Journal of Performance of Constructed Facilities

The excavation of underground pipelines in Taiwan has led to widespread complaints and, in some cases, claims for national compensation. This issue has also caused significant challenges for road authorities, directly impacting the citizens’ satisfaction with the government’s policy of the so-called Smooth Roads Project. This study interviewed executives from road authorities, pipeline agencies, and engineering consulting companies to obtain a thorough understanding of current underground pipeline management, public utility databases, and common duct policies in Taiwan. In addition, building information modeling (BIM) is currently applied mostly to buildings, rarely to road infrastructure. Therefore, in this study, BIM was used as a basis for developing the concept of road information modeling (RIM). According to the interview surveys, respondents generally agreed that RIM would be tremendously beneficial to underground pipeline management. This study examined frameworks and strategies for the promotion of RIM from policy, legal, technical, implementation, and application viewpoints and developed an implementable example of RIM. This study presents a significant contribution to underground pipeline management, and its findings provide a basis for improvements in road maintenance and management.

In this paper, a system failure probability method, considering principal failure modes of the soil-nailing retaining structure and random factors of the system, is put forward. Taking the excavation of the east public square of the Jinan high-speed railway station as the case, the paper first defines principal failure modes of the soil-nailing system according to its working mechanism and collapsing characters. The failure probability of each mode and then the system failure probability were calculated by considering random factors of the retaining structure. The soil nailing–supported excavation was proved to be stable and some effective construction measures were put forward based on the failure probability result during the construction period. A numerical simulation was carried out to analyze the stability of the excavation during each construction step. By using a strength reduction method, safety factors of the excavation were determined. Displacement and shear stress of the excavation were within allowed limits during every calculation step. At the same time, vertical and horizontal displacement of the top point of excavation, horizontal displacement of different depths, and the force of the soil nails were monitored during the construction period. The monitoring data were reasonable and consistent with the results of theory and numerical calculation.

A case was examined in which an underwater shield tunnel was rehabilitated during the construction phase. An unexpected methane eruption resulted in an inrush of water and silt, which damaged the tunnel. Because of this situation, the sleeve method was adopted to repair the tunnel and to mitigate the environmental influence. The process and technologies for rehabilitation are explained in this work. The finite-element approach was also used to simulate the repair procedure and to analyze the risks in the construction phases to ensure the safety of the tunnel. This presentation of rehabilitation in key construction phases can serve as instructions for similar engineering accidents that occur in the future.

The paper presents testing of the detrimental effects of water and frost on asphalt pavements. It included laboratory testing of fatigue life of asphalt concrete that was subjected to action of water and frost and field testing of damages caused by water and frost on existing asphalt pavements, such as stripping, raveling, and potholes. Laboratory simulation of water and frost action was based on the original AASHTO T283 method and its modification. The original method was modified in such a way that instead of a single freeze-thaw cycle, 50 and 150 cycles were applied. Fatigue life was measured in the indirect tensile fatigue test in the Nottingham Asphalt Tester (NAT) apparatus. The asphalt concrete specimens were prepared in laboratory. Some specimens contained liquid adhesive agent—namely, fatty amine—and others did not. The detrimental effect of water and frost was clearly identified. Also, the results of field investigation—condition survey of existing pavements and the results of laboratory tests on water and frost resistance of samples cored from the these pavements—were presented. The testing procedure, the results, and the practical conclusions are presented.

The primary objective of this research is to study the relationship between surface movement and hydrological triggers of a large and active landslide in the Three Gorges Reservoir (the Shuping landslide). When the landslide was reactivated in June 2003 owing to the impoundment of the Three Gorges Dam, measurement of surface movement began through the use of manual global positioning system (GPS) monitoring. Since June 2012, near-real-time data with fine temporal resolution have been collected through the use of continuous automatic GPS. In total, more than 10 years of surface movement have been recorded for the Shuping landslide. Patterns of surface movement have been spatially identified first, and then subsequently over time. A fast moving zone can be spatially identified from the primary deformation zone. The temporal evolution of the landslide consists of a typical stepwise progression in time with short periods of fast movement (FM) and longer periods of slower movement. Eight of the former have been identified. The hydrological conditions and triggering factors can be understood by performing detailed correlations between displacements and daily fluctuations of reservoir water levels and rainfall records. The results indicate that any continuous rapid drawdown of the reservoir water level from approximately 160 to 145 m will definitely trigger FM. Generally, there is a lag time of approximately 6 days after the water level is reduced. In addition, there is a definite correlation between fast velocity and the rate of drawdown. Meanwhile, prolonged and periodic intense rainfalls have a slightly relevant effect on the movement of this landslide. This shows that long-term and near-real-time monitoring are invaluable for the understanding of landslide movements and their hydrological triggers.

A soft ground arresting system (SGAS) is an alternative solution on airport runways where the runway safety area (RSA) does not meet international Federal Aviation Administration (FAA) standards. If an SGAS is installed on both ends of the runway, the length of the runway can be shortened. In this paper the options of using foamed concrete as the arresting bed material in an SGAS are investigated. Tests were conducted on the foamed concrete to determine whether it has the ability to withstand support vehicle loadings, while failing underneath loading from an overrunning aircraft. The objective of this paper is to present the required and measured properties of foamed concrete and results of an evaluation into its possible implementation as an SGAS as an alternative to engineered material arresting system (EMAS) on airports. The following conclusions are drawn. Foamed concrete properties allow it to be used as a possible arresting material, with the unit weight/density of foamed concrete the most important property to consider. The compressive strength and energy absorption of foamed concrete are two of the major properties allowing it to be used as an arresting material. Foamed concrete with densities of 600 and $800\mathrm{kg}/{\mathrm{m}}^3$ allowed for more settlement while the stress/deformation relationship was very similar to that of material currently used in arrestor beds. The large contact diameters of airport rescue firefighting (ARFF) vehicles’ tires allows them not to penetrate/destruct foamed concrete at densities as low as $600\mathrm{kg}/{\mathrm{m}}^3$.

This paper discusses advances in evaluation, health monitoring, and rehabilitation of cable-stayed bridges, and available methods. In the last 2 decades, the writer has contributed extensively to advances in cable-stayed bridge construction, design, and health monitoring. Information gathered from evaluation of the strength and reliability of dozens of stay cable systems worldwide, and health monitoring and inspection of more than 12 cable-stayed bridges in the United States and abroad, have discovered problem conditions that seem to be consistent across many types of cable-stayed bridges and stay cable designs, and have helped toward formation and evolvement of a unified approach for in-service evaluation and problem solving of these aesthetic structures. A case study related to evaluation and rehabilitation of the Luling Bridge in Louisiana, for which the new approach has been implemented almost entirely, is also described. The bridge evaluation process, and cable replacement design and its implementation, contain unique aspects and are the first attempted in North America. The cable replacement design accommodated an extraordinary construction sequence to address constraints on space and traffic flow. Temporary cables minimized stress variation and allowed for the live load without restriction. The new cable system allows individual strand installation and tensioning, and is expected to facilitate future inspections and replacement.

For a fast treatment of winter distresses, a 1-cm-thick rollable pavement was developed based on a textile-reinforced concrete with short fibers. After the rollable pavement has been placed, its surface is treated with epoxy resin and chippings ranging in size from 2 to 5 mm are applied. This ensures an adequate skid resistance and low tire-surface noise. The research presented in this paper also includes results of performance tests. Firstly, the tensile strength of the rollable pavement was determined using the four-point bending test and compared with the actual stresses in real road pavements. Then, the specimens of the rollable pavement were polished using the Aachener ravelling tester. Changes in the texture and their influences on the acoustic properties, the skid resistance, the drainage, and the ravelling were studied and optimized where needed. It can be concluded that this innovative rollable pavement has high mechanical resistance and stability and very positive texture characteristics. With this technique, winter distresses can be repaired within only a few hours. The new road surface can be opened for traffic quickly after the repairs are made. Therefore, this technique has the potential to contribute to durable road structures and sustainability in road engineering.

Recycling of poor soil becomes very important when good-quality construction materials are limited. This paper investigates the properties of lightweight treated soil such as strength properties based on the stress-strain behaviors, durability by simulating the freeze-thaw cycle (FTC), and evaluation of the road performance when lightweight treated soil was used as a subbase layer. Lightweight treated soil was made by mixing dredged soil waste, cement, air-foam, and water with the determined proportion. Test specimens were prepared with various cement contents and air-foam contents. Several series of unconfined compression tests, FTC tests, and thermal conductivity tests were then conducted. From the results of the experiments, it is observed that the strength of lightweight treated soil increased with an increase in cement content, but decreased with an increase in air-foam content or number of FTCs. The thermal conductivity of lightweight treated soil decreases with increasing air-foam content. The resilient modulus of lightweight treated soil was determined from a repeated load triaxial test to predict the fatigue and rutting life of a road. Based on the pavement performance life, recycled dredged soil using the air-foam stabilization method could be used as a sustainable pavement material.

Red clay is a common roadbed filler in China. In southern China, because of the high natural moisture content, it is hard to make enough compact clay in the process of roadbed filling construction, and it shrinks and cracks when dehydrated. This article compares the domestic regional soil properties of red clay in China, analyzing its physical properties, composition, chemical properties, and water characteristics, and the filler used in the construction of the Dongxin expressway. Swelling of the red clay packing was also observed. According to laboratory tests, field test analyses, and settlement observation tests, when using red clay as road filler, the use of a smooth bump grinding wheel and rolling of subgrade compaction works best for controlling moisture content, with the wet compaction test method within the range of $\pm 5\%$ of optimum moisture content. This method can ensure the strength and stability of the subgrade to provide guidance for the use of red clay in construction.

Heavy rainfall-induced landslides along mountain routes in Taiwan easily cause road interruption, especially under extreme rainfall conditions. Road interruption due to rainfall-induced landslides is a major problem for Taiwanese authorities. In this study, remote sensing data, including satellite images and aerial photos, were employed to interpret landslides, which were mapped using geographical information systems (GISs). The goal was an event-based landslide inventory. Causative and triggering factors for landslides were adopted in a logistic model to predict landslide occurrence. These factors included lithology, normalized difference vegetation index, slope gradient, slope roughness, maximum elevation, total curvature, total slope height, maximum hourly rainfall, and total accumulated rainfall. With the proposed landslide prediction model, the probability of road interruption due to rainfall-induced landslides was evaluated under different rainfall-return periods. The model was confirmed by careful validation of reported historical events involving road interruption caused by subsequent typhoons. Validation results indicated that the landslide prediction model can be used in predicting road interruption due to rainfall-induced landslides.

Potential risk assessment and early-warning system are essentially important to ensure the safety of high-speed railway (HSR) bridges. This paper presents an in-depth methodology of this risk assessment and early warning. Firstly, the risk sources, occurrence probabilities, and hazard consequences were investigated by consulting specialists. For kernel-risk sources, such as excavation and dewater activities, finite-element models were established to evaluate the deformation of foundations and approach embankments in various conditions. Then, with combined quantitative and qualitative analysis, the as low as reasonably possible (ALARP) criterion was utilized to obtain the results of risk assessment. On the early-warning system, autoregressive integrated moving average (ARIMA) method was used to predict the continuous deformation and to analyze the kernel indices that may affect the railway operations. At last, the forewarning interval of each index that can be used in the construction monitoring was suggested. The proposed methods of risk assessment, settlement prediction, construction monitoring, and early-warning system have been successfully applied to the Cuiheng Road Underpass of the Beijing-Tianjin Intercity Railway and may be used in future similar projects. Practices have shown that these methods can effectively reduce risks, ensure structural safety, and maintain sustainable development.

The application of carbon fiber-reinforced polymer (CFRP) layers on existing hollow clay tile infill walls with proper anchorage has already been established as an alternative seismic rehabilitation method for reinforced concrete frames. This method has been investigated considering some major aspects during the last decade. Yet, the possible effects of some other parameters should be addressed. A numerical model which had been generated for reinforced concrete frames strengthened with the proposed methodology and verified by the experimental results was utilized for such a study. The parameters that are considered in this study are the flexural rigidities of beams and columns, infill wall thickness, width of the CFRP fabrics, and aspect ratio of infill walls. The change in the global frame response attained by CFRP strengthening with respect to each parameter is indicated. The results emphasize that there is a considerable effect from infill wall thickness and diagonal CFRP width on the overall enhancement provided by the applied strengthening. In addition, there seems to be a correlation between these two parameters. As a result of regression analysis of the results, the relationships between lateral load capacity/initial stiffness enhancements, infill wall thickness, and CFRP width are derived.

To estimate the impact of Hurricane Ike of 2008 on local communities, service areas of hospitals and corresponding service populations were calculated at both the county and facility levels within the Houston metropolitan statistical area. A hospital access indicator was defined to measure the level of access to medical services when compared to the prestorm level. The result indicated that the hospital access indicator reached its lowest value on the next day after the hurricane landfall due to lane closures and hospital shutdowns before showing a steady comeback. However, the recovery was briefly interrupted around September 18, 2008, as a result of road closures to remove debris on State Highway 146. Access to hospitals nearly returned to the prestorm level by the end of October 2008. Simulations were then performed to identify priorities for repairing damaged roads in order to minimize storm’s adverse impact. This paper offered a simplified method to measure, monitor, and analyze the effect of transportation network on access to healthcare facilities in the aftermath of a hurricane. Since only a small number of publicly available variables were required, the method could be applied to other catastrophic events in support of disaster response and recovery decisions.

Over the lifetime of a bridge, traffic loads cause numerous stress-strain cycles within its components which in turn lead to the slow accumulation of damage in them. The rate of progression of this damage with time is affected by several human-induced and natural factors such as volume and type of traffic loads, environmental conditions, and maintenance practices. Traffic volume and truck weights have been steadily increasing with the growth and technical development of the freight industry. With increased truck weight limits being anticipated in the future, a detailed study of the potential detrimental effects of such increases, especially due to overweight trucks, on the durability of bridges has become necessary. In this paper, a computational approach is presented to assess the effect of different load-related and environmental factors on the durability of steel bridge components using detailed finite-element (FE) models that were calibrated using data from inspection reports of real bridges. It is shown that this computational approach, with certain assumptions, is capable of quantifying the damage due to loading and environmental factors. This approach is also used to study different scenarios of how this damage could potentially affect the life of steel bridge components as loading and environmental conditions are varied. Results from the research reported in this paper show that the effect of increasing trucks weight limits on these bridges can be quantified and used to generate deterioration curves for the various bridge components. This information can also be used by highway agencies to streamline bridge maintenance and operations.

Box structures have been commonly used under highways. They are installed at grade or at great depths. When a box culvert is buried at a shallow depth, vertical pressure and dynamic impact due to traffic loading transferred onto the roof of the culvert can induce deflections of the culvert. The effect of the traffic load on the response of the culvert depends not only on the magnitude, pattern, and speed of the traffic load but also on the pavement structure. To investigate these factors, a reinforced concrete box culvert under three roadway sections (concrete pavement, concrete shoulder, and unsurfaced fill) was tested under static and traffic loads. The total thickness of pavement layers was 0.65 m within the pavement section and decreased gradually towards the end of the culvert through the shoulder and the unsurfaced section. The culvert was instrumented with displacement transducers under the roof and pressure cells on top of the roof within the unsurfaced fill. A low-boy truck with a known axle configuration and load was used to apply seven static load combinations and traffic loads at different speeds. Deflections under the roof and pressures on the roof were measured. The test results show that the magnitudes of the deflections of the culvert roof under static loads were generally increased from the concrete pavement, the concrete shoulder, to the unsurfaced fill. The truck at a higher speed generally induced more deflections than that at a lower speed or stationary.

Offshore tension leg platforms (TLPs) is often subjected to critical environmental loads that cause serious damage; Mars TLP in Gulf of Mexico, damaged by hurricane Katrina in the year 2005 is an example. Existence of external perforated cover reduces hydrodynamic forces on the existing members caused by direct wave impact. Although many studies confirm this fact but variations in the water particle kinematics along the water depth needs a detailed investigation to verify the phenomenon. Geometric configuration of the column member of the damaged MARS TLP is modeled on a 1:100 scale with an external perforated cover. Variations of water particle kinematics of the column member encompassed by perforated cover are presented through detailed computational fluid dynamics (CFD) analysis. Traces of the horizontal water particle velocity along the water depth are derived for a wide range of sea states for various chosen geometric configuration. Results of the numerical studies show that there is a significant reduction in the water particle velocity, which verifies the fact of reduction in forces on the column members. The research reported in this paper has a direct application in the repair of damaged column members by encompassing with outer perforated cover.

As industrialization advances, the increase in impermeable areas in urban regions has changed the water circulation system. Hence, many environmental issues such as heat islands and city floods have arisen. To solve this issue, related research with a high budget allocation is currently being carried out. A method of addressing this issue is to utilize permeable block pavements. The bearing capacity and hydrological efficiency of permeable block pavement with different base types was evaluated in this study using two accelerated pavement testings (APTs). Rutting was evaluated by performing a comparative analysis in each permeable block pavement. Furthermore, the hydrological characteristics were reviewed through a rainfall simulation experiment. The results of APT show that performance of permeable block pavements varies depending on the base type and traffic volume. Based on the result, it was demonstrated that the permeable block pavement is applicable for a vehicle road as well as the sidewalk. In addition, it was demonstrated that this pavement can improve the water circulation system.

Façades play an important role in buildings’ energy demand, and their state of conservation obviously influences thermal performance. The energy performance gap in existing residential buildings due to façade conservation status has not been analyzed in depth. In order to facilitate the systematic analysis of this influence, a system for classifying façades and their corresponding anomalies was developed for the first time. The classification system includes 23 types of façades and eight types of anomalies. It was verified by a panel of experts, and a case study was carried out with a sample of 154 buildings. An analysis of the results showed that the classification system is useful for a future analysis of the energy performance gap in existing residential buildings.

This paper presents the result of research efforts to better understand engineering behavior of historic masonry monuments at the Ayutthaya UNESCO World Heritage site in Thailand. Two dominant styles of Thai historic masonry monuments, bell-shaped and corn-shaped, were investigated. In the first stage of modeling, both styles of monuments were analyzed under their own weight using homogenized material properties. In the second stage, frequency analyses were performed to identify their vibration properties and dynamic response ranges. Finally, in situ ambient frequencies of two monuments were measured and compared to analytical frequencies. It was found that although the principal compressive stresses for both styles of monument were within safe limits, the safety factor against crushing around the entrances of the corn-shaped monument was found to be low. Moreover, there exist unexpected tensile stress fields around the upper middle part of both styles that might have been the cause of cracks commonly found. More consistent dynamic characteristics, such as frequency, were found when the underlying clayey layers were incorporated in the model. With critical stress zones identified, future strengthening programs for these monuments could be more precisely designed. Tension cracks and subsequent damages could be prevented. The soil-structure interaction model proposed will ensure that no threatening modes of failure such as torsion will be overlooked.

The objective of this research is to evaluate the reliability of bridge decks that use nonconventional materials or structural forms such as externally restrained deck systems where the available deterioration models developed for conventional systems are not applicable. The method developed here adopts the reliability theory and establishes a deterioration model for such bridge decks based on their failure mechanisms. The externally restrained deck is an innovative structural system introduced about a decade ago to the construction industry and provides corrosion-free replacement for conventional reinforced concrete decks. Because there is no established deterioration model available for these innovative systems, it is difficult to predict the reliability of such bridge decks at different instances of time. The developed method has been applied to an innovative structure with an externally restrained deck system, namely the Crowchild Trail Bridge, in Calgary, Canada, as a case study. A finite-element model of the bridge has been developed and calibrated with experimental results giving static deflection, vibration characteristics, load distribution, and crack patterns. The system reliability has been determined at different times using the proposed method. The results show that the design is quite conservative and there is a very low probability of failure for such a system during its design life.

This paper discusses the partial collapse of John Purdue Block, a historic masonry structure in Lafayette, Indiana. The collapse occurred while the structure was being renovated and modified to prepare it for a new occupancy and usage. Prior to the start of the project, masonry strengths were not assessed or even estimated, and the primary structural elements were not analyzed for the proposed changes in loading and geometry. Relatively modest loads on the masonry walls and columns, coupled with a long-term performance without distress, may have provided a false sense of confidence that the structure could safely withstand comparatively minor changes in geometry and loading. Subsequent testing and analysis revealed the cause of the failure to be localized compressive stresses that exceeded the ultimate capacity of the brick masonry.

Meeting user needs, expectations, and aspirations are the prime objectives of a facility provider; hence, it is necessary to evaluate a built facility while considering meeting user needs/expectations. Among present methods in vogue to elicit user feedback, the questionnaire remains the foremost and most common tool. The quality of feedback and its subsequent analysis entirely depend on the robustness of the questionnaire, which in turn depends on its content. Because questionnaires currently used to gauge user satisfaction are subjective, obtained feedback does not necessarily reflect actual performance. It is necessary to develop a survey instrument that can gauge user satisfaction as objectively as possible, that truly reflects ground reality. A questionnaire was developed based on carefully chosen attributes and the characteristics describing these attributes. A pilot survey was conducted to check its translation, construct, and consistency validity. Despite the increased number of questions, the offered objectivity will have a highly productive immediate and long-term impact on the performance of built facilities.

The observation of failure patterns of different reinforced concrete structures due to earthquakes in several countries has caused critical concern about the performance of beam–column joints. Retrofitting of reinforced concrete (RC) structures can lead to increased stiffness, strength, and failure deformation. This paper introduces a new type of reinforcement detail for the RC jacketing of nonductile exterior beam–column joints. Experimental investigations were carried out on five types of joint specimens keeping a scale ratio of three and were subjected to reverse cyclic loading. The improvement in performance was observed for the retrofitted non ductile exterior beam–column joints using the new RC jacketing than the conventional RC jacketing.

The aim of the present research is to investigate the effectiveness of the falling weight deflectometer (FWD) to simulate the traffic loading in the case of asphalt pavements that have been cold in-depth recycled (CIR) using foamed asphalt (FA) as a stabilization treatment for base works. The investigation is related with the need of understanding the behavior of asphalt CIR pavements under repeated traffic loads that can result in the prediction of pavement performance and contribute in the optimization of pavement design or redesign. For this purpose, a testing experiment was conducted to monitor and document the in situ developed strains under both FWD loading and truck loading, and to compare them with the calculated ones from finite-element (FE) linear elastic analysis. The developed strains were measured using a fiber optic sensors (FOS) system. The collected data were processed and analyzed taking into account the local conditions. The analysis results indicated that the maximum tensile strains from FWD loading were similar to the values generated by traffic (truck) loading. This was more evident at the bottom of the FA recycled layer.

Monitoring of breakwaters is a key aspect to prevent failures that affect the safety and quality of service. Unmanned aerial vehicle (UAV) photogrammetry gives low-cost and accurate geometric data, flexibility, and productivity to perform aerial surveys, although the weather conditions restrict flights for wind speeds above $50\mathrm{km}/\mathrm{h}$ (the Mikrokopter system). Despite the promising potential of these systems, its ability to monitor movement of cubes in breakwaters has not yet proven. The UAV photogrammetry is tested for the research reported in this paper in the Baiona breakwaters (northwestern Spain). A SD of 0.026 m is obtained from the point cloud. The detection limit of the system is evaluated and rotations lower than 1° could be detected. This value is calculated from the measurable differences in height values after the virtual rotation of a single cube. The system provides the exact position where the movement of the cube is produced and can be easily integrated with geographic information system–based management systems.

Soil-cement mixed piles are widely used to improve soft subsoil. But in regions with high-salinity groundwater, the soil-cement is susceptible to deterioration. At present, however, the design code for soil-cement pile composite foundations does not consider the deterioration effect of soil-cement. The saltwater region in the Yellow River Delta of China is used as a case study. Based on early strength tests of soil-cement, a practical prediction method for the lifecycle bearing capacity of soil-cement piles is put forward, and the influence of deterioration on the settlement of composite foundations is studied using model tests and numerical simulation. The prediction method of pile bearing capacity considers the progressive deterioration of soil-cement, and it shows that the deterioration of soil-cement has a great influence on bearing capacity of mixed piles with an increase in age, and the loss ratio of bearing capacity quickly reduces with a decrease in pile diameter. The deterioration also increases the settlement of composite foundations. Furthermore, pile defects aggravate the deterioration effects of soil-cement piles on the settlement of composite foundations.

This paper provides background on the use of lightweight aggregate concrete in long-span bridges. Observed time-dependent deflection of long-span lightweight aggregate concrete box-girder bridges is highlighted. The paper also summarizes the instrumentation program for health monitoring of the new Benicia-Martinez Bridge, which was recently completed in Northern California. Initial service performances of the bridge are assessed through deformation measurement of the superstructure. A primary objective of the instrumentation program is to identify time-dependent effects attributable to creep and shrinkage for future design and analysis of long-span bridges constructed of high-strength lightweight aggregate concrete.

This article discusses the evaluation of a posttensioned concrete structure exhibiting cracking using nondestructive evaluation, laboratory testing of concrete samples, and subsequent in situ load testing. During a field survey, it was identified that the posttensioned beams exhibited visually apparent deflections. An engineering evaluation was initiated to identify the cause of this type of cracking in the posttensioned structural system. Following a field survey and document review, an analysis was initiated for the estimation of potential posttension losses and analytical expected deflections for the purposes of comparing it to measured deflections in the field. After the analytical phase, an in situ, nondestructive evaluation phase and a subsequent material testing phase were initiated. The in situ evaluation of the structure involved nondestructive testing of concrete slabs and beams using ground-penetrating radar (GPR) to locate tendons. Cores were removed, and compressive strength testing and petrographic analysis of the cores were performed in the laboratory. Based on the review of the findings of the engineering analysis, nondestructive evaluation, and laboratory testing, the concrete beams and slabs were load-tested in accordance with ACI 318, Chapter 20. The load test served to verify that the structure could safely sustain the service load requirements of the building code. This paper should be of value to consulting engineers engaged in condition assessment of posttensioned structures exhibiting distress, in terms of the test methods used and the methodology used in developing various aspects of the load-testing program.

This paper presents the results of the experimental study on the thermal cracking of the wall of rectangular reinforced concrete (RC) tank. The tank is located in the sewage treatment plant in Żywiec, Poland, and has capacity of $\mathrm{27,500}{\mathrm{m}}^3$. Since the tank was designed without the expansion joints, it was constructed using the lean concrete mixture and low-heat cement to minimize the potential for thermal cracking. The temperature sensors were installed in both the primary and the complementary segments of the wall. In addition to the temperature data, the paper also presents the results of measurements of longitudinal concrete deformation, of crack development, and crack width on both surfaces of the complementary segment. The results of measurement of concrete strains and crack width development in vertical construction joints are also discussed. The current paper is the first one in a two-part series, and it contains the data collected from the actual RC rectangular tank. The second paper of this series will compare these experimental data with the results obtained from an advanced numerical model.

Semimassive RC tank wall may crack in the period of concrete maturing due to hydration heat, ambient temperature, solar radiation, and the restraint of thermal strains. The objective is to investigate a different cracking type of the northern and southern surfaces caused by different sunlight intensity operating on the exposed tank walls. This proposition was confirmed by the in situ investigation presented in Part I, followed by measurements with the use of embedment vibrating wire sensors for concrete strains and reinforcement bar stresses and by numerical calculations (Part II). Moreover, the crack width in the interior of the wall was twice as wide as the crack width found on the segment surface. Furthermore, to extend Part I, analytical and experimental results of concrete strains, steel stresses, and cracks are compared and discussed. The analysis covered a viscous-elastic concrete model where concrete mechanical properties constitute the function of hydration degree. In the analysis, a viscous-elastic concrete model with cracking was used, where concrete mechanical properties constitute the function of a hydration degree.

The presented studies have been conducted on the scope and magnitude of damages inflicted by earthquakes over the years. Many RC buildings, designed and constructed in the 1960s and 1970s, have serious structural deficiencies, especially in their beam-column joints. Such deficiencies result from inadequate joint shear strength or confinement of column reinforcement. The joints require elaborate retrofit measures to ensure the performances comparable to those of new designed structures. In this research, a new seismic retrofitting method is presented for beam-column joints based on the two-dimensional enlargement of the joint by using steel plate, angles, and posttensioning rods. The seismic adequacy of deficient RC beam-column joints, and the efficacy of steel plates and posttensioning rods, have been investigated for retrofitted joints through experimental and numerical analyses. According to the results obtained through investigations, this new rehabilitation scheme is effective, simple to install, and nondisruptive to the function of the building. The behavior of the experimental results has also been successfully predicted by a finite-element model.

Structures designed according to performance-based seismic design (PBSD) are required to satisfy the target performance. PBSD requires extensive research for capacity evaluation and development of reliable nonlinear models. Shear walls are the ideal choice to resist lateral loads in multistoried RC buildings. They provide large strength and stiffness to buildings in the direction of their orientation (in-plan), which significantly reduces lateral sway of the building. Experimental studies on nonlinear behavior of shear walls of medium aspect ratios are limited. Nonlinear performance of medium aspect ratio shear wall specimens are studied on three identical shear wall specimens through application of monotonic and cyclic loading. In order to study the effect of axial load on the flexural behavior and ductility of shear wall, a parametric study is conducted using a layer-based approach, which is used to generate the analytical pushover curve for the shear wall and validated with the experimentally evaluated pushover curve of the tested shear wall. A comparison is made between monotonic and cyclic load behavior. Stiffness and strength degradation and pinching parameters are evaluated from cyclic tests. Plastic rotation limits and ductility capacities under monotonic and cyclic loading conditions are compared with recommended values.

Although they are the safest method of transporting oil and gas, pipelines are still subject to different degrees of failure and degradation. It is therefore important to efficiently monitor oil and gas pipelines to optimize their operations and to reduce their failures to an acceptable safety limit. Several models have recently been developed to predict oil and gas pipeline failures and conditions. However, most of these models were limited to the use of corrosion features as the sole factor in assessing pipeline condition. In addition, the use of internal corrosion features in the condition assessment requires the pipe to be piggable, which is not always the case. Modifying pipelines with pigging facilities is not always an easy option and can be very costly and time consuming. This paper presents the development of condition forecasting models for unpiggable oil and gas pipelines based on factors other than those related to internal corrosion. In addition, the paper examines the degree of confidence of the unpiggable model by comparing its results to those obtained using piggable models. Unpiggable models can save both time and cost of usual scheduled in-line inspections. Regression analysis, artificial neural network (ANN), and decision tree techniques were used to develop the models based on historical inspection data of existing pipelines in Qatar. All necessary statistical diagnoses have shown sound results for the developed models. When they were validated, the models showed robustness with a satisfactory average validity percentage.

Experimental and analytical modal analysis and in-operation vibration measurements were performed on the massive concrete structural floors of several structurally connected ‘units’ of a six-level, multitenant industrial complex with total floor usable area exceeding $0.1{\mathrm{km}}^2$. The aim of the systematic study was to characterize vibration sources and factors that affect vibration serviceability, which is a major concern when changing usage patterns lead to conflicting requirements for vibration generation and tolerance for different types of industrial/commercial user. This was a rare investigation aiming to provide information on specific performance and relevant technologies for occupancy decisions by tenants and building management of similar structures. Floors evaluated were within different types of industrial single-occupant unit stacked up to six levels and having multibay floors with spans up to 12 m with first vibration mode frequencies greater than 8 Hz. These “high-frequency floors” display typical transient response behavior to footfalls, with response levels controlled by modal mass. Units were studied in typical operational conditions including warehousing, instrument assembly and testing, light electronic/mechanical manufacturing, and machining. Vibration sources included internal and external vehicles, human footfalls, and machinery. The study showed the most onerous form of loading to be forklift trucks and that higher level floors of the same type were least serviceable. Experimental modal analysis showed a surprising range of modal properties for nominally identical floors of the same type and the relevance to performance of modal mass.

The vulnerability and robustness of in-service cable-stayed bridges under a marine atmospheric environment is studied based on several specific considerations in modeling corrosion-induced damage in cables. With the limited test data available, the corrosion model for cables exposed to marine environmental conditions is modified to reflect the coupled effect of cable in-service stress level with an assumed probability distribution of corrosion of steel wires along a cross section. To ideally capture the dynamic effect caused by corrosion-induced rupture, the complete sudden element removal strategy is simulated by using computer software developed by the Pacific Earthquake Engineering Research (PEER) Center. In the assessment of bridge vulnerability, the stress transfer coefficient is introduced as well as normalized corrosive section area to reflect the major propagation of stress within adjacent cables. The so-called performance index combined with the definition of critical failed pairs of corroded cables is applied to evaluate the influence of corrosion on the robustness of cable-stayed bridges. The results from a case study on a 1,088-m span cable-stayed bridge reveal that the optimal geometrical configuration of a bridge deck would be possibly adversely altered if corrosion is severe. The bending moment at the bottom of the towers exhibits a considerable increase of 171.6% after 20 years of corrosion. In any corrosion case, all the vulnerable cables are distributed near the towers. Among five regions defined in the analysis of robustness, cables in the side span, i.e., Region 4, are most robust in any case, although this region is most sensitive to preliminary corrosion. Comparatively, cables located within the $1/4$th main span and main towers, i.e., Regions 2 and 3, are not only sensitive to initial corrosion-induced damage but also more likely to reach their allowable stress level.