Journal of Performance of Constructed Facilities

The overturning limits of single-column pier bridges subject to overloading can be predicted using various approaches ranging in complexity from close-form formulas to detailed finite-element simulations. A simple analytical method—dubbed here analytical overturning limit analysis (AOLA)—is proposed to predict the overturning loads for single-column pier bridges. AOLA is an iterative method that determines the minimum wheel loads (position and pattern) at which an overturning state is reached. It incorporates the effects of self-weight of the bridge and the sizes and intervals of its bearings. Data collected from two collapsed bridges in China and detailed finite-element simulations of those two events are used for validating and verifying the method.

Considerable work has been carried out using a number of sensing technologies for condition assessment of civil infrastructure. Fewer efforts, however, have been directed for integrating the use of these technologies. This paper presents a newly developed method for automated condition assessment and rating of concrete bridge decks. The method integrates the use of ground-penetrating radar (GPR) and infrared thermography (IR) technologies. It utilizes a data-fusion technique to improve the accuracy of detecting defects and, accordingly, that of condition assessment. In this research, pixel-level image fusion is applied to assess bridge condition using these two technologies. GPR data are displayed as three-dimensional (3D) from 24 scans equally spaced by 0.33 m to interpret a section of a bridge deck surface in Montréal, Canada. The analysis of reflected amplitude waves is used to detect subsurface changed conditions. The GPR data are fused with infrared thermography images using a wavelet transform technique. Four scenarios based on image processing are studied and their application before and after data fusion is assessed in relation to accuracy of the employed fusion process. The concrete deck’s condition is assessed based on deteriorated areas that are extracted from the new fused image. Analysis of the results showed that bridge condition assessment can be improved with image fusion and this can enhance the capabilities of inspectors in interpretation of the results obtained.

The corrosion of reinforcement is one of the major problems affecting the durability of aging reinforced concrete (RC) structures. In this paper, the results of a study concerning the effects of reinforcement corrosion on the behavior of reinforced concrete structures subjected to the scenario of the loss of a middle column are presented. Four typical RC moment frame structures were selected as case studies. The general corrosion process induced by the penetration of chloride ions was considered for an atmospheric exposure environment that would eventually lead to the loss of reinforcement cross-sectional area, the reduction of reinforcement strength and ductility, and the spalling of concrete cover. A macro-modeling technique, which was validated by the test results and the high-fidelity finite element model, was utilized for pushdown analysis. To account for the dynamic effects associated with sudden column loss, a procedure based on energy equilibrium was employed to generate the dynamic load-displacement curves based on the static pushdown responses. The results established that aging structures with severe corrosion are much more vulnerable to progressive collapse than newly constructed ones. After 50 years of corrosion, the ultimate deformation capacity of structures was reduced by over 40%, and the first peak load capacity and ultimate load capacity of the structures were reduced by a range between 20 and 30%. Finally, linear models that depict the time-dependent changes in the load-carrying and deformation capacities of the structures to resist progressive collapse were developed with the aim of providing a simple way to incorporate corrosion effects in the design process.

The Tianjin West Railway Station, located along the Beijing-Shanghai high-speed railway, is an elevated structure and has been constructed as a novel, integrated bridge-station system. In this study, dynamic responses of this integrated train-track-railway station are computed using finite-element analysis (FEA) in conjunction with the adaptation of (analytical) system coupling techniques. In particular, a multi–rigid-body dynamics treatment of the train-track-railway system is given, based on coupling of displacements between the track and contact points of train wheels. Further, the corresponding dynamic equations of motion include considerations for nonlinear contact. Finite-element (FE) modeling of the Tianjin West Railway Station is carried out to compute modal and transient responses over a range of train passage scenarios. The analytical framework results support that (1) vibrations induced by train passages are predominately vertical; (2) vibrations are highly attenuated regardless of train passage speed; (3) such attenuation, in turn, diminishes the propensity for dynamic response of the integrated, elevated level, and roof components; and (4) the integrated structure satisfies applicable railway design-code requirements.

A collection of condition and appraisal ratings of bridges prior to collapse is presented and analyzed to show commonalities among collapsed bridges in New York State. General observations of bridge collapses are presented in addition to select consequences. Bridge inspection data are collected for the most recent inspection dates prior to the collapse of each collapsed bridge. Trends obtained from statistical analysis of existing data show 45 (46%) of collapsed bridges were structurally deficient prior to collapse, and a collapse rate of structurally deficient bridges is estimated to be $1/\mathrm{1,200}$ annually. Age and structural deficiency are shown to be related. Structural deficiency and collapse are shown to be related. Age of structure at the time of collapse is contingent on collapse cause. Deterioration-caused and overload-caused bridge collapses are age related, but hydraulic-caused and collision-caused bridge collapses have no age-determined relationship. Fifty-seven percent of hydraulic-caused bridge collapses had a scour vulnerability rating that indicated the foundations were stable for calculated scour and scour conditions. Collision-caused bridge collapses appear to be contingent on the vertical clearance: roughly 90% of bridges analyzed had a vertical clearance less than 4.5 m (14 ft 9 in.). Overload-caused bridge collapses have a relationship with the bridge being load restricted. The overload-caused collapse rate for a bridge that is load restricted is estimated to be $1/\mathrm{3,500}$ annually. Life loss is associated with 5% of bridge collapses, most of which are collision-caused. The majority of bridge collapses have low consequences related to life loss, average daily traffic, and detour length.

In 2009, a 13-story residential building founded on lightly reinforced prestressed high-strength concrete (PHC) pipe piles in Shanghai collapsed completely during the excavation of an adjacent underground garage (i.e., on the southern side). In the course of construction, excavated soil had been dumped on the northern side of the building and formed a 10-m-high fill slope before the collapse. In order to identify the principal cause of the sudden building collapse, an extensive field investigation was carried out immediately after the accident. In addition to geotechnical exploration of soil properties, physical evidence was collected and documented including the layout of collapse debris, damage to piles, and induced pile movements. To assist in the investigation and provide insights into the collapse, three-dimensional finite-element analysis was carried out to simulate the process of excavation and dumping. For piles located adjacent to the dumped soil on the northern side of the building, uppermost fractures could be seen near the interface between the reinforced and unreinforced sections, which were located approximately 1–2 m below the original level of the pile head. Most of these failure surfaces were flat, implying that these piles failed under tension. For piles situated on the excavation (southern) side of the collapsed building, the uppermost fracture surfaces were tilted at an angle and the concrete was severely damaged, suggesting that these fractures occurred mainly from compression. Photographs of the pipe interior taken with a high-resolution digital camera and results of a low-strain pile integrity test revealed that most piles examined had generally broken into three or more sections. According to results of the numerical analysis, the largest bending moment was developed in the piles on the excavation side of the building at a depth corresponding to the interface of the soft and firm-stiff clay layers (13.5 m below the ground surface), under the combined effect of excavation and dumping. This suggests that the failure occurred first for piles on the excavation side, and eventually caused the building to fall flat onto the excavation site. A lesson learned from the accident is that geotechnical engineers and contractors should be better trained to improve their understanding of the effects of surcharge loading on PHC piles. Moreover, proper construction procedures and site supervision schemes should be explicitly spelled out and strictly followed by all parties during construction.

This paper mainly presents experimental results on the mechanical behavior of corroded reinforced concrete (RC) beams strengthened with steel plates considering the influence of the corrosion rate, thickness of the steel plate, and concrete cover on the strain of concrete and steel plate, ultimate bearing capacity, and deflection. Eighteen RC rectangular beam specimens were tested under monotonic loading in the experimental program, in which nine corroded RC beam specimens were strengthened using different schemes. Three RC noncorroded beams were strengthened with a steel plate as strengthened control beams. Six RC beam specimens were unstrengthened control beams, including three noncorroded beams and three corroded beams. After loading tests, the effect of corrosion on the mechanical behavior of tensile steel reinforcement was researched. Variance analysis was carried out to quantifiably examine the effects of the thickness of concrete cover and steel plate on the indicators of the mechanical behavior of strengthened corroded beams and verify the correctness of test results. It is concluded from the statistical results of corrosion effects that the ultimate bearing capacity of the corroded beams is best associated with maximum pit depth at the failure position rather than average corrosion penetration of the rebar. The distribution of the pit location along the steel reinforcement approximately obeys a Gaussian distribution. The test results confirm that strengthening with steel plates improves the strength and ductility of corroded beams. The failure mode of the strengthened corroded beams is diagonal tension failure because of the corrosion of steel reinforcement and the critical diagonal cracking. The ultimate load of strengthened corroded beams increases from 5 to 18 kN as the thickness of steel plate increases 1 mm. The variance analysis and experimental results both showed that the thickness of the steel plate has a significant influence on the ultimate load and ultimate deflection of strengthened corroded beams, whereas concrete cover has less influence on the structural behaviors of strengthened corroded beams.

This paper intends to establish a model for the service life prediction of natural stone claddings with indirect fastening system based on a survey of the degradation state of 142 buildings in the Lisbon area. The state of degradation is evaluated through visual inspections that allow describing the extent of the cladding area affected by the different anomalies, thereby enabling the level of severity of the anomalies detected to be established. A numerical index of the degradation severity of stone claddings ($S_w$) is established; this is intended to express the global degradation level of these claddings, thus allowing the study of the evolution of their degradation with time to estimate a reference service life of this type of cladding. The results achieved in this study allow analyzing the influence of some intrinsic and extrinsic characteristics on the durability and service life of natural stone claddings with indirect fastening system. The information provided by the proposed models is essential for the definition of maintenance strategies, promoting a rational and sustainable management of the built heritage, optimizing the use of resources, and minimizing the overall cost of the building over its lifecycle.

Recycled concrete aggregate (RCA) is one of many sustainable construction materials, and its use in drainage systems by replacing virgin aggregate is beneficial from both economic and environmental perspectives. However, the use of RCA as pipe backfill material may cause a long-term performance issue such as clogging due to fine accumulation and calcite precipitation on filter fabric. Therefore, this study investigated long-term performance of RCA regarding flow rate and calcite precipitation. Long-term permeability testing was conducted to measure the reduction of flow rate with time, and the effect of filter fabric’s opening size on the flow was also evaluated. Additionally, an accelerated calcite precipitation (ACP) procedure was devised and used to estimate lifetime calcite precipitation of RCA. Two key findings are: (1) excessive RCA fine accumulation can cause significant reduction in RCA’s drainage performance; and (2) the clogging due to calcite precipitation of RCA may not be as significant as the existing and/or accumulated RCA fine.

Italian historical city centers are often composed of buildings built one adjacent to the other. This is why the present Italian technical standards introduce the concept of the building aggregate that consists of a set of adjacent buildings that is the result of an articulated and not unitary genesis owing to multiple factors. Some recent collapses highlighted the many factors that can influence the structural behavior of an aggregate even if the intervention is limited to a part of a single building. Hence, the design approach to this kind of intervention is not as obvious and simple as shown in the previous Italian standards. This paper analyzes two recent aggregate collapses that occurred in Italy to highlight not only the relevant difficulties in the forensic investigations but also the main aspects that have to be considered during the design and the site supervision of interventions in historical building aggregates.

Development of underground space in urban areas may be obstructed by the aboveground facilities that are in good condition. Instead of building new aboveground structures, an alternative solution is to add new basements under the existing structures. One of the key issues arising from this complicated technique is the behavior of the underpinning piles. This paper considers this issue in terms of a real case recently addressed in China. The retrofit construction procedure was carefully monitored. Observations included the axial-loading and excavation-unloading responses of the underpinning piles, the axial forces transmitted from the piles to the replacing pillars, and the variations in building settlement. The results indicated that the piles acted well as an underpinning role in transferring structure load into surrounding geomaterials. The mobilization degree of the pile-shaft friction increased as the shallow strata were excavated further. Abrupt increase in pillar force and building settlement were detected when the exposed portions of the piles were cut, and therefore the cutting operation should be careful for safety control. The performance-based analyses support the pile-pillar load transmission method and offer a fairly successful reference to future applications.

Two series of shaking table tests were performed to investigate the seismic performance and damping ratio of the cable tray system in nuclear power plants. The required response spectrum of compatible floor-motion time histories was generated as the input motions to the shaking table. The full cable tray (100% loading) behaved elastically in the five operating basis earthquakes, and 1.5 times of safety shutdown earthquake (1.5SSE) excitations, while buckling damage occurred at the bottom of the column in the 2.0SSE. The experimental component acceleration amplification (CAA) factor is larger than that given by current codes. To determine the relationships between the loading ratio and both damping ratio and fundamental frequency, the cable tray was excited through the shaking table with white noise that has peak accelerations ranging from 0.1 to $1.0g$. The results show that the observed damping ratios are smaller than those specified in code provisions. This study shows that shaking table tests should be conducted to define a more-reliable damping value for the cable trays in nuclear power plants. Finally, a preliminary fragility analysis was conducted using the CAA factor as the indicator.

Effects of different structural configurations, member orientations and standoff distances on blast-induced failure of steel frame buildings are investigated through development of fragility curves. Three steel frame buildings with different geometric configurations—square plan with rectangular shape in elevation, square plan with pyramidal shape in elevation, and semicircular plan with equal area at each floor level—are analyzed under blast load. The steel frame buildings are modeled, analyzed, and designed for dead load (DL), live load (LL) and seismic load (SL) for the National Capital Region (NCR), India. Force-controlled static nonlinear pushover analyses are performed to develop the fragility curves for the buildings under blast load. Different orientations of the columns (I-section) are considered to investigate the effect on building fragility under blast load. The results indicate significant effects of the structural configurations and column orientations on the blast resistance of the building. The pyramidal structure is found to be the most effective configuration in reducing the blast load effect on the structure among the considered configurations. It is also observed that the corner of a building is less critical in terms of blast load mitigation.

This paper presents a practical approach to the study of defects in a tunnel-boring machine (TBM) ring due to the lack of gap filling during the construction phases. This lack of gap fill can produce an uncontrolled ovalization of the ring, which can lead to multicracking along the segments, in particular at the tunnel crown. After a brief description of the causes of the problem and the state of the art of ovalization in a TBM ring, a real case is analyzed considering the nonlinear moment curvature behavior of a reinforced concrete section based on the constitutive laws of the materials leading to a redistribution of internal forces. The results of this approach are compared with measured field data, in particular regarding the tunnel ovalization and the crack widths detected along the ring.

The accuracy of various cable force calculation formulas is analyzed based on the vibration frequency method and difference method. The influence of cable length and diameter on cable force calculation accuracy is studied. The calculation method based on cable geometric parameters is proposed to avoid iterative calculations while still considering the impact of sag and bending rigidity. The study shows that sag and bending rigidity of the cable affect calculation accuracy: the greater the cable force, the smaller the calculation error, especially for actual cable forces greater than 5,000 kN. When considering the influence of sag, peak values, which occur if the cable length and diameter are small, arise as errors in the cable force calculated by current cable force calculation methods. When considering the influence of bending stiffness, errors in the calculated cable force are prominent: the greater the diameter, the more the error; the longer the cable, the lower the error. Whether the actual cable force is greater than 5,000 kN or not, it can be determined by string theory. The cable force calculation method based on cable length and diameter is proposed with errors of within 10%.

Remediation of a complete destroyed slope is often difficult because of various geotechnical challenges and different constraints at the site. Many solutions have been developed; however, not all stabilization methods are appropriate for every type of slope failure. In addition to the technical considerations, aesthetic concerns and sustainability have also become significant issues during the past decades because of global environmental concerns. The principle of multiple-criteria decision analysis (MCDA) will be helpful in the consideration of these alternatives when all criteria are considered simultaneously. In this study, it was concluded that compacted soil-cement would be the best solution for the site after MCDA procedures. This paper presents a detailed report to demonstrate the benefits of utilizing compacted soil-cement for the restoration of slope failure. Traditionally, compacted soil-cement stabilization has been used worldwide for embankment constructions to mitigate the constraints of problematic sites. When it is applied in a slope remediation, the stability of the reconstructed slope can be improved with the increased strength of the cemented material. The experience described herein indicates that slopes treated with compacted soil-cement not only successfully meet all the site criteria, they also display sustainable performance. Compared to slopes constructed with traditional stabilization methods, the slope in this case demonstrates superior performance. Based on field monitoring to date, the slope in the described case continues to maintain its structural stability and safety. The utilization of compacted soil-cement fill is a valuable and sustainable solution, particularly for those sites that have concerns with the disposal of impracticable silty debris waste.

The term “progressive collapse” refers to the spread of an initial local failure of a structural component in a chain of reactions leading to a partial or global collapse of the building. To design safer structures, the current research proposes the novel idea of applying concrete beams with bonded tendons to prevent progressive collapse caused by instantaneous column removal of reinforced concrete multistory moment resisting frames (MRFs). To evaluate this approach, both nonlinear static and dynamic analyses have been carried out to assess the vulnerability of 3-, 5-, and 8-story reinforced-concrete frames subjected to sudden central-column-loss scenarios at different elevation locations in the absence of tendons. Afterward, the effect of using high-strength bonded tendons in concrete beams of the stories with high potential for progressive collapse has been investigated on the load-carrying capacity of beams and structural stability enhancement. Results show that the proposed approach could be applied as an efficient procedure for progressive collapse-resistant design of reinforced concrete multistory MRFs.

The dynamic strain response due to the passing trains is one of the most important indexes in the design and maintenance of long-span steel-truss arch railway bridges. The strain influence line (IL) and dynamic load factor (DLF) are used to characterize the vehicle-induced strain response of bridge members. Temperature effects on ILs and DLFs of strain response due to high-speed trains in various bridge structural members are investigated. An adaptive finite impulse response (FIR) filter is implemented to obtain the strain IL and DLF for the response of various structural members of the Dashengguan Yangtze River Bridge using data from strain sensors that are part of the bridge structural health monitoring (SHM) system. Relationships between the strain ILs and DLFs and temperature are obtained for various members. The analysis reveals that (1) the DLFs for the short hangers require further study; (2) the effect of temperature on the ILs of each member in the subject bridge can be described by polynomials; and (3) the DLFs of the majority of the structural members are not related to temperature. Recommendations to improve the design, maintenance, and long-term monitoring of steel-truss arch bridges are provided.

The paper focuses on the analysis of the outcomes of some experimental tests carried out in San Gimignano (Siena, Italy), aimed at measuring the natural frequencies of the medieval masonry towers still present in the historic city center. Information on the investigated towers was inserted into a wider database that collected dynamic, mechanical, and geometrical features of masonry towers. A large amount of data was collected from a literature review, then summing up as many as 43 different case studies. Collected data were then used to identify the main physical parameters influencing the dynamic behavior of slender masonry towers and to critically evaluate the existing empirical formulations proposed for the estimation of the first natural frequency of such structural typology. Correlations between fundamental frequencies and the geometric characteristics and mechanical parameters are discussed, and a novel semiempirical formulation is eventually proposed for a reliable prediction of the main frequency of slender masonry towers.

In this study, in order to map storm event–induced landslide susceptibility for central Taiwan, remote-sensing data were used to interpret landslides using a geographical information system (GIS). Discriminant analysis was used to establish rules that can successfully classify landslide and nonlandslide slopes. GIS-based slope units were used as the terrain subdivision to determine landslide susceptibility. A set of causative factors and a triggering factor were used to build a landslide prediction model. Data for shallow landslides triggered by three crucial rainfall events in July 2001, July 2004, and June 2006 were selected for developing the model. Among the factors used, the total accumulated rainfall is found to be a key factor in the interpretation of landslides. The landslide susceptibility maps were built for the Guoshin region and validated using predicting samples and data from a subsequent storm event, the 2008 Sinlaku typhoon. Results show that the developed model is capable of predicting the shallow landslide distribution induced by heavy rainfall in the study area.

Explosive attacks on constructed facilities are a significant threat worldwide, producing devastating consequences including loss of life, property damages, and economic losses. This paper presents the development a blast effects assessment model (BEAM) capable of efficiently quantifying and visualizing blast effects on constructed facilities behind blast walls. The model provides novel and unique capabilities that enable designers to: (1) efficiently predict the blast damage level on facilities for a wide range of feasible design alternatives of blast charge weight, blast wall type, building material, and facility location; (2) quantify the effectiveness of feasible frangible blast wall types in reducing blast loading on facilities; and (3) generate visualizations of the anticipated facility damage areas based upon the blast charge weight, blast wall type, and building material combinations. These distinctive capabilities enable designers to accurately and efficiently evaluate all feasible design alternatives in order to select an optimal design solution that minimizes the risks to site personnel and facilities from the threat of explosive attacks.

Base isolation (BI) has proven to be an effective method to decrease the seismic vibration and mitigating seismic risks; however, construction cost of the BI buildings is expected to be increased compared with the conventional buildings due to the technology required by the BI system. Consequently, it is essential to examine if the increased construction cost of the BI system would be balanced by the reduced seismic losses throughout the life span of the building. Cost-benefit analysis can specify the economic feasibility of BI buildings with regard to conventional buildings based on loss estimation. Loss estimation procedures consider repair costs, injuries and fatalities, downtime and its consequences in seismic events; and cost-benefit analyses considering discount rates are used to assess seismic performance of isolated low-rise steel structures. It was shown that the increased construction cost of these structures can be repaid within 7–41 years. The analysis results show that seismic isolation decreases the collapse probability in superstructures significantly and can be economical in reducing seismic risk of the low-rise steel structures.

The vertical displacement of a cross section of a bridge has a close correlation with the carrying capacity and the ability to resist dynamic loads. Therefore it has been one of the most important parameters for structural health monitoring and safety assessment. Moreover, when a natural disaster such as a hurricane or an earthquake occurs, a large number of bridges will be affected. To evaluate safety performance and investigate failures preliminarily, rapid inspections of displacement are essential for bridges. This paper presents a bridge distributed displacement investigation technique using smartphones. This smartphone-based technique is a beneficial complement to conventional structural health monitoring techniques for its cost efficiency and operability. Based on photogrammetry technology, an algorithm is used to develop an app called D-Viewer. Multipoint dynamic displacement monitoring is implemented synchronously using smartphones. Experiments conducted in the laboratory with reduced-scale models show that this technique is able to monitor the distributed displacement response with reasonable precision. Through data processing, performance of bridges will be evaluated. Low cost and convenience of this technique make it possible for anyone to monitor or inspect the displacement of every short and medium span bridge preliminarily.

Formulas for tunnel crown settlement and horizontal displacement measurement are presented in this paper according to the theory of tunnel displacement as measured by a total station with three-dimensional (3D) coordinate measurement and with remote distance measurement (RDM). Comparison tests using 3D coordinate measurement, RDM, and traditional measurement (i.e., precision levels and tape extensometers) were conducted at a tunnel construction site. Tests showed that measurement of displacement by a total station is more convenient than that by traditional methods. Measurement of crown settlement by a total station with 3D coordinate measurement produces an error, which accounts for a 13% difference in total crown settlement. The accuracy of horizontal displacement measurement by a total station with 3D coordinate measurement is weak compared with RDM and traditional methods. Three-dimensional coordinate measurement is therefore not suitable for tunnel horizontal displacement. Tunnel displacement measurement by a total station with RDM obeys the law of curve and so meets the demand of construction monitoring attained by traditional methods. Use of a total station with RDM is the best method for measuring tunnel displacement, especially in tunnels with weak surrounding rock.

State agencies/provinces and civil engineers must remain current in forensic pavement investigation procedures and inspection technologies to efficiently maintain public roads. Preliminary pavement investigation procedures typically consist of visual condition surveys and subjective observations. When visual inspections indicate a functional or structural problem may exist, a more refined investigation is necessary. Nondestructive and destructive testing methods, as well as locally documented pavement performance rating data, provide valuable information to further determine the extent of a functional or structural problem. This paper presents a survey of state department of transportation practices to identify the most widely used forensic investigation techniques applied to rigid and flexible pavements. The survey results reveal that falling weight deflectometer (FWD) and ground penetrating radar (GPR) tests are the most commonly used nondestructive evaluation (NDE) techniques for forensic pavement investigation. Finally, a pilot investigation of a jointed plain concrete pavement section was conducted. It was concluded that the forensic pavement investigation procedure recommended by the National Cooperative Highway Research Program (NCHRP) 747 was consistent with the survey results and effective for implementation.

Discrete rigid blocks interacting through nonlinear elastic damageable interfaces are used to model the global behavior of a medieval masonry tower under seismic actions. The seismic vulnerability assessment is carried out by nonlinear static analysis (NSA) and incremental dynamic analysis (IDA), whose results are compared. It is confirmed that NSA results with both triangular and uniform load distributions are safety preserving and could be adopted for design scopes. In addition, the nondimensional horizontal-displacement threshold of 0.6% proposed by some building codes for existing masonry structures is aligned with NSA results and underestimates the capacity of the structure obtained by IDA. A comparison in terms of fragility curves highlights that NSA accounting for material uncertainties and IDA with record-to-record variability provide comparable levels of dispersion.

Seismic performance assessment of existing buildings requires the existing material’s properties to be determined as this has a significant influence on the seismic risk. As one of the most common construction type in Turkey, masonry buildings are assessed generally based on the recommended material properties specified in relevant codes as opposed to testing of samples taken from the existing buildings. However, due to different material types and workmanship quality, the specified properties might be quite different from the existing values. For these reasons, a comprehensive study has been undertaken to investigate the influence of mechanical properties of existing masonry buildings on their seismic performance. The study has two parts. First, the mechanical properties of materials commonly used in the Turkish masonry construction were determined by extracting wallets from existing structures and conducting laboratory experiments. The second part of the study was devoted to seismic performance assessment of selected buildings using material properties determined based on field tests and values specified in the codes. Within the context of determining existing mechanical properties, compression, diagonal tension, and shear tests were conducted on the specimens taken from existing buildings. Stress-strain responses for compression and diagonal tension tests were measured. When compared with the allowable strength values recommended by the current Turkish design code, the test results indicated significant differences from code recommended values. Thus, building assessment results were found to be greatly influenced by the material strength estimations. Based on the evaluation of material test results, lower-bound material properties are proposed for use in assessment of masonry buildings.

Dense grade asphalt concrete (DGAC), a popular surface material in Taiwan, allows for the design of the new recycling materials to reduce the use of natural aggregate. Basic oxygen-furnace (BOF) and Baosteel slag short-flow (BSSF) slag as steel byproduct are rarely used and generally disposed of. This study explores the environmental impact of replacing some of the coarse aggregates with steel slag in DGAC. Four levels of aggregate replacement (10, 20, 30, and 100%) were analyzed. Simulation results indicate that the replacement of coarse aggregate with BOF and BSSF slag increases the global warming potential (GWP) up to 7.13% compared to traditional DGAC during the production phase due to its specific gravity. However, using BOF and BSSF slag saves up to 36.41% of total cost included and reduces the environmental impact by decreasing the use of natural aggregate and the disposal of slag. Based on this result, replacement of a coarse natural aggregate with BOF and BSSF slag in DGAC is feasible and worthy of further research.

This paper presents a case study of damage in the concrete lining of an operational tunnel by field investigation and numerical analysis, in which the field-investigated construction deficiency is considered in the numerical model, and the implemented numerical analysis is adopted for investigating the effect of damaging in the structure of the operating tunnel induced by the construction deficiency. The numerical analysis illustrates that the construction deficiency of a cavity can influence the stress state of a tunnel structure and plays an important role in the stability of the operating tunnel, which results in significant influence on the damage in the concrete lining of the operating tunnel and must be timely treated to prevent subsequent damage in the tunnel lining. Moreover, the numerical model considering construction deficiency of a cavity around the tunnel is efficient for evaluating the effect of damaging the structure of the operating tunnel induced by this construction deficiency.