Journal of Performance of Constructed Facilities

The Mireuksaji stone pagoda (the only remaining building in Mireuksaji temple) has existed for 1400 years. More than half of the Mireuksaji stone pagoda has collapsed. Due to the historical, cultural, and architectural value of the Mireuksaji stone pagoda, which reflects the style of wooden buildings of that era, it is necessary to evaluate and investigate the cause of collapse for reconstruction and restoration plans and the structural stability of this cultural heritage. For this reason, in the first step, material properties of stones in the pagoda were investigated by taking samples from some of the separated stones that originally constituted the pagoda. Uniaxial and triaxial compressive strength tests, tensile strength tests, and nondestructive tests for the porosity and absorption rate of the stone were carried out. In the next step, three-dimensional numerical analysis software for discontinuous modeling based on the distinct-element method was used to model and analyze the pagoda as accurately as possible. Because the interface between stone blocks is a critical part of the main load-bearing system in the discontinuous structure, some sensitivity analysis was done to consider the effects of structural performance. The analysis also considered different imperfections due to weathering deterioration (material degradation) and irregular shape of remaining stones (surfaces are partially in contact) and their interfaces.

Bridge scour is a phenomenon that describes the loss of riverbed sediments around bridge supports because of flow, and it has been identified as one of the leading causes of bridge failures. The aim of this study is to investigate the performance of existing methods for estimation and mitigation of local scour using calculated and measured results. The present comparison between design methods in the United States and China show their own characteristics and deficiencies. The influence of pier width and sediment parameters on scour development was first analyzed. The predictive equation widely used in the United States and the design standards used in China were compared. In total, 796 data records collected from field projects were used to evaluate the accuracy and behavior of scour estimation models. The performance of these scour estimation methods are discussed regarding different ranges of parameters separately. Existing models used in design standards in the United States and China are found to perform unsatisfactorily, especially for large piers or piers with a small or large ratio of pier width to particle size. Under such conditions, the equations by these standards tend to significantly overestimate the scour depth. However, an appropriately designed countermeasure can provide reliable protection. Both scour estimation and mitigation are important to avoid bridge failures in practice. Case studies on Sutong Bridge and Houfeng Bridge in China have been carried out to highlight these key strategies for bridge design, construction, and long-term service.

The horizontal rotation angle (HRA) exceeding the design limit can result in the failure of a rail fastening system and irregularity of the track geometry state. In the traditional view, the temperature field in a steel truss is usually considered as uniform, but some monitoring results have shown that a steel truss bridge can contain remarkable temperature gradients, which may have a significant effect on horizontal rotation. The influence of temperature gradients on HRA at the beam end of a steel truss bridge was thoroughly studied. A monitoring data analysis was carried out to identify which types of temperature gradients contain remarkable values in the steel truss; a correlation analysis was carried out to reveal which types of temperature gradients have a dominant influence on HRA; and a reliability analysis was carried out to determine whether the HRA in the real environment can exceed the design limit in the entire lifetime. The results show that HRA is dominantly affected by the transverse temperature gradient between the bottom chords and the transverse temperature gradient between the top chords in the side trusses. The reliability estimation result shows that the HRA in the real environment will not exceed the design limit during its entire lifetime.

Shield tunnel damage induced by excessive and differential tunnel displacement has become a major threat to the operational safety of urban subways in China. Grouting offers an effective way to reduce excessive displacement and ensure structural safety of the damaged shield tunnels. In this paper, a case study on the remediation of an operational shield tunnel in Shenzhen, China, by grouting is presented. The drop of the groundwater level caused by nearby foundation excavation was the main reason for tunnel damage. Grouting outside the tunnel was selected considering the site conditions and construction time limitations. An automatic monitoring system for tunnel displacement was installed. The monitored data showed that parameters including the relative tunnel displacement, the horizontal convergence, and the ovality were all reduced after grouting, indicating that the tunnel serviceability was improved. The deformation of the shield tunnel induced by grouting was composed of translation and shape change. The tunnel displacement remained stable when the foundation excavation was resumed. Careful design and real-time adjustment of grouting parameters are key to the successful implementation of the grouting project.

This paper presents a numerical investigation of the reliability and applicability of modeling strategies used to perform progressive collapse analysis of RC structures. Three widely adopted numerical approaches based on displacement-based element (DBE), force-based element (FBE), and macro joint element (MJE) are comprehensively studied. The formulations and characteristics of each strategy are first introduced, and the adopted material constitutive models are then presented and set as the same in different approaches. Some benchmark experiments of RC beam-to-column subassemblages that are subjected to column removal are selected as the reference to validate the three modeling approaches. Finally, influences of several typical modeling parameters in different strategies (e.g., mesh size for the DBE, integration points for the FBE, and bond-slip effect for the MJE) are studied, and some recommendations for a practical numerical modeling procedure are made for progressive collapse analysis of RC structures.

A large number of soft-first-story reinforced concrete (RC) buildings have been significantly damaged or completely collapsed in past earthquakes. In this paper, the seismic performance of a nonductile soft-first-story RC building retrofitted with eccentrically steel-braced frames was evaluated. At first, the results of the previous experimental investigations on the RC frame retrofitted by the steel-braced frame were used to calibrate the analytical results obtained by the open system for earthquake engineering simulation software. The modeling of the flexural behavior of the RC and steel members were accomplished by the well-known fiber model technique. Moreover, the shear and axial failures of the RC members were taken into account. Secondly, the intended building was planned to be retrofitted by five retrofit strategies. Four retrofit strategies are strength type, and one retrofit strategy is strength–ductility type upgrading. Nonlinear static and dynamic analyses were implemented to evaluate the seismic performance of the nonductile soft-first-story building and the retrofitted ones. The results showed that, in the strength-type retrofit, because of lack of required ductility, premature shear and/or axial failures of RC columns are more likely to occur than those failures in nonretrofitted ones. Also, it was found that the variation of the axial and shear forces in the boundary RC columns and the slenderness ratios of the steel braces are the critical factors influencing the seismic responses of the buildings retrofitted using the steel-braced frames.

Partial mining, including room-and-pillar mining and strip pillar mining, is a widely accepted method for mining coal because it can effectively control ground subsidence and reduce damage to surface structures. Because coal mines can be in mountainous area, terrain profile can have a significant effect on the stress distribution in the mine roof–pillar–floor system. This paper reports an investigation of the terrestrial effect using numerical simulation. The results showed that the horizontal stress concentration at positions beneath the slope bottom [defined as bottom abrupt stress (BAS)] is influenced by the slope angle and the depth of mine. The BAS value can vary significantly compared with the maximum horizontal stress for a lateral ground surface, and the BAS is responsible for the mine roof instability in mountainous areas. The results were validated by comparison with a physical model and field measurements.

A three-dimensional (3D) numerical model was developed in this paper to investigate the damage and failure of a concrete gravity dam under attack from a noncontact underwater explosion based on experiments performed in centrifuge. The effects of shock waves and bubble oscillation were considered based on a multistage histogram of pressure. The damage and failure of a concrete dam were represented by a rate-dependent damage-plasticity model. Systematic numerical simulations and a parametric study were performed considering different cases of explosive charges, standoff distances, and explosive depths. By adopting the shock factor, the explosive charge and the standoff distance were condensed into one governing factor, and an empirical formula was proposed to estimate the damage of the concrete dam under attack from an underwater explosion.

This study focuses on the internal shaft friction of open-ended tubular piles induced by jointed weak rock plugs. To investigate the bearing mechanism of the plug, push-up load tests were carried out on the jointed mudstone inside a tubular pile. The discrete-element method (DEM) was used in order to consider heterogeneity and to reproduce the discrete nature of the rock mass. A flat-joint model was used to reproduce the mechanical behavior of mudstone, and a smooth-joint contact model was used to replicate natural joints. The push-up load tests were carried out using the calibrated properties of a weak mudstone. The effects of joint density and joint dip were examined in detail and, as expected, the push-up force of the rock plug was influenced by the joint properties because joint density and joint dip had to some extent affected the plug resistance. The existing joints reduced the push-up force when the joints were steep, whereas the horizontal joints had a minimal effect on altering the inner shaft friction compared with the intact rock mass. The reduced friction along the pile was amplified with joint density, while the exponential increase of vertical stress from the top of the rock plug to the bottom revealed that the inner shaft resistance was mainly mobilized at the bottom portion of the rock plug. The findings of this study increase our understanding of joint dip and joint density affecting the internal shaft resistance of open-ended tubular piles; this knowledge can be used further to develop a design methodology for open-ended tubular piles in weak rock while assessing plugging effects.

Although research has shown the potential for integrating building information modeling (BIM) and facility management systems (FMS) and has indicated the importance of using efficient maintenance strategies to reduce facility maintenance management (FMM) costs, there is a paucity of literature that assesses facility risk and strategic actions based on the prioritization of equipment maintenance at the component level. To bridge this gap, this paper developed a facility risk assessment and maintenance system prototype that will enable facility managers to select the maintenance policy for a single piece of equipment and determine the maintenance priorities of equipment components in the initial stage of operation and maintenance (O&M). The maintenance policy was selected by using the analytic hierarchy process (AHP), and facility risk assessment based on fuzzy multiple-criteria decision-making (MCDM) was performed to determine the maintenance priorities of equipment components. In this way, the failure modes of the equipment components and the risk order can be analyzed to support facility maintenance decision-making. A facility maintenance system that has embedded policy and maintenance decisions was then developed. Disruptive technologies, such as BIM and augmented reality (AR), were applied to guide the maintenance processes. Finally, a case study demonstrated system implementation.

This study investigates the effects of using building information modeling (BIM) and construction operations building information exchange (COBie) data for facility management (FM) over multiple campuses of the Health Science Center (HSC) buildings of a large university. While research conducted in the past to determine the impact of using BIM for FM was based on interviews and surveys, this study utilizes actual data exported from the computerized maintenance management system (CMMS) used by the HSC. Work orders in BIM user and non-BIM user campuses were processed and compared with a two-sample $t$-test. The results of the statistical analysis contradict the findings of earlier studies that work order processing time may be reduced by using BIM for FM. In fact, a lack of standard rules for recording work order data across all campuses within an organization is a hindrance to validating the effects of using BIM and COBie data for FM. Research has yet to show a clear value for using BIM and COBie data for work order processing times, and this paper may help FM professionals and researchers understand the aspects involved.

This research identifies the most common failures in the indoor elements of buildings (e.g., partition walls, flooring, tiling, renders). A total of 18 types of damage, 29 types of causes, and 88 types of pathological processes were identified as repeatedly occurring in construction in Spain and leading to user complaints. Four zones were differentiated by 593 incidents (cases): partition elements, acoustic insulation, indoor cladding, and flooring. The most frequent types of damage were bulging or tenting of floor tiles (111), fallen parts (80), lack of acoustic insulation (76), vertical cracks (65), cracks in finished elements (56), and humidity/runoffs in finished elements (50). The most frequent causes were lack of adherence (108), faulty acoustic insulation (72), deficient connection of brick wall with other elements (70), and inadequate characteristics of material or finishing. The results obtained will allow designers and developers to minimize failures.

The distress history of a geogrid-reinforced segmental retaining wall (GR-SRW) that was constructed as a highway shoulder, June 2014, using loess backfill in Shaanxi Province, China, is presented. A narrow, arc-shaped pavement crack propagating toward the wall and a vertical open gap between the cover plate and coping were found in September 2014. Improper diagnosis and treatment caused the crack and gap to worsen until June 2016. Consultation, field observations, measurement, drilling, laboratory tests, and internal stability analyses were executed immediately to determine the causes of the distress. Consultation and field observation were executed to obtain the GR-SRW development on November 5th, 2018. The insufficient and differential compaction of the loess backfill likely caused the distress initially found. Water infiltration, fine-grained loess backfill use, and improper diagnosis and treatment worsened the GR-SRW distress from June 2014 to November 2018. Preliminary repair suggestions, including a prestressed anchoring wallboard retaining wall, upswept drainpipes, rammed soil-cement or compacted soil-lime columns, and rebuilding the existing pavement layers, were provided. Lessons learned provide a reference for future construction.

The structural temperatures and thermal effects on the cable forces of a long-span cable-stayed bridge with prestressed concrete girders were monitored. The temperatures were distributed as a three-segment polyline through the depth of the girder on hot sunny days, in which temperatures on the top surface and bottom surface were 15.4°C and 10.3°C higher than those on the webs, respectively. The monitored temperature distribution was quite different from the specification in the current Chinese design code, resulting in adverse load effects, especially on hot sunny days. Some cables were predicted to have remarkable thermal effects on internal forces, such as those near the side piers, in the center of the side span and near the towers, which were verified by field measurements. Therefore, special attention should be paid to these cables in the design and maintenance of the bridges on hot sunny days. Based on the monitoring of structural temperatures, the variations in cable forces induced by temperature were separated from those induced by traffic loads, which was helpful in safety evaluations of such bridges.

Various issues can cause quality defects or local damage to a dam body that pose a serious threat to the stability of the dam and its operational safety. Displacement, stress, and other mechanical responses in a traditional finite-element method cannot reflect the actual impact of reinforcement measures on the stability of dam bodies. Based on deformation reinforcement theory (DRT), a reinforcement and effect evaluation method for defective arch dams is proposed. The effect of reinforcement on the overall stability of arch dams is evaluated by plastic complementary energy (PCE) norms, and the amelioration of the local stresses of a dam body is evaluated using the unbalanced forces. This method was applied to Dayakou Arch Dam, which needs reinforcement owing to construction defects, and a reinforcement scheme for setting up a concrete body in a dam abutment notch is proposed. The reinforcement mechanism and reinforcement effect are studied and analyzed. An optimization of the reinforcement scheme is further proposed based on the analysis. Numerical calculations demonstrate that the proposed reinforcement schemes have significant effects on improvements in the overall stability of the defective arch dam and have the advantage of simplicity and friendliness to concrete construction. The actual operation of the reinforced Dayakou Arch Dam proves the suitability of the proposed reinforcement measure.

Model tests were conducted for sand foundations reinforced by geocells, waste tire chips, and geocell–tire chips. Three factors related to the foundation performance are mainly examined in the current study: the embedded depth of the first layer of the geocells, the vertical spacing of geocell layers, and the content of waste tire chips. The experimental results indicate that, for a geocell-reinforced foundation, the optimal value of the vertical spacing and embedding depth is 0.2 time the footing width. The bearing capacity of the tire chips-reinforced foundation increases with the tire chips content when this content is within 8% and then decreases as the content of the tire chips increases. The optimal content of the tire chips is found to be approximately 8% by weight of the sand mixture. The performance of the geocell–tire chips composite reinforcement is superior to that of the reinforcement with only geocells. The vertical and lateral displacements of the composite-reinforced foundation are reduced remarkably and distributed more evenly. For instance, the vertical displacement under 2.5 MPa load is only 16 mm. The earth pressure of the composite foundation is significantly reduced as well. The discrepancy in the stress of the sand foundation and the reinforced foundation will be less obvious as the foundation depth increases. The diffusion effect of the reinforcement materials on the stress is mainly distributed in the vicinity of the reinforcement, with little influence on the part far away from the reinforcement materials.

Infill and partition walls as nonstructural elements are generally constructed with hollow brick masonry and briquette as single or multilayered vertical walls. The seismic responses of infill walls and reinforced concrete (RC) framed buildings have been investigated with field observations after earthquakes all over the world. This study focuses on the reasons infill and partition walls failed as a result of the October 23, 2011 ($M_w=7.2$), and November 9, 2011 ($M_w=5.7$), Van earthquakes in Turkey. In this paper, in-plane, out-of-plane, and combined failure mechanisms of single and multilayered infill walls enclosed within reinforced concrete structures were investigated, and construction rules were suggested. To limit the failure of nonstructural elements enclosed within an RC frame, design and construction requirements should be included in the seismic code by adopting suitable solutions for both in-plane and out-of-plane behavior. This paper will be a reference for future studies that investigate infill wall damage.

Maritime works deteriorate continuously and at a certain moment in time are in need of some sort of repair. Usually the decision maker seeks technical advice and has to consider the resources available. A literature review showed great limitations in the tools that are today in use. This paper presents the implementation of a decision support methodology to prioritize repairs in rubble-mound breakwaters using MACBETH. Models for the benefits of repairing breakwaters, which are based on visual inspection data only, were created, and an expert meeting was held—the decision conference—following MACBETH. As outputs, the criteria, the value functions, and the weights to obtain scores were generated. Yet, using the condition indices set for the different levels of analysis of the breakwater, the decision maker will decide whether and how to intervene. The analysis uses MACBETH for calculating the scores and considers the benefits of the interventions in the armor layer for a breakwater divided into reaches. Costs and benefits are used afterward to prioritize the interventions. The common issue of the limited budget available is solved by applying portfolio—set of interventions—creation methods. The Ericeira rubble-mound breakwater (Portugal), which shows some signs of deterioration, was selected as a case study to illustrate the methodology. Interesting enough, the use of this new methodology shows what are the reaches that must be repaired in the very first place, which was not evident when using conventional analysis. The breakwater head gets the largest benefits in being repaired.

This paper presents an outside strengthening method of existing frame structures with a precast bolt-connected steel plate–reinforced concrete (PBSPC) frame-brace. The working principle and advantages of the PBSPC frame-brace are introduced. To verify the retrofitting effectiveness of the upgrade system, quasi-static tests were conducted for three groups. The results showed that the peak load reached almost 3.6 times that of the nonstrengthening conditions, accompanied by larger initial stiffness and smaller lateral displacement. Numerical simulation models that showed ideal accuracy with the test results were presented based on Open System for Earthquake Engineering Simulation (OpenSees) software. Furthermore, parametric analysis was performed to demonstrate the optimization factors of the proposed upgrade technology, including, for example, brace height, steel plate size, and brace position. The proposed method plays a significant role in system-level upgrading and provides references for future studies due to assembly convenience.

Arch dams appear vulnerable to underwater-explosion (UNDEX) shock loadings due to their relatively thin bodies. Many seismic analyses have highlighted the significant nonlinear joint contact behavior in dynamic responses of arch dams. This paper examines the effects of the transverse contraction and control joints, particularly the combination of the two joint types, on the UNDEX-resistant performance of arch dams. The investigation takes the form of a numerical case study of a 141-m-high arch dam subjected to an UNDEX using ABAQUS/Explicit. A surface-interaction-based approach that can consider damage initiation, evolution, and ultimate failure of the shear keys was employed for the joint modeling. The results show that the shear keys undergo considerable shearing damage under a 50-kg trinitrotoluene-equivalent UNDEX, which is mainly distributed at the upper halves of the joint interfaces. The radial displacement of and tensile damage to the dam in the basic case are not strictly enveloped by those in the two extreme cases. The damage-preventing effect of the control-joint implementation seems somewhat less pronounced than expected. This study has identified the significant role of transverse joints in UNDEX-induced responses of arch dams. Extreme approaches to the joint modeling in arch dams do not necessarily produce extreme results for the UNDEX-resistant performance evaluation. The control-joint implementation should be reviewed on a case-by-case basis in design practices. The surface-interaction-based approach could probably be usefully and easily employed in engineering practices.