electrical resistivity tomography inspection provided the overall interface between bridge substructure and surrounding soft soils. Ultraseismic inspection provided more information to determine the depth of the substructure. Time-lapse waveform image analysis and frequency analysis of ultraseismic inspection results also displayed varying degrees of reliability for estimating the pile bent length, which was positively confirmed with the bridge design charts. The entire set of investigations demonstrated strong conclusiveness in determining the foundation depths when the results from these two testing methods were corroborated with appropriate analysis modes.

Traditional interface design integration for a mass rapid transit (MRT) project focuses on the integration needs of specified interface requirements among civil and electrical and mechanical (E&M) subsystems. This approach does not differentiate in terms of how to fit all physical interfaces of the chosen E&M specifications into designated civil designs without preassessing engineering necessities upon subsystems’ interdependencies. When designs are completed, all engineering interfaces are embedded and require time and resources to manage during construction. This study aims to propose a series of interface design criteria for guiding the latest MRT project design, which is adapting a driverless automation train control system. By performing a thorough review of previous MRT construction interface issues including failure experiences, the types of recurrent interface dependencies for generalizing reusable interface design criteria are identified systematically. Two design-build (DB) MRT cases have been used to demonstrate the preventive interface design approach and its benefits. The findings of this research contribute to the engineering interface management body of knowledge for showing great potential in saving construction time and resources for future DB MRT projects.