Journal of Performance of Constructed Facilities

Dynamic occupant action amplifies demands on structures compared to static loads and is often neglected in design. This paper focuses on 15 light-frame floor collapses caused by dynamic amplification of occupant loads, specifically rhythmic movements of jumping, dancing, and bouncing. This study investigates the increase in floor collapse cases due to occupant loadings near college campuses, their implications, and makes recommendations to reduce future collapse risk. Of the 15 cases studied herein, most failures occurred in multifamily structures within 1.6 km (1 mi) of a university in the East United States. All were determined by investigators and local building or city officials to be a result of dynamic occupancy overloads. Nine of the 15 (60%) overloaded floors were framed using metal-plate connected wood trusses. It is recommended that engineers elect to design multifamily structures in close proximity to universities above code live load minimums to counteract probable dynamic overload from gatherings.

As a new type of green material, the geopolymer has good engineering technical properties, outstanding sustainable development performance, and huge market potential. It also has significant performance advantages and economic benefits for soft soil foundation reinforcement. In this study, in order to explore the variation law of the strength of geopolymer reinforced soft soil under different geopolymer contents (the mass ratio of geopolymer to soft soil), age, and mixing time, a three-factor and three-level orthogonal test was designed, and a direct shear test and unconfined compressive strength test were carried out. It is found that the strength of geopolymer-reinforced soft soil increases with the increase of the geopolymer and with the growth of the age under the same geopolymer content. When the geopolymer content is 14%, the geopolymer has the best effect in reinforcing the soft soil. It is proven by scanning electron microscopy (SEM) and computed tomography (CT) scanning that the formation of gelatinous zeolite precursors in the stabilized soil makes the stabilized soft soil tend to have a uniform and dense microstructure. The infrared spectrum of geopolymer stabilized soil is mainly asymmetric tensile and compressive vibrations of Si-O-Si and Al-O-Si bonds and tensile vibration with an Si-O or Al-O bond. The test results of the field test section showed that the geopolymer mixing pile had a good effect, which provided a new idea for the treatment of a soft foundation.

In urban and semiurban areas of Nepal, it is a common practice that the construction of reinforced-concrete (RC) framed buildings with infill masonry have open ground floor as commercial shutter and a parking lot while the upper floor contains infill masonry for residential purposes. A reduction in a story’s infill relative to the ones above increases inelastic deformation on the columns of that story and causes soft story collapse of the open floor. In the 2015 Gorkha earthquake, the number of human casualties in RC buildings and economic loss exposed the deficiencies associated with RC. Although numerous studies have recommended solutions to soft story problems, there is still a lack of practical implementation at the ground level. In this paper, the Applied element method (AEM) was used to analyze the efficiency and applicability of existing solutions to soft story problems in Nepal using and social survey using web questionnaire to understand the social aspects of the soft story problem. Results of this research showed that, although technically there are some retrofitting methods that could solve soft story problems, the large number of existing buildings with soft stories—compounded by low awareness, unstable economic conditions, lack of locally available raw materials, and resistance to closing businesses run in the open story design—render eradicating the problem socially incapable.

Gas safety in a utility tunnel is an important scientific problem. In this study, explosion model tests of methane–air mixed gas were conducted to evaluate the safety of the gas. Furthermore, the influences of the concentration of mixed air, ignition mode, and opening area on propagation and distribution law of the blast wave were investigated. The results demonstrated that a significant explosion phenomenon existed if the methane concentration reached 10.5%, manifested by the largest explosion overpressure peak and the highest overpressure growth rate. Flame propagation was accelerated after the explosion under chemical ignition. The overpressure peak was an average of approximately 70% higher than that under the electrode ignition. The explosion overpressure and its impulse can be reduced effectively only for a certain proportion of the tunnel opening area. Therefore, the present study can provide a comprehensive understanding of the loading characteristics and the corresponding mechanism for a gas explosion in various practical tunnels.

In a southern suburb of Pittsburgh, Pennsylvania (PA), a portion of a housing development was constructed in the 1950s on an unrecognized, marginally stable prehistoric landslide mass. Grading practices of that era included placement of poorly compacted fill over a sanitary sewer behind houses on the downslope side of a street across the upslope part of the prehistoric landslide mass. A shallow landslide developed in fill and near-surface colluvium (old landslide debris). This shallow landslide was fully active by 1973 and continued to move, at least intermittently, thereafter. Landslide movements observed by a homeowner behind his house circa 2003–2004 led him to sue the Municipality, alleging that sewer leakage had caused the landslide. A detailed forensic investigation with heavy emphasis on observational engineering geology, including but not limited to historical aerial photographs and high-quality sewer inspection videotapes, clearly showed that the sewer was not leaking in the landslide area. Rather, the sewer was acting as a drain to reduce groundwater levels, thereby improving stability of the landslide.

Semimassive tanks must satisfy the requirement of watertightness, so all attempts to reduce early-age imposed strains lead to considerable financial savings. The impact of a cooling pipe system (CPS) on a reinforced concrete (RC) tank wall where early-age cracks developed during construction has been analyzed. It has been proven that for RC tanks, the factor that contributes most to tensile stresses in the semimassive walls is the mean temperature of the maturing concrete. The second most influential factor is derived from self-stresses, and the least influential factor is the stress gradient. The calculations of self-stresses indicate that the use of a CPS leads to the formation of favorable compressive rather than tensile stresses in the central part of the wall. Most importantly, a CPS in RC tank walls significantly reduces the width of cracks that result from the cumulative effect of early-age and long-term imposed strains. The performed analysis provides a basis for the effective design of a CPS in RC tank semimassive walls.

Gravity dams are important infrastructures, and their failure can affect public security. In this work, physical modeling was conducted to determine the dynamic responses and types of damage to gravity dams subjected to underwater explosions. Five tests under different impoundment levels, centrifugal accelerations, standoff distances, detonation depth, and equivalent weights were performed in a centrifuge. The mechanism of dynamic responses of the dam was analyzed. The peak strain and displacement by the shock wave and bubble pulse were both reached when the impulses of the dynamic loads were maximum. Different failure modes and degrees of damage were observed in the tests. When the explosive detonated in shallow water, a more substantial structural bending moment was generated by the shock wave to cause structural failure by bending. When the impoundment level was reduced, the dynamic responses were reduced due to the decrease in shock energy or impulse on the structure. However, new deformation or failure mode can be induced when the impoundment level is lower. Better understanding of the dynamic mechanism and proper control of the impoundment level would be helpful for dam protection.

Assessment of structural damage state immediately after earthquakes can play an important role in decreasing economic and life losses, and in optimizing decision-making for affected buildings. These advantages highlight the need for rapid, accurate, and automated structural health monitoring (SHM) methods, as well as the need for generalizable model development methods to accurately resimulate nonlinear response to find the root causes of structural damage and identify elements for retrofit. This study tracked lateral stiffness changes for a real instrumented RC building subjected to three damaging earthquakes between 2013 and 2016 using the proven hysteresis loop analysis (HLA) SHM method. An idealized trilinear force–deformation pinching model created from HLA results is proposed to resimulate highly nonlinear pinching behavior of the building under these events. The proposed model facilitates assessment of the pinching region and its characteristics in terms of seismic response, stiffness and strength degradation, and the overall seismic performance of this RC building. Average correlation coefficients between measured and resimulated interstory displacement were 0.90, 0.97, and 0.97 across all stories for the three events, respectively. Resimulated interstory displacement error was less than 4% on average over all stories and events. These good resimulation results further validated the HLA method. More importantly, the proposed model clearly showed how pinching region length and its participation in dissipating energy increases as cumulative earthquake-induced damage increases in the building, potentially helping hide significant damage from typical detection methods. Thus, in addition to presenting a generalizable nonlinear modeling approach for postevent structural assessment, the overall results bring attention to the significant role that pinching plays in seismic energy dissipation and response for RC buildings.

Most bridges in Turkey were proven to have successful seismic performance during recent earthquakes such as the Van earthquake, Mw 7.1, in 2011 and the Sivrice earthquake, Mw 6.7, in 2020. All bridges close to the epicenter of the earthquakes were still in service immediately after the catastrophic events, even though some of them were located near the vicinity of the fault line. This paper reports the performance of inspected bridges in the Sivrice earthquake zone, including the soil stability around abutments, and investigated the seismic performance of an old composite steel bridge that survived the earthquake. Field trips were conducted to the area for the postinspection of selected bridges. The geometric design of the old steel bridge was identified through classical measurement tools and point cloud models obtained from digital drone pictures in the absence of original design documents. The modern structural analysis of the old lightweight steel bridge with real-time earthquake records indicated that the bridge remained in the elastic state due to its flexibility.

Throughout the last century and in recent years, several bridge failures have taken place worldwide. Recent studies uncovered that the primary cause of these collapses was human errors in the design, construction, and operation phases. Regardless of this finding, there is still a considerable gap between this information and the known errors and the risk they represent for structural safety. Aiming for a better understanding of human errors, an identification procedure and a qualitative assessment of such errors considering risk-based indicators (probability of occurrence and consequence) was performed. Several brainstorming meetings with design and construction experts led to the identification of 49 relevant human errors, which were listed for further evaluation on a survey. Much more important than identifying and assessing these errors is identifying those that pose a greater threat to safety. Using a decision-making tool (analytical hierarchy process) to process all the information collected in the survey, the errors were ranked according to risk indicators. Furthermore, a qualitative risk assessment is performed, allowing the identification of the errors denoting higher risk for structural safety, according to experts’ opinions.

The analysis of the actual seismic behavior of the Operative Building of the Civil Protection Centre in Foligno, Italy, which is seismically isolated by means of high damping rubber bearings (HDRBs), is shown. An accelerometer network was installed on the structure. It recorded all the events of the seismic sequence that hit central Italy from August 2016 to January 2017. All the events had epicenters far from the building, so the effects at the site were quite low and the resonance frequencies measured were higher than the frequencies assumed in the design phase. The seismic filtering was effective. The strongest earthquake occurred on October 30, 2016, $\mathrm{Mw}=6.5$, with epicenter at Norcia, was studied in detail. A nonlinear law for the rubber shear modulus was deduced, which fits quite well with experimental data and was used for a nonlinear dynamic analysis of the entire building. The model was first tested analyzing the effects of the acceleration time-histories recorded during the mentioned event at the building basement. The responses obtained numerically at the sensor locations were compared with those recorded at the same locations during the quake. Then the model was used to analyze the structural response to a strong earthquake.

Extending existing performance-based initiatives, this paper provides a richer understanding of how earthquakes affect the environment and human health. Utilizing a detailed structural model, a host of emissions is predicted. Subsequently, the cost of environmental damage, such as climate change, and the cost of damage to human health, such as respiratory diseases, are calculated as a monetary value measured in dollars. A shear wall and a 6-story building serve as case studies to demonstrate the methodology and to provide quantitative insights into the effect of earthquakes on the environment and human health. The building is subjected to an earthquake ground motion, and wood, steel, and reinforced concrete options are compared for the load bearing system. The results suggest that the wood option has the lowest cost of emissions associated with repairs. The results provide a detailed account of emissions-related costs during the ground shaking and for different ground shaking intensities.

Current building evaluations, whether for occupant safety or insurance appraisal, are conducted primarily via visual inspections performed by certified individuals. These inspections, which often can number in the hundreds of thousands when performed following a disaster, can take weeks to conduct. This time can significantly affect the economic and societal resilience of a community. This paper proposes a framework for the development of unmanned aerial systems (UAS)-driven object detection algorithms for use in automating visual structural inspections. In this framework, domain-specific data augmentation methods are developed and utilized by image-based deep learning models for building inspections. A large, labeled, posthailstorm building evaluation database was developed to train and validate these models. Three data augmentation methods were developed and implemented: background cropping, high-resolution image cropping, and vent cropping. A unique combination of algorithm, novel data augmentations, and ensembling techniques was investigated to increase the performance of the framework. The results demonstrated that the framework can be applied to structural inspections to increase the efficiency and reliability of these assessments while minimizing the risk to human life.

The riveted steel truss bridge, which is commonly subjected to railway traffic loads, suffers from a potential severe threat of fatigue failure. Therefore, it is imperative to evaluate its fatigue performance. An integrated fatigue life evaluation method is proposed, and three main improvements are included: (1) fatigue evaluation is conducted with a consideration of both the stress ratio effect and load sequence effect; (2) a modified rainflow method maintaining the load sequence is introduced to consider the load sequence; and (3) a whole-range modeling methodology is applied to extend the partially known S-N curve to an S-N curve applicable to the whole range of fatigue regions, which is essential when considering the load sequence effect. To illustrate the effectiveness of the proposed method, the long-term monitoring stress data of an old riveted steel truss bridge are used in the analysis. The fatigue conditions of the monitored members are investigated, the effects of both the stress ratio and load sequence are analyzed, and a key point of fatigue life evaluation is proposed. It is shown that the longitudinal beam of the deck is the critical fatigue member among all monitored members, the stress ratio effect differs with member type and measured point, fatigue life evaluation results are obviously influenced by the effects of both the stress ratio and load sequence, and the load sequence effect is greater than that of the stress ratio effect on the fatigue life evaluation. The proposed integrated method lays a solid foundation for fatigue life evaluation of members in riveted steel truss bridges, which can provide meaningful guidance for maintenance. At the same time, sufficient attention should be devoted to the optimal sensor layout for fatigue life evaluation, which is vital for assessing a structure’s life cycle performance.

Structural health monitoring and response prediction are of great significance to ensure safety of structures and avoid structural failures. In order to capture changes of structural state in time and improve accuracy of the response prediction, a new predictive model based on dual-tree complex wavelet transform (DTCWT) combined with autoregressive moving average (ARMA) and support vector regression (SVR) is proposed. Firstly, structural monitoring signals are preprocessed and then decomposed by DTCWT. According to variable regulation of the signal characteristics at different scales, ARMA modeling and SVR training are carried out to realize prediction of each scale respectively. Finally the prediction results of each scale are fused as a final prediction model. The predictive model is applied to two case studies of quayside container cranes on the influence of different numbers of samples in prediction results. The experimental prediction results indicate that the proposed model has better prediction performance of the short-term response compared to other prediction methods, especially when the model is trained by a small number of sample data.

Building codes are mandatory documents that should be followed in all building constructions and related works. However, building code compliance requires encouraging building code users and easing the compliance process, as the building code provisions, standards, and compliance documents change over time and could presents challenges in applying the building code requirements, even though building code amendments help to improve the built environment resilience and enhance innovative techniques. This study aims to identify and explore factors that could promote and encourage building code compliance, considering regular changes in the building code, standards and compliance documents. A close-ended questionnaire survey was used for data collection for this study to measure participants’ opinions about improving and encouraging building code compliance in New Zealand. The questionnaire participants included structural engineers, project managers, geotechnical engineers, local authorities, academic/researchers, licensed building officials, building contractors, architects, and building and consulting engineers. A five-point scale was used in the questionnaire, and the obtained data were analyzed. The findings reveal that reduced bureaucracy, incentives, technical assistance, and regular monitoring and inspection without notice encourages compliance in New Zealand. Also, the study identified transparency as a primary driver of building code compliance in New Zealand. Analysis implies that there is no significant difference among the criteria used in assessing the factors that encourage and drive building code compliance. Findings in this study suggest that proactive collaboration among the relevant stakeholders could be essential to encourage a building code compliance culture and, for policymakers, to improve on inclusiveness during the building code amendment process.

The need to avoid rework or rectification, even before a facility is put into operation, cannot be overemphasized. Rework can be studied from two points of view: (1) its root causes, focusing on individual managerial issues such as worker training, coordination issues, and so forth; and (2) its distribution in the various components of the facility being constructed. Although the former has been studied quite extensively, little information is available about the latter. Addressing this gap and concentrating on building construction, this study presents the relative ranking of and the correlation among four activity-specific causes of rework, namely rework arising due to inappropriate concreting, reinforcement placement, shuttering, and scaffolding in five components of reinforced cement concrete construction in buildings, i.e., beams and slabs, columns, walls, staircases, and footings. The analysis was based on responses from more than 100 professionals and the use of statistical tools like relative importance index, the margin of error, ANOVA, Spearman’s coefficient of correlation, and structural equation modeling. It was found that whereas columns are the most critical components for rework for inappropriate concreting, beams and slabs were identified as the most critical component for rework due to inappropriate reinforcement placement, inappropriate formwork placement, and scaffolding work. Furthermore, the correlation studies exhibited poor correlation among the different building components and different activity-specific causes of rework, which implies that stakeholders need to develop activity-specific strategies for every component to reduce rework. In the future, the conclusions obtained from the study can be verified by recording and analyzing the events of rework in building construction projects.

The present paper describes the failure of an under-reamed pile foundation supporting a transmission line tower. Assessment of in-service pile conditions, i.e., in-built length, depth of bulb, uniformity of cross-sectional area, and length of the pile, are estimated through low strain integrity test. Integrity test results reveal that improper bulb formation and shorter as-built length than the designed are the leading causes of failure. Different performance criteria (uplift, compressive, and lateral capacities) of the in-service pile foundation are estimated through extensive finite element analysis and conventional approaches. Different geometric characteristics, i.e., straight shaft, different diameter of the bulb, and pile length, are simulated to represent the in-service pile conditions in the field. The estimated performance criteria are compared with the initial design values to evaluate the required degree of strengthening measures. The paper presents the initial design criteria of pile, soil condition, low strain integrity test, finite element modeling, and strengthening measures of the pile foundation to ensure the long-term stability of the transmission tower.

Pavement markings on roads and highways are used to guide the roadway users. They play an essential role in promoting efficient use of the roadway and drivers’ safety. Typically, pavement markings deteriorate at a higher rate and last between 0.5 and 3 years. Because of the short lifecycle, pavement markings require frequent inspection and maintenance. Traditionally, pavement markings have been assessed periodically by road inspectors. This manual method is time-consuming, subjective, and exposes the road inspectors to high safety risks. Therefore, this paper presents a deep learning framework for automated pavement marking defects identification. The proposed framework uses a photogrammetry data set collected from Google Maps. Images of pavement markings are processed by annotating the marking defects. A deep learning algorithm called faster region convolutional neural networks (R-CNN) has been utilized to identify the pavement marking defects. The proposed model went through three iterations of training and used 1,040 annotated images. In the final stage, the model was tested using 60 images and was run for 46,194 epochs. The model was able to identify the pavement marking defects with a confidence level ranging from 43% to 99%. The model result was validated visually by inspecting the condition of the road markings used in testing the model. The proposed automated process is capable of generating a summary report of the condition of pavement markings that can enhance the current practices.

The reliable maintenance management system of medical equipment influences the patients’ treatment and the hospitals’ performance. Although building information modeling (BIM) technology has evolved the construction industry, it does not fully comply with the facility management (FM) industry, particularly with repair and maintenance. BIM-based FM provides a structured platform to effectively capture necessary data during the construction stage for effective facility maintenance management (e.g., prioritizing maintenance work orders). Despite the design improvements and preventive maintenance plans, unplanned failures are inevitable and need quick and appropriate reactions. This paper introduces an integrated BIM-based framework for effective facility maintenance management. This framework consists of an integrated maintenance database for medical equipment, a scheduling engine to prioritize and sequence work orders, and a 4D simulation module to visualize the work-order handling process semiautomatically. Case-based reasoning (CBR) is also employed in the simulation engine to capture expert knowledge and facilitate the sequencing process. The proposed framework’s capabilities are demonstrated by applying and validating in a national healthcare facility in Iran.

The operation performance of expansion joints is crucial to the driving safety of high-speed trains and the structural integrity of long-span bridges. However, the fact that displacement in expansion joints is influenced by multiple related thermal variables in a nonlinear way poses great challenges in evaluating the performance of expansion joints. In this paper, a method originating from the least squares support vector machine (LSSVM) technique is developed to establish a temperature-displacement model and detect damage in expansion joints. The principal component analysis (PCA) is first introduced to extract inputs for the LSSVM-based temperature-displacement model with the aim of removing correlations among thermal variables. The hybrid movement firefly algorithm (HMFA), which integrates directional movement and nondirectional movement to enhance the global searching ability of the original firefly algorithm, is then proposed to optimize the parameters in the LSSVM-based temperature-displacement model and improve the model accuracy. Finally, the Pauta criterion is adopted to deduce damage thresholds from residual errors between the monitored displacement and the predicted results. The proposed method is verified by data recorded in a sophisticated structural health monitoring system deployed on the Tongling Yangtze River Bridge, which is a combined railway and highway bridge. The results demonstrate that after improvement by PCA and HMFA, the prediction accuracy of the LSSVM-based temperature-displacement model is dramatically improved. The threshold can reliably indicate damage in expansion joints.

Soakaway disposal wells are used heavily in Sudan for on-site sanitation systems. These wells have a diameter of 1.5–2.0 m, a depth ranging from 10 to 35 m, and postinstalled brick walls. They often are located close to a building foundation and seldom are excavated between footings. Although engineers are aware of induced ground movements, the influence of such movements on existing structures currently is ignored both during new excavations as well as in the structural design of new buildings. This paper studied the response of RC frame structures to settlements and horizontal movements induced by well excavation using a soil–structure interaction model. The model, adopting beam theory for the structural elements and the half-space model for the ground, uses the stiffness approach to solve the excavation–soil–structure interaction. For typical RC frames in Sudan, foundation movements caused by well excavation, additional forces in the upper frame, and resulting deformations of infill walls were addressed. As a practical suggestion, for the structural design of new structures it is recommended to use strap beams connecting pads to stiffen horizontally the foundation and, thus reduce unfavorable effects of (possible) well excavations.

Diaphragm wall structure retaining excavation of subway stations in soft soil generally involves large investments and considerable construction risks. A reasonable design is expected to provide a green life cycle solution for such structures. In this paper, the design of the existing enclosure structure of Hangzhou Metro Wenxin Station, China is examined. The analysis shows that the safety redundancy of the structure is high, but the economic performance is poor. This result is due to a lack of quantitative analysis of the degree of influence of uncertain parameters such as geotechnical parameters, construction variables, and loading parameters on the overall function of the system in design. To reduce construction risks and save materials, a multiobjective robustness design method based on correlation analysis is proposed in this study. The method is then applied to the design of a diaphragm wall retaining structure that considers safety, robustness, and economic cost, providing a reliable method for the application of smart and green life cycles in underground engineering. Because the empirical coefficient of variation (COV) of live loading parameters has significant influence on the overall performance of the system, a method based on correlation analysis is proposed to obtain an accurate COV that conforms to the actual situation and design parameters. First, considering the influence of geotechnical parameters and construction variations and the failure probability constraints of each failure mode, all feasible designs are obtained by the Monte Carlo method through comparative analysis. The Pareto frontier multiobjective optimization algorithm is introduced to find the node that reveals the balance between robustness and cost. Second, based on the obtained initial value nodes, the gray correlation degree is used to find the COV of the live loading parameter with the highest correlation degree of failure probability, and the corresponding COV is used as the calibration value to reobtain the new node with geotechnical parameters. When the COV of the live loading parameter obtained before and after the cycle is the same as that of the joint, a design parameter corresponding to the joint is the optimal design parameter, and the COV of the live loading parameter is the upper limit fluctuation threshold that the project should meet.

This paper presents a case study of local repair to damaged concrete lining in an operational tunnel, in which a local repairing countermeasure is proposed and adopted in practical implementation. The countermeasure consisted of grouting cavities with cement slurry and installing a ribbed ring reinforcement in the damaged part of the concrete lining. The field investigation and numerical analysis demonstrate the concrete lining damage is primarily induced by the field-observed construction deficiency of small-size cavities around surrounding rocks. The implemented treatment work demonstrates that the employed countermeasure is capable of local repair of the damaged concrete lining induced by the aforementioned construction deficiency of small-size cavities around surrounding rocks, which can provide the design basis for similar treatment work.