Journal of Performance of Constructed Facilities

In the first quarter of 2017, many seismic events occurred in the Çanakkale region, located on the west edge of the North Anatolian Fault Zone (NAFZ). The number of the shakings with a magnitude greater than four ($M_w>4$) was 23, and the strongest one, with a magnitude of 5.3 ($M_w$), occurred three times in this sequence. The tectonic settings and seismicity of the region are outlined briefly, and the recorded strong ground motions are analyzed. Effects of these moderate earthquakes on the regional dwellings are also studied. The earthquake-induced damages are determined after the completion of the sequence, and the observed failure and crack patterns are examined. Finally, the seismic performance of these buildings is compared to those in the Ağrı and Elazığ regions, since the same level of earthquakes hit and damaged regional buildings in these Turkish provinces in the past. In this respect, the comparison of the general characteristics of the traditional dwellings with the identified damages in different regions is the final goal of the presented study.

In this paper, safety evaluation for tunnels through steeply inclined strata in cold regions is proposed, for evaluating the safety of lining structures with existing or underlying frost heave damage. Laboratory model tests are performed to investigate the distribution characteristics of the frost heave force that acts on the lining structure, which plays an important role in the assessment of safety. The sidewall frost heave model is determined as the most fitting frost heave model in steeply inclined strata based on the available experimental data. The stress increments under frost heave can be obtained by applying the sidewall frost heave model to numerical simulations. Specifically, the maximum stress in the lining structure mainly includes two parts: the initial maximum stress under self-weight and the stress increment from the frost heave. The safety factor can be calculated through the ratio of the lining material’s strength to the maximum stress in a worst-case scenario. Finally, the practicality of the safety evaluation method is confirmed through an examination of the Balang Mountain tunnel in Southwest China.

Continuously reinforced concrete pavement (CRCP) sections contain longitudinal and transverse reinforcement that spans the entire pavement section. This paper presents the investigation result of two CRCP sections that exhibited closely spaced cluster cracks. One of the CRCP sections was in relatively poor condition because of distress in the form of several punchouts. In the forensic pavement investigation conducted jointly by a research team and the Georgia Department of Transportation, both nondestructive and destructive tests were used to investigate CRCP performance. It was concluded that the cluster-cracking mechanism was related to material and environmental factors. It was also concluded that the relatively poor CRCP section experiencing punchouts was due to poor concrete compaction and other construction issues. A long-term monitoring program was recommended by the investigation team to further identify signs of punchout distress and provide any needed rehabilitation.

Silicones have been used on a large scale as sealant materials for pavement joints. Besides the fundamental advantages of sealants, several problems remain concerning failures such as fall-down, material failure, and adhesive problems due to repeated traffic loading and the contractive or expansive issues of concrete slabs. One of the most important components of sealants is the shape factor, which is defined as the ratio of sealant thickness to concrete pavement joint width. From a field survey, fall-down failures constitute 53% of all failures, and adhesive problems constitute 33%. Based on the results of testing the vertical resistant stiffness and shape factor of sealants with 6.0- and 8.0-mm joint widths, the optimized shape factor is suggested as 1.0. The finite-element method (FEM), which was used to confirm the experimental results, supports the experimental results.

Cracking of nonbearing walls is not a problem of structural safety but is a source of nonfunctionality problems within the building. Cracking is one of the most common anomalies identified in facades during building inspections and affects the buildings’ in-service performance and durability. These inspections should be complemented with numerical modeling that can simulate the in-service cracking phenomena and help (1) improve the accuracy of the diagnosis in existing buildings, and (2) accomplish better construction practices. The objective of this work is to evaluate cracks in existing facades through inspections and then use the real conditions to validate numerical models. This work can help predict critical zones where it is more probable for cracks to appear in nonbearing walls. Moreover, it is essential to define specific constructive details for these cases and improve design projects, in-service performance, and durability of buildings.

Performance-based seismic design requires accurate damage/loss models for different seismic force resisting systems. Fragility functions are considered one of the most common damage/loss models that link specific demand parameter to the probability of exceedance of different damage states. Recently, reinforced masonry shear walls with boundary elements ($\mathrm{RMSW}+\mathrm{BEs}$) showed enhanced lateral performance and curvature ductility compared to that of rectangular walls. However, few experimental studies are available to date focusing on the seismic response of $\mathrm{RMSW}+\mathrm{BEs}$. FEMA guidelines provide fragility curves for reinforced masonry shear walls having only a rectangular cross section. Moreover, limited data are available to generate fragility curves for $\mathrm{RMSW}+\mathrm{BEs}$. In this paper, a numerical study is presented using the macromodeling approach embedded in the SeismoStruct software to simulate the in-plane lateral response of flexural dominated $\mathrm{RMSW}+\mathrm{BEs}$. The numerical model is validated against three $\mathrm{RMSW}+\mathrm{BEs}$ walls tested under quasi-static cyclic loading reported in the literature. Subsequently, a parametric study is performed on 36 $\mathrm{RMSW}+\mathrm{BEs}$ to evaluate the influence of varying the axial stress, wall aspect ratio, and vertical reinforcement ratio on the lateral response of the $\mathrm{RMSW}+\mathrm{BEs}$. It was observed that $\mathrm{RMSW}+\mathrm{BEs}$ strength increases as the aspect ratio decreases, vertical reinforcement ratio increases, and level of axial stress increases. On the other hand, decreasing the wall aspect ratio, vertical reinforcement ratio, and level of axial stress enhances the $\mathrm{RMSW}+\mathrm{BEs}$ displacement ductility. The drift ratios corresponding to three damage states (i.e., slight, moderate, and severe) were computed according to FEMA guidelines. Finally, fragility curves were generated for $\mathrm{RMSW}+\mathrm{BEs}$ utilizing the computed numerical data of the studied walls, which can be adopted in performance-based seismic design frameworks.

An open-spandrel reinforced-concrete arch bridge in west central Indiana was load posted on the basis of a simplified analytical evaluation. The posting was controlled by the shear-strength limit state of the transverse floor beams. Although transverse reinforcement was provided according to the original construction plans, there were regions that lacked shear reinforcement, which deemed these members critical. This paper presents the results of an analytical and experimental evaluation performed on one of the critical members of the bridge. The analytical models considered a spatial structural analysis of the bridge deck and a three-dimensional finite-element analysis of the entire bridge structure. Five static truck tests were also conducted to compare the measured response with those obtained analytically. The load rating of the bridge was conducted by using the live-load test results and finite-element analysis. Using simplified structural analysis does not always provide accurate load-rating results for all limit states. Moreover, the use of load testing and refined analysis demonstrated that the bridge exhibited a higher load-carrying capacity than the original posting load.

Landfill storage capacity and slope stability are among the most significant engineering concerns in municipal solid waste (MSW) landfill operation. Factors that affect the landfill storage capacity and slope stability are interrelated. Research on the effects of settlement on the landfill storage capacity and stability is insufficient. In this article, storage capacity and slope stability analysis of MSW landfills was conducted on a typical valley-type landfill. A practical approach was utilized to obtain the landfill settlement and storage capacity with the one-dimensional compression model that considered different MSW compression mechanisms and the compressibility property of MSW. The influences of settlement over time on the landfill storage capacity and stability were reflected by changing the landfill scheme and the MSW property including shear strength and bulk unit weight. The factor of safety of the deformed landfill slope was estimated by the limit-equilibrium method with consideration of varied bulk unit weight and shear strength indices for MSW with a high food waste content. The quantitative effects of operational practices, including MSW filling rate, final height of MSW body, designed front slope angle and main leachate level, on the landfill storage capacity and stability were investigated. The results showed that: (1) the main leachate level is of importance to the landfill storage capacity and stability; (2) reducing the filling rate of MSW has multiple advantages: the requirement to control the main leachate level thickness in the MSW body can be diminished, more waste can be filled, and the stability of landfills can be sustained; (3) although the landfill storage capacity can be effectively improved by increasing the height of the MSW body, at the same time, it becomes more important to control the main leachate level in the MSW body to sustain the landfill stability; and (4) reducing the slope angle will help weaken the requirement of the main leachate level to sustain the landfill stability, but not necessarily decrease the landfill expansion ratio. In addition, the landfill stability assessment should be associated with the construction stage, because the factor of safety varies with time due to the development of landfill settlement and the biodegradation process.

A new idea for model updating of masonry arch bridges is presented, which employs relative displacement of adjacent masonry blocks (RDAMB). Applicability and accuracy of the proposed method is proved by a case study. The proposed method is of specific interest for bridges with tall piers, or those located in regions with harsh environments, since it is rather difficult to record the vertical deflection of such bridges with common deflection meters. It is proposed, in such cases, to use RDAMB instead of the vertical deflection of midspans and use it for the purpose of model verification. Proposed instrumentation also offers significant cost reduction while preserving data quality. Applicability of RDAMB for calibration of the finite-element model of the bridge is also investigated and compared to common methods.

With higher requirements in stiffness and strength, the running safety of high-speed railway bridges is more sensitive to structural damage. Compared with long steel hangers, short steel hangers sustain greater damage under the action of high-speed trains. In this article, a reliable fatigue-life assessment method of short hangers was established and proposed, integrating multiple factors. These factors include bending-axial behavior, environmental corrosion, transverse location of trains, train weight, and traffic flow. As a case study, this method was applied as a reliable fatigue-life assessment of the short steel hangers of the Dashengguan high-speed railway bridge. Using mass strain data measured by structural health monitoring system (SHMS), multiorder Gaussian distributions (MGDs) were first used to obtain the probabilistic distribution of fatigue effects with multiple peaks. The Monte Carlo counting method was then used to calculate failure probability and corresponding fatigue reliability index. The influence of environmental corrosion, train weight, and traffic flow on reliable fatigue-life were finally investigated by comparing fatigue reliability index with the defined target value. Consequently, under the combined actions of environmental corrosion, increase of train weight, and traffic flow, the reliable fatigue-life may be less than 100 years, indicating that the short steel hangers of this bridge may suffer from the significant risk of fatigue cracking during the design life of the bridge.

This paper introduces thirteen kinds of typical excavation failures widely encountered in practice in China along with corresponding failure mechanisms and damages to adjacent structures and facilities. Emphasis is placed on investigation of longitudinal slip failure during excavation of subway station, which frequently occurs but rarely receives serious attention. This investigation is based on a sliding event in Hangzhou, China, in which a soft earthen slope about 13 m high inside an uncompleted subway station underwent massive slip failure. Slide debris travelling on sloped terrain caused the detachment of braced steel pipe struts and breakage of interior columns and two concrete struts atop them. Fortunately, an efficient contingency plan was executed right after the event; thus, potential catastrophic collapse of the entire earth supporting system, a domino effect of the massive sliding, was avoided. Postfailure investigations in terms of ground survey, visual inspection, and numerical analyses show that for this three-step earthen slope with an overall slope gradient (including benches) of 1 vertical (V) to 3 horizontal (H) ($1\mathrm{V}:3\mathrm{H}$), the sliding took place at the uppermost 6-m slope and there was no sign of sliding in the lower 7 m of slopes ($1\mathrm{V}:2\mathrm{H}$) atop firm to stiff clayey strata. The steep local slope gradient ($1\mathrm{V}:1.75\mathrm{H}$) of the uppermost slope overlying weak muddy clay was the predominant factor triggering the sliding; probabilistic stability analyses indicate a high slip failure probability of 88.92%. Degradation of soil strength resulting from soil deformation was mitigated by negative excess pore water pressure associated with excavation (unloading); consequently, the uppermost slope did not show signs of potential sliding during the excavation. Following postexcavation dissipation of negative excess pore water pressure accompanied by decreasing of soil shear strength, the uppermost slope underwent an abrupt sliding failure 7 days later. Apart from its recognized effectiveness in limiting lateral wall displacement, quick soil removal was helpful for keeping the soft earthen slope temporarily stable during excavation. To ensure stability of soft earthen slopes underlain by weak subgrades, a slope gradient no steeper than 1V:3H is essential. Based on sensitivity analysis results, optimal slope angles corresponding to strength parameters of soft subsoils are proposed for future excavations. To prevent slip failure of soft earthen slopes, one cost-effective solution is to install recyclable steel sheet pile vertically penetrating through a potential slide at the deepest point of the estimated critical slip surface.

When adjacent foundation pits are excavated concurrently, the stress and deformation of the soil and structures are affected by their interactions. This paper investigates the performance of two adjacent deep foundation pits in Shanghai soft clay. These pits were excavated concurrently with respective excavation depths of 15.45 and 18.50 m and 20-mm-wide confined soil in the middle zone (middle of the pits). The behavior of wall deflections in two adjacent foundation pits was examined on the basis of measured data. Results indicated that (1) greater lateral deflections and deflection rates were observed for walls in the side zone (distant from the middle of the pits) than for those in the middle zone; (2) quantitatively, the maximum lateral deflection of walls in the middle zone had an upper bound of 0.40% of the excavation depth, which was, coincidently, also the lower bound for walls in the side zone; (3) the diaphragm wall deflections decreased occasionally during the excavation, and the foundation pits tended to move toward the middle zone due to the asymmetrical earth pressure exerted on the diaphragm walls; (4) three-dimensional distribution of the wall deflections was noticed, which was primarily a result of the corner effect and the nonuniform stiffness of the supporting system; (5) the measured maximum ground settlement generally ranged between 0.05 and 0.21% of the excavation depth in the first four stages of both foundation pits, whereas in the final stage of the deeper pit, a nonlinear increment of maximum ground settlement was observed, which was closely related to wall deflection and might be attributed to the interactive behavior of the adjacent and concurrent excavations; and (6) no apparent differential heave of columns and walls was found between columns close to the middle zone and those close to the side zone.

This paper presents a field investigation that was conducted to evaluate a crack injection method. The process was proposed for sealing longitudinal cracks (LCs) that had appeared on the surface of a newly constructed highway with composite pavement. The main issue of the procedure was to restore the structural integrity of the affected areas and close the cracks to prevent water ingress into the pavement. A secondary aim was to provide a simple process that would be the most economical for repairing this kind of distress. A number of tests, such as falling weight deflectometer (FWD) and coring samples, were performed after the repair work to provide quality assurance of the injection filling of cracks. Furthermore, the repaired zones were monitored for 3 years to verify the efficiency of the sealing, and results were compared with various other treatment methods executed under the same environmental conditions. Investigation results showed practical effects improving the pavement layer stiffness, and a general profitability of the process even under traffic, without necessitating the closing of the highway. The results clearly demonstrate the effectiveness of such treatment and its competitive cost for repairing the pavement by strengthening the existing structure using injection.

The reliability of structures isolated with Triple Concave Friction Pendulum (TCFP) bearings subjected to near-field earthquakes is investigated. An extensive study is conducted to reveal the effect of superstructure mass eccentricity on the probability of failure (${\mathrm{P}}_{\mathrm{f}}$) as well as the reliability index ($\beta$) of the structure supported on TCFPs with different properties. Results of different investigations show that friction coefficient of frictional isolators depends on several parameters; therefore, it should be assumed as a random variable. In order to consider the uncertainty of earthquake records a group of 45 sets of near-fault ground motion is selected and its amplitude is scaled with a random variable calculated based upon seismic hazard curve in a specific location. The seismic performance of structures is studied through four damage states (DSs) namely slight, moderate, extensive, and complete structural damages. Two essential engineering demand parameters (EDP) (i.e., interstory drift and acceleration) are assumed as performance functions in reliability-based investigation. The First Order Reliability Method (FORM) analysis performed by Risk Tools (RT) program demonstrated that complete structural DS has lower ${\mathrm{P}}_{\mathrm{f}}$ and larger $\beta$ compared to slight or moderate DS. Additionally, 30% of mass eccentricity has reduced the $\beta$ to 23% in a six-story superstructure mounted on a 4-second-period isolator.

Multistory frame structures are generally simplified as single-story substructures to study their progressive-collapse resistance. In this study, a single-story substructure was investigated, and its behavior was applied to multistory frame analyses. However, by omitting the effect of the Vierendeel mechanism, the present simplified model could not completely reflect the mechanical behaviors of the entire structure. Based on the double-span beam model, the collapse mechanisms of the single-story substructure was investigated and a resistance calculation method for the beam and catenary mechanisms was proposed. To analyze the effect of the Vierendeel mechanism on the overall behavior of multistory frames, a top-story substructure model was established for the middle-column removal scenario, and the entire failed span was selected for corner-column removal. The contribution index of the Vierendeel mechanism against the progressive collapse was introduced. Then, a two-dimensional (2D) steel frame with four spans and four stories was considered as an example to discuss the force redistribution after middle- and corner-column removal and to verify the validity of the mechanisms mentioned. Incorporating the models, the process of demolishing four columns of the Ohio Union building was simulated. The results showed that the simplified models were reasonable. The top and bottom stories of the multistory frame showed different anticollapse mechanisms, and the Vierendeel mechanism together with other mechanisms resisted the unbalanced load. Furthermore, it was determined that the Ohio Union building has reasonable resistance to progressive collapse.

This paper discusses an experimental investigation, by centrifuge tests, of excavation behavior adjacent to existing composite foundations, with the aim to understand excavation-induced lateral earth pressures and deformation mechanisms and so assist the design of preliminary retaining structures for excavation. In particular, the behavior of excavated composite foundations was investigated based on centrifuge model tests. Experimental studies concentrated on excavation-induced lateral earth pressures, bending moments of retaining structures, lateral deformation, and ground settlement. This further led to a detailed investigation of the resulting deformation mechanism of excavated composite foundations and its influence on the safety of overlying structures and the economic design of side retaining structures. Moreover, the effects of different surcharge load amplitudes (i.e., representing overlying buildings of different heights) on the behavior of excavated composite foundations were analyzed through parametric experimental studies. Based on the experimental results, the following conclusions can be drawn: (1) excavation-induced earth pressures in the composite foundation are smaller than the Rankine active earth pressures in the depth range of the excavation, indicating that the Rankine method for predicting active earth pressure is conservative for the excavation problems in a composite foundation; (2) the excavation-induced bending moment is observed to peak at approximately 3 m below the corresponding excavation bottom; (3) the relation between excavation-induced settlement and distance from the excavation can be assumed to be exponential; (4) greater surface load induces larger lateral earth pressure amplitudes and bending moments on the retaining pile raft, whereas the position of the maximum bending moment is consistent regardless of the load amplitude.

Configuration transformation is an important issue during the construction stage of spatial suspension bridges with three-dimensional (3D) curved cables. Without fully considering this issue, the hangers could rub or interfere due to contact with the cable duct at the connection of the cable and girder, which can cause damage to the hangers and hamper the construction procedure. A novel technique using lateral bracing members (LBMs) was proposed to aid the configuration transformation during the construction stage of suspension bridges. The lateral displacement and rotation angle were investigated to ensure safety during the construction process. Limitations of the conventional configuration transformation techniques were acknowledged. To demonstrate its capability, the proposed technique was applied to a suspension bridge, the Dongtiao River Bridge, located in Huzhou, China. Based on the results, it was concluded that the LBMs can provide an efficient, reliable, and economical solution to aid configuration transformation of 3D curved cables of suspension bridges during the construction stage.

This paper is intended to provide the state-of-the-art and of-the-practice on visual inspection, monitoring, and analysis of infrastructure using unmanned aerial vehicles (UAVs). Several researchers have inspected various civil infrastructures, including bridges, buildings, and other structures, by capturing close-up images or recording videos, while operating UAVs. Various image analysis tools, such as the algorithm Morphological Link for Crack (Morpholink-C), were able to conduct precise measurements of crack thickness and length. Corrosion has also been detected using texture and color algorithms to investigate UAV-based images. Other analysis methods include structurally integrated sensors, such as digital image correlation equipment, which have helped to capture structural behaviors using UAVs. After the literature review was completed, a nationwide survey was distributed to Departments of Transportation (DOTs) to evaluate the current UAV-enabled inspection techniques that different DOTs have used or are planning to use for visual damage assessment for critical transportation infrastructures, especially bridges. Furthermore, a pertinent UAV selection was completed to indicate suitable UAVs for bridge inspection. Primary findings have shown that UAV-enabled infrastructure inspection techniques have been successfully developed to detect a broad variety of damage (including cracks and corrosions), and a few DOTs have used UAVs to inspect bridges as a more economical and versatile tool.

Buckling-restrained brace frames (BRBFs) exhibit well-controlled seismic demands due to their excellent energy dissipating capacity. However, excessive residual deformation is prone to accumulate in such framing systems after earthquakes. This poses a critical challenge to the postevent resilience and reparability. Self-centering concentrically braced frames (SCCBFs) are known for their outstanding capability to recover from large inelastic deformation. Therefore, combining SCCBFs in parallel suggests a promising strategy for BRBFs to reduce residual deformation demand. To this end, numerical studies are carried out to investigate the seismic control effect of SCCBFs for the BRBFs, particularly the influence on the residual deformation demand. This paper indicates that the BRBFs benefit remarkably from the engagement of SCCBFs by substantially reducing residual deformation. Furthermore, the combined frames exhibit residual deformation less than the out-of-plumb and reparability limits. In addition, parametric analyses of the hysteretic parameters of SCCBFs show that small values of both postyield stiffness ratio and energy-dissipation coefficient are more favorable from the perspective of control residual deformation.

As one of the largest and best-preserved Buddhist art treasure houses in the world, the Mogao Grottoes attracts a great number of tourists from all over the world. With an increasing number of visitors, the influence of visitors on the stability of network caves will increase as well. To understand the influence of tourist static load on the caves and the long-term stability of the Mogao Grottoes, the stress distribution and deformation characteristics of surrounding rock mass are analyzed under different tourist static loads using a finite-difference method. The analysis shows that these will produce a stress concentration and large vertical displacement on the cave roof and densely distributed cave area. Meanwhile, tourist load has a slight but not significant influence on the changing of the stress distribution of the caves, and the influence on the displacement is relatively obvious; however, the influence can be neglected due to its small displacement. Consequently, the effect of tourist load on the stability of the caves is not significant. However, different distribution types of tourists within the caves have an obvious effect on the distribution of displacement. Distribution of tourists on both sides of the cave should be the recommended process, mainly because it can effectively reduce the vertical displacement of the roofs and floors of the caves. Moreover, the analyzed results are of great significance to tourist management as well as to the long-term preventive protection of the Mogao Grottoes.

A four-point bending test was carried out to examine the feasibility of using cold-formed steel (CFS) channel for retrofitting of open hot rolled steel (HRS) channels. The retrofitting technique using CFS section transforms the open-channel HRS section to a closed composite (HRS–CFS) section, thereby increasing its torsional rigidity to inhibit failure due to lateral–torsional buckling (LTB). The integrity of the HRS–CFS section was ensured by adequate spot welding of the CFS section to the HRS at regular intervals along the length of the member. This technique has the advantage of accumulating minimum residual stress (spot welding) in addition to reduced manpower required for section fabrication. The test results, in general, indicate that this technique can significantly increase the load-carrying capacity (up to 60% compared to the control specimen) without deformation when local buckling of the CFS sections can be prevented by providing adequate thickness and smaller weld intervals. In addition, the test results indicate that the current specification for both HRS and CFS requires modification to adopt the same for a built-up section made of both HRS and CFS. Based on the test results, a new interconnection spacing limitation to avoid the local buckling of the CFS channel is suggested.

Across the United States, a large number of corrugated steel pipes, installed three or four decades ago, are approaching the end of their useful service life. In many cases, these aging drainage structures are having significant degrees of metal loss over their inverts due to conveyance of abrasive surface water, which can be acidic in some regions. A metal culvert under Coopermill Road near Zanesville in Muskingum County, Ohio, was selected for replacement based on its advanced level of invert metal loss. Before its replacement, invert paving was done in the half of the culvert toward its outlet end. The other half toward the inlet end was left untreated. With the concrete fully cured, each half of the culvert was instrumented with strain gauges and string potentiometers. Each half was tested under an external load of up to 267 kN (60 kip) placed over the crown. The strains and deflections were measured from the sensors, and the corresponding stresses, thrusts, and bending moments were computed. Despite the highly deteriorated conditions, the culvert structure supported a load considerably larger than the legal limit of 80 kN (18 kip). The invert-paved section of the culvert responded to the load with smaller strains, deflections, and thrusts and moments. The stresses at the interface of the steel culvert and the poured concrete treatment were not very large.

Building floor vibration can cause discomfort to the occupants or worse structural damage to the building structure. This paper presents a study on unwanted building floor vibration induced by an in-building speed bump, which was observed in a vibration root cause investigation made at a high-rise commercial building in Kuala Lumpur, Malaysia. Some of the findings of the root cause investigation are presented, which leads to the conclusion that the installed speed bump in the in-building parking lot is the main source of this unwanted floor vibration. The impact force exerted when a vehicle hits the speed bump is found to be sufficient to trigger the building resonance. The building floor vibration is explained through analysis of measured vibration signals, side car model, and finite-element analysis. It is shown that the floor vibration level depends on vehicle parameters, i.e., weight and speed, and speed bump parameters, i.e., dimensions and location. Possible vibration mitigation approaches are given.

Numerous urban infrastructures (e.g., bridges, roads, tunnels, pipes) are aging and vulnerable to external disturbance, particularly for tunneling excavation in densely built areas. A simulation-hybrid approach for protecting aging bridges against adjacent excavation-induced damages is developed. The potential safety risk of an existing bridge is assessed based on spatial neighbor relation and bridge health condition. A reasonable balance between project safety and budget constraints is reached, where the magnitude of the assessed risk is essential to the numerical analysis applied. A real tunnel project in the construction of Wuhan Metro Line 2 (WML2) in China is used to demonstrate the feasibility and applicability of the developed approach. The foundation pit of Xunlimen Station is 1.25 m away from the nearest pier of Wuhan Light Rail Line 1 (WLRL1). The impact of the foundation excavation on adjacent bridge piers is further analyzed, and relevant control measures are then proposed. The novelty of this research lies in the consideration of both hazard (spatial neighbor relation) and vulnerability (bridge health condition) characteristics for the development of responsive strategies for protecting aging bridges against excavation-induced damages.

The dynamic performance of steel railway bridges attracts intensive attention in engineering applications due to the significance and particularity of moving train actions. The monitoring of railway bridges is therefore increasingly popular because it provides a straightforward approach to help understand the train-induced dynamic responses of bridges. This study uses a set of railway bridges with an efficient structural health monitoring system (SHMS) as an example to investigate the train-induced vibrations. Accordingly, the vertical vibrations of three types of girders are analyzed with the field-measured SHMS data. Treating the bridge as a time-varying system, the modal frequencies of the structures are emphatically investigated with the wavelet-based time-frequency methodology. The transverse displacements of the piers are also presented in a time-frequency perspective to evaluate the working status. The dynamic factor due to moving train actions is analyzed and compared with the suggestions in related codes. In addition, the dynamic performance of the train during movement is also evaluated. It is hoped that the findings can provide some reference for the design and analysis of steel railway bridges.

Facility condition assessments are a key aspect of a proactive asset management approach, as they provide the information necessary to determine current conditions and work needs, as well as forecasting future conditions to identify long-range work planning requirements. While these assessments can provide a benefit to asset management decision making, they also require resources in terms of time, personnel, and funding. When these resources are finite, as they typically are in facility management, it is important to understand the value that an assessment can provide. Of particular interest to facility managers is determining the optimal time to inspect the components of a building to maximize this value. To achieve this, the paper presents a methodology to calculate the value that building component inspection information provides toward the work planning decision process. The methodology uses a value of information decision tree with a Markov component condition prediction model to calculate the probability of failure. This approach considers the time since the last inspection occurred, the expected condition state of the component, the risk consequence associated with failure, and the cost of risk mitigation related to proactive repair or replacement activities. Results of an applied case study indicate that there is indeed an optimal time since the last inspection that optimizes this value, allowing managers to better allocate scarce inspection resources using this model. In addition, varying inspection types with different levels of detail and accuracy can be analyzed, allowing for a selection of the best type of inspection to perform given the component life-cycle situation, in addition to the inspection frequency.

This article aims to deepen the knowledge in the field of landslide risk assessment by introducing a new multilevel approach to the vulnerability assessment. It focuses on an original methodology for damage assessment of either masonry or reinforced concrete ordinary buildings at the urban scale. This methodology is an essential part of Level 1 of the previously mentioned multilevel approach. It starts from filling in purposely designed forms that are completed when a damage grade is assigned to each building within the region under study according to a new damage classification. The end product of the application of the methodology is the so-called landslide damage geotechnical chart. The chart includes not only the damage grade of the buildings within the urban center investigated, but also the geomorphological and geotechnical maps of the town or area under study, and information concerning the direction of the settlements reconstructed to have caused the damage. The application of the methodology to the historical town of Bovino, in the south of Italy, is also reported.

Wind-borne debris is a major threat to the integrity of building envelope during hurricanes, tornadoes, and other high-wind events. This paper details the process and outcomes of a series of debris impact tests on different metal roof decking systems. The test assemblies were built with two deck types and two support types and impacted by wood missiles at different velocities and locations. The test protocol was consistent with the industry guidelines for safe rooms and storm shelters. Deformation of metal deck was increased with impact velocity, and impact locations farther away from support exhibited larger deformations. At lower impact velocities, assemblies with hollow steel sections (HSS) support tended to incur larger deformation than those with joist support at near-support locations but less deformation at away-from-support locations. To overcome the limitation of the experiment, future finite-element analysis studies are proposed to investigate a wider range of impact velocities and locations along with additional structural parameters of the metal roof decking system.