Journal of Performance of Constructed Facilities

The impact-echo method is a popular non-destructive testing method in civil engineering. The present work proposes the virtual edge extension technique to overcome the edge effect, which is a major issue during impact-echo testing. The virtual edge extension technique utilizes wave energy absorbing mediums (e.g., water) temporarily brought in contact with the concrete edges to mitigate the misleading signal clutter. In order to conduct this study, an instrument called constant amplitude impactor has been developed to produce constant source waves to facilitate comparison of wave characteristics. The effectiveness of the wave attenuation/absorbing characteristics of four different mediums have been investigated in the present work. It has been demonstrated that the depth could be evaluated from noisy signals and smaller defects (of size 20 at 100 mm depth) could be identified in concrete blocks. Encouraging results indicate that the virtual edge extension technique is useful in improving the non-destructive evaluation using impact-echo method.

This paper aims to determine the dynamic characteristics, such as natural frequencies, mode shapes and damping ratios, of two different domed structures, namely Hamza Paşa Mausoleum and Kavak Meydan Fountain, built in the sixteenth century by experimental methods. The experimental dynamic characteristics are used to develop initial analytical models and update these models. Analytical models of the structures are constituted using finite element theoretical software, and dynamic characteristics are determined analytically. The experimental measurements are carried out by operational modal testing under environmental loads, which are wind and traffic loads, and the dynamic characteristics are identified experimentally. Vibration responses are collected from the dome’s outer surface for Hamza Paşa Mausoleum and the dome pulley’s inner surface for Kavak Meydan Fountain. Measurement time, frequency span, and effective mode number are determined by considering pretest measurement results. At the end of the study, analytical and experimental dynamic characteristics are compared with each other and the finite element models of these domed structures are updated by changing material properties and boundary conditions.

Postearthquake fire (PEF) can result in a catastrophe even worse than the earthquake itself. Investigating the effect of PEF loads on structures is thus of paramount importance. On the other hand, because of the complexity of fire, the simulation to account for the thermal loads exerted on structures has always been an issue. Although there are two main methods for simulating real fires—standard fires and natural fires—observations have shown that both of these are more correct for small/medium-size structures. For large open-plan structures, alternative methods (such as traveling fires) should be used. Here, an investigation is performed on a tall seven-story steel moment-resisting structure with a plan area of $900{\mathrm{m}}^2$. The structure is first pushed to arrive at a target displacement corresponding to the life safety level of performance according to FEMA code. The damaged structure is then subjected to different traveling fire sizes of 16.7, 50, and 100%. To draw a comparison between the results, a uniform fire (the ISO834 curve) is also considered. The results show that the structure fails at 12, 9, 11, and 16 min under the 16.7% fire size, the 50.0% fire size, the 100% fire size, and the ISO834 fire curve, respectively. The results confirm a considerable difference between the results of a uniform fire and those of traveling fires. It is therefore concluded that the structure is shown to be more vulnerable to PEF loads when the traveling fire methodology is used to calculate the fire resistance.

This paper provides a risk-based assessment of the sustainability of structural design alternatives in hazard-prone regions. Little systematic research has been done to assess the economic, social, and environmental cost of sustainable construction in relation to hazard resilience or the impacts of hazard-resilient design on system sustainability. However, some studies have suggested that green construction practices might compromise the objective of the design of hazard resistance of a building, whereas others have highlighted that the impacts of natural hazard damage are unsustainable, given the costs of reconstruction and threats to public safety, among other consequences. This paper extends the performance-based engineering paradigm beyond traditional metrics of structural performance to quantify such sustainability metrics as monetary cost, embodied energy, emissions, casualties, and downtime. The upfront environmental and economic costs of sustainable design alternatives are then compared with hazard-induced risks, considering uncertainties stemming from the hazard, damage assessment, or sustainability analysis. The sustainability analysis is illustrated for both bridges and buildings sited in seismically prone regions, revealing the potential trade-off in upfront costs and lifetime sustainability attributable to hazard exposure.

This paper addresses field investigations of the performance of masonry buildings during the October 23 (Erciş) and November 9 (Edremit), 2011, Van earthquakes in Turkey. Erciş and Edremit are villages respectively located 90 km and 18 km from the city of Van in Turkey. Ground accelerations and response spectra for these earthquakes are discussed. A total of 28,000 buildings were damaged or collapsed in the city center and surrounding villages after the Erciş earthquake. This number increased to 35,000 after the Edremit earthquake. Almost all masonry buildings were affected in the region. Most of them in the area were constructed of random or coursed stone walls with no reinforcement to support heavy clay tile roofing over wooden logs. A large number of such buildings were heavily damaged or collapsed. Cracking and failure patterns are examined and interpreted according to current provisions for earthquake resistance of masonry structures. From the field investigations, it is shown that damages had several causes, among them site effect, location and length of the fault, and poor construction quality. In addition, the two earthquakes hit the masonry buildings within 17 days, causing progressive damage. A large number of nonengineered masonry buildings completely collapsed or were heavily damaged. Most of those in the affected area were not designed and constructed in accordance with the Turkish Earthquake Resistant Design Code.

In 2013, there were 14 killer tornadoes in the United States that caused a total of 55 fatalities. The most severe tornado in this group was an Enhanced Fujita (EF) 5 storm that occurred on May 20 in Moore, Oklahoma. Because of the severity of this storm, a field investigation was undertaken to observe and document damaged commercial and residential structures so that a better appreciation of their structural and nonstructural performance could be developed. Both low-rise engineered commercial buildings and single-family homes were surveyed. Most of the commercial buildings sustained severe nonstructural damage and limited damage to the primary structural system. However, some instances of global structural collapse and local collapse of structural elements around building entrances were also observed in commercial buildings. Residential construction exhibited extensive damage to brick veneer and failure of garage doors and subsequent roof damage. These failures illustrate the importance of an adequate load path from the building façade back into the primary structural system. Furthermore, maintaining the integrity of the façade and roof systems is critical because failure of these systems was observed to change the loading and support conditions of key structural elements, which then precipitated damage to the primary structural system.

Most industrial buildings in developing countries such as China have excessively high energy consumption, and the portion used by HVAC systems is significant. This investigation used a winery building in a cold region in northern China as a case study to analyze industrial-building energy performance. A lack of communication, cultural differences in design requirements, and poor construction quality were the primary factors that led to excessive air leakage, insufficient building insulation, and poor indoor air distribution. This investigation developed a set of methods to evaluate building-energy use, air leakage, condensation, thermal insulation, and indoor air distribution. A number of remedial measures were proposed, and some of them have been proven to be effective. In developing countries such as China, the lessons learned in this project will be useful for designing and constructing energy-efficient industrial buildings with desirable indoor environments.

In this paper, an existing beam-on-springs modeling methodology is examined for suitability in estimating vertical displacements and joint movement in jointed pipe culvert systems. Methods of determining the modulus of subgrade reaction, $k_s$, are used in beam-on-springs modeling and compared with results from laboratory tests on three buried culvert pipes. Pipes were buried in soil conforming to AASHTO specifications for buried structures and then loaded at the ground surface. Two of the methods provided reasonable estimates of $k_s$ for use with both rigid and flexible test pipes (with an average error of 25%). The first method relies on empirical parameters, whereas the second method relies on actual soil properties to estimate $k_s$. This makes the second model more appealing. However, the second model is somewhat less accurate than the first (10% average error compared with 25% average error). Movement at the culvert joint was estimated by beam-on-springs modeling with a moderate degree of accuracy (within 52% error when calculating the maximum movements) because of the complexities of the jointed culvert system being modeled. Accordingly, results from a beam-on-springs model should be used conservatively.

A previous study using a scaled-down model of single-room masonry structures tested on a shaking table has shown that strength may be considerably increased by tying up the masonry walls by polypropylene (PP) bands, wrapping the walls using steel wire mesh, and providing horizontal L-shaped reinforcing bars at corners. The effectiveness of the same economic approaches and their combinations has been studied for similar scaled-down models with proportionate openings representing doors and windows, as a logical further scope of the previous study testing these models on a shaking table. As the presence of openings influences the crack and damage propagation leading to failure, the present study may give a more realistic picture of the seismic behavior of masonry structures with openings. Experiments have shown that PP bands were more effective than horizontal L-shaped reinforcing bars in arresting cracks and preventing collapse of the models, even those severely damaged. Further, the most important aspect of the study is that the technique is economical and can be implemented without involvement of any technical manpower or sophisticated equipment. The interesting observations regarding the effectiveness of such economical strengthening measures obtained from the study may be helpful for seismic strengthening of real-life masonry structures with door and window openings, leading to broad guidelines in this direction.

Soft-story woodframe buildings have been identified as a disaster preparedness problem throughout California and are present in many other states of the United States. These buildings can be readily identified by their large openings at the ground floor, often for parking, which results in a soft and weak first story that is prone to collapse in moderate to severe earthquakes. This paper presents the hybrid test results of a full-scale collapse test program that was carried out on a 3-story soft-story woodframe building with an overretrofitted first story. The overretrofitted design was constrained to the soft story only, essentially representing a retrofit that would likely drive the soft-story failure mechanism into the upper stories. The objectives of the collapse testing were to (1) quantify the collapse shift into the upper stories when the first story is overstrengthened, (2) investigate the collapse mechanisms of a woodframe building constructed with archaic building materials and style in the upper level, and (3) investigate the collapse capacity of the unretrofitted structurally deficient upper stories composed of archaic building materials. The overretrofitted design and collapse testing with results are presented in this paper. Even when overstrengthened, a very high-intensity earthquake, approximately 125–150% of the maximum considered earthquake, is required to collapse the archaic assemblies found in the upper stories of soft-story woodframe buildings. This high-intensity earthquake caused a 6.7% residual drift in the upper two stories which resulted in multiple fastener push-outs and dramatic softening (as indicated by the change in fundamental period). The collapse capacity of the archaic and unretrofitted upper two stories was approximately 20-kN lateral strength and 8% lateral drift.

This paper is intended to review the main causes and mechanisms of bridge collapse. The common factors resulting in bridge collapse are first reviewed. These factors are classified into two broad categories, namely, natural factors (including flood, scour, earthquake, landslide, debris flow, hurricane, typhoon, wind, etc.) and human factors (including imperfect design and construction method, collision, vehicle overloading, fire, terrorist attack, lack of inspection and maintenance, etc.). Then the collapse modes of a few major types of bridges are reviewed and some relevant measures adopted in the current practices are discussed. It is hoped that this paper will provide a concise but comprehensive summary of information needed by researchers and engineers to understand the collapse mechanisms of the major bridge types and how the current practices deal with these issues. Meanwhile, much effort is made to identify future research needed to better understand this topic and to find better solutions to address the existing issues.

The ultrasonic detecting method and repair technology based on fatigue crack features in steel box girder are addressed in this paper. Based on the fatigue crack features in steel box girder, standard specimens with different crack features which primarily include length, width, depth, angle and location, were manufactured in the laboratory. Cracks were detected using ultrasonic techniques (UT). Through the analysis of flaw echo parameters, some methods to detect crack features are proposed. The $K$-value method is used to distinguish crack locations, which start from the weld toe, weld root, and the invisible parts in the U-rib. A new method, namely the one-third-length measurement method concerning the crack angle and position, is proposed based on the test results. An inclined hole is applied to stop the extension of the inclined cracks according to the detection results. Its performance was analyzed using the finite-element method, which showed that the inclined hole could reduce stress concentration effectively and has better stress distribution than the normal vertical stop holes.

The vibration serviceability of an as-built long-span concrete floor was assessed using field measurements taken during the structure’s daily use and under controlled human activities including a group of people walking and jumping at specific frequencies. The floor serves as the waiting hall of a railway station and has a unique external prestressing system. The measured natural frequencies and recorded accelerations were compared with threshold values specified in design guidelines. The fundamental frequency of the floor was estimated to be approximately 2.2 Hz, which does not satisfy the requirements of current Chinese design codes for concrete structures and PCI design guidelines. The recorded vibrations were much lower than the vibration amplitude thresholds specified in several design codes for similar types of structures. This positive result is consistent with interview results from users stating that there have been no complaints from passengers or station staff relating to the floor’s vibration performance since the station was open to the public three years ago. Unless the external prestressing system is changed, numerical analysis demonstrates that it is too expensive and in some cases technically impossible to increase the natural frequency of a floor to 3 Hz to satisfy the recommended threshold value. The authors conclude that the frequency threshold value given in the current Chinese code and PCI design guideline is too strict for this floor. An approach that sets a vibration amplitude threshold seems more appropriate for assessing the vibration serviceability of this kind of long-span concrete floors. A multiplication factor of 30 to the ISO vibration baseline curve is recommended as an appropriate assessment criterion for floors serving as waiting halls in railway stations. Vibrations of the floor under different volumes of users were recorded and analyzed to capture the influence of crowd configurations on the vibration. Observations revealed that the vibration induced did not show much dependence on crowd configurations. Besides, floor vibrations under various group sizes were investigated. Even though they were found to be dependent on group size, the floor vibrations did not change linearly with group size as a result of imperfect synchronization.

Cold-formed steel-stud walls have been utilized as an attractive option for blast-resistant design due to the combination of high strength and ductility that enable them to absorb and dissipate blast energy through large deformation kinematics. However, achieving the available ductility of the steel studs requires special attention to the stud-to-track connection details, which has remained an active area of research and development. While much of the existing literature has described specialized ideal boundaries to ensure that the full tensile membrane response of the studs would be achieved prior to connection failure, the research reported in this paper examines the blast performance of cold-formed steel-stud walls with commercially available connections and bridging. Experimental results from a series of three open-arena blast tests of identical cold-formed steel-stud wall panels are presented. Distortional buckling of the studs around unstiffened punchouts in the web as well as web crippling adjacent to the screwed stud-to-track connection are highlighted in this paper. The results from the research reported in this paper are particularly important since several of these modes of failure have not been investigated in static load tests designed to develop resistance functions for cold-formed steel walls.

In this paper, the structural behavior of nine historical brick masonry minarets in Isfahan, which were built in the eleventh and twelfth centuries A.D., against weight, temperature, wind, and earthquakes is studied. A nonlinear three-dimensional FEM has been used. To investigate the effect of the central column and spiral staircase on the structural behavior, analyses have been performed for two cases: (1) the complete minaret, and (2) only the outer shell. The structural analysis of minarets under temperature changes shows that for certain inner and outer temperature differences, the minarets fail. Minarets do not fail because of the maximum wind velocity of Isfahan. All minarets fail when subjected to imposed earthquakes. By decreasing the minaret height or increasing the material strength, failure is delayed. Changing the failure criterion or damping ratio has little effect on the failure of the minarets.

Modeling the service life of building components is a key requirement for several purposes, including the implementation of an effective and efficient asset-management system, life-cycle assessments, or life-cycle cost calculations. Because the phenomena underlying the degradation of building components is highly complex, it is common to use statistical approaches for modeling purposes. This paper is focused on the statistical modeling of the service life of the wood frame doors and windows of the National Palace of Sintra. A review of the main factors of degradation of traditional linseed-based painted wood frame doors and windows and of the approaches that have been used to model the service life of building materials and components is presented. The influence of the exposure to weather agents on the degradation rate of external wood frame doors and windows is investigated and a model to estimate the average condition level is proposed. The proposed model takes into account radiation and wind-driven rain and their interaction in the degradation process.

China is addressing the significant challenge posed by the construction of several 300-m-high arch dams for the effective use of hydropower resources. Limited experience has been gained globally in the construction of super-high arch dams. Moreover, the present design codes are based on past experiences with arch dams with significantly lower height. Stress computation consists of many analytical simplifications. In addition, numerous questions may be raised regarding the reliability of this computation for application to super-high arch dams. This study therefore presents an integrated analytical approach to simulate the actual working performance of super-high arch dams. This approach emphasizes the significance of the analytical descriptions on four actual factors: (1) actual material, (2) actual structure, (3) actual load, and (4) actual process. Furthermore, the effectiveness of the actual working performance simulation has been proven by updated engineering practice.

In thermal power plants, coal-storage-yard structures play a major role in the production of power. Coal storage capacity is limited by the design level. If the design limit is exceeded, the reinforced concrete (RC) coal storage structure may undergo deterioration with varied cracking patterns and ultimately collapse. Through quick, early observations, engineers, construction managers, and others may be able to avoid major structural disaster and the associated risk to human life. Structural problems could cause the entire plant to shut down, and the down time may cost more than additional coal storage; thus, repair and rehabilitation has to be approached with cost-effectiveness in mind. The cause of the distress and failure mechanism of the actual damaged RC frame structure are evaluated and analyzed in this paper. The analyses are carried out using finite-element analysis with real life loading and other conditions, and based on the analysis, relatively economical rehabilitation strategies using structural steel members are proposed. During this process, it is suggested that the existing distressed and failed RC members be replaced with the proposed structural steel members under the supervision of the presiding engineer.

This article describes the cracking of a hydraulic cylinder pipe made of 32HA steel with an Ar-shielded gas tungsten arc–welded (GTAW) protective housing. Grade 32HA is a Polish grade of steel that contains approximately 0.32% carbon and is designed for use on pipes and tubes for hydraulic cylinders. A fragment of the cylinder pipe and a welded joint of the protective housing were subjected to light microscopy (LM)-based macro- and microscopic metallographic examination. Tests of mechanical properties and impact energy, measurements of hardness, and analyses of chemical composition were also carried out. It was determined that the primary reason for cracking was the overloading of the pipe with the pressure of the working liquid inside the cylinder during operation. It was also ascertained that the welding of the protective housing created a heat-affected zone in the steel; this HAZ was of a very hard and brittle martensitic structure consisting of a structural notch that increased the steel’s susceptibility to cracking in this area.

To deal with the existing building dilapidation problem in Hong Kong, a mandatory building inspection scheme (MBIS) has been introduced. The effectiveness of the scheme is reliant on an adequate supply of registered inspectors (RIs) to inspect and supervise repair works. To ensure that there is an adequate supply and demand of RIs to enable the implementation of the MBIS, a robust workforce planning model is proposed. The database of private buildings from the Hong Kong Home Affairs Department and a web-based survey were used to collect qualitative and quantitative data, from practitioners and professional bodies, to determine the demand and supply of labor. A quantitative modeling approach, which utilizes a labor multiplier method, revealed that there will be a shortage of RIs to meet future professional workforce demand under the MBIS. The qualitative aspect of the research reported in this paper, which addressed the perception of eligible RIs, revealed that the majority of respondents were disinterested with becoming an RI as their responsibility and liability had not been clearly defined under the current MBIS scheme. The findings provide the local government authority with the ability to visualize the workforce demand under the MBIS and articulate future workforce strategy to ensure an adequate supply of the professional workforce. As a result, the condition of buildings and the living environment of the general public will be improved with the implementation of MBIS to safeguard public safety.

Developing an efficient bridge condition evaluation procedure is economically critical to a state highway department; however, any adopted bridge condition approach needs to be accurate. A state highway department typically conducts a bridge condition evaluation by visual inspection on a 24-month cycle. During the evaluation, a bridge inspector visually inspects bridge components to derive a bridge condition rating on a 0–9 scale; a 0 value represents failure. The intrinsic weakness in a visual inspection system is the nonuniformity in the process due to the subjective nature of the approach. This paper proposes an approach to supplement visual bridge inspections by implementing gigapixel technology to promote quality assurance and control in a state bridge management system. The discussed approach supplements the visual inspection of a bridge with panoramic images to be later reviewed by a trained group of bridge engineers. This trained group of bridge engineers is enlisted in the inspection review process to promote uniformity in the bridge rating process. Additionally, the presented approach creates a bridge panorama that can be cataloged as a permanent bridge condition record in a state DOT’s structural health monitoring system. The presented approach uses gigapixel technology to create high-resolution panoramas that can be reviewed by an engineer using Google Earth tools. The hardware needed for gigapixel technology is inexpensive, but can greatly improve conditional bridge rating consistency between bridge sites.

Most long bridges have joints to accommodate thermal expansion and contraction without inducing large forces in the bridge. However, these joints have caused some adverse conditions during earthquakes. In addition, irregular topographical surfaces, creating substructures with pier heights of different lengths, can worsen the seismic vulnerability. This paper examines the seismic behavior of a multiframe concrete box-girder viaduct with four levels of altitudinal irregularity, ranging from regular to highly irregular, using fragility curves. To extend the results for all bridges in the same class, uncertainty related to the earthquake, structural geometries, and materials are considered. Full nonlinear time-history analyses are performed on the three-dimensional analytical finite-element models of the bridge. The results clearly indicate that the bridge fragility increases with the degree of the altitudinal irregularity. In addition, the component fragility parameters show that unseating of the deck at the in-span hinge location is the most vulnerable component.

Some structures, both military and civilian, might experience explosive loads during their service life. Owing to high uncertainties in blast load predictions and structural parameters, accurate assessment of the performances of structures under explosion loads is a challenging task. For example, a number of experimental studies using fiber-reinforced plastic (FRP) strengthening of RC structures have been reported in the literature. Most of these studies demonstrate that FRP strengthening is effective in increasing the blast load–carrying capacities of RC structures. However, significant variations in the effectiveness of FRP strengthening have also been observed owing to the large uncertainties in blast loading, RC and FRP material properties, and workmanship in preparing the test specimens and conducting experimental tests. Very few studies that take into consideration these uncertainties in analyzing the effectiveness of FRP strengthening of RC structures on blast loading resistance can be found in the literature. This study performs a reliability analysis to assess the performance of RC columns with or without FRP strengthening in resisting blast loads. Statistical variations of blast loading predictions derived in a previous study are adopted in this study. To define structural performance, pressure-impulse ($P\text{-}I$) curves with a damage criterion on the basis of axial load-carrying capacity that were developed in previous studies for RC columns without strengthening or with FRP strip, FRP wrap, or both FRP strip and wrap strengthening are used. Considering the uncertainties in blast loading predictions and RC column and FRP material properties and dimensions, limit-state functions corresponding to different damage levels of RC columns with or without FRP strengthening are formulated. The statistical variations of blast loading, RC column dimension, longitudinal and transverse reinforcement ratio, and concrete, steel, and FRP material strength and FRP thickness are considered. The failure probabilities of RC columns corresponding to different damage levels with or without FRP strengthening are calculated. The effectiveness of FRP strengthening on the RC column’s blast loading resistance capacities is discussed. The importance of considering the random fluctuations on blast loading and RC column parameters in assessing the blast loading effect on RC columns is demonstrated. A structural system reliability analysis is also carried out to examine the probability of structural collapse as a result of blast loading applied to the front of an example two-span multistory RC frame. The results obtained in this study demonstrate the effectiveness of FRP strengthening on structure protection and can also be used to assess RC structure performance under blast loadings.

An investigation of a new prefabricated composite floor system is described. The system consists of a reinforced concrete T-section with mechanical blockouts in the web whose concrete flange forms the deck; the concrete piers are connected to a wide flange steel beam at their bottom through headed concrete anchors and welded reinforcing bars. The steel beam carries the shear across the openings in the concrete web. The paper describes two experimental programs, the first using three short-span specimens, as part of a pilot study, to investigate the shear performance and the second using three full-scale panels to investigate the overall performance of the system. The floor system offers the potential for a prefabricated composite system using reinforced-concrete and standard steel sections. Practical applications include roofs and floors for parking structures, apartments, and office buildings.

This paper presents a comparison of three methods used to load rate the Powder Mill Bridge based on the load and resistance factor rating (LRFR) approach. This is a typical three-span continuous bridge with steel girders in composite action with the RC bridge deck. The three methods are as follows: (1) employing the conventional design office load rating technique using a simplified line girder analysis, (2) using strain measurements from a diagnostic load test to adjust the design office rating to account for in-situ bridge behavior, and (3) using a finite-element (FE) model of the bridge, which accounts for three-dimensional (3D) structural system behavior. Advantages and disadvantages of each method are related to speed, ease of use, reviewability, cost, accuracy, and type of use intended. Similarities and differences in utilizing these three methods are discussed. The advanced load rating methods are shown to produce higher ratings in comparison with the conventional approach.

Precast prestressed double-tee (DT) girders are considered a crucial element of modern infrastructure used to accelerate building construction worldwide. These girders can be deficient because of local damages and develop cracks as a result of improper transportation and handling. Therefore, it is very important to develop an efficient retrofitting technique in order to restore the lost capacity and/or even outperform it. The objective of this paper is to develop retrofit strategy of the deficient girders using the externally bonded carbon-fiber-reinforced polymer (EB-CFRP) technique and verify it using field data. A field test was conducted on three actual-size precast pretensioned DT girders having different levels of damage and retrofitted using CFFP sheets. The girder stems for two of them were strengthened in flexure using unidirectional U-shaped CFRP sheets, while all girders were shear-strengthened at their dapped ends. Each girder was loaded incrementally up to collapse while the deflection of the girder and normal strains developed on both concrete surface and the CFRP sheets were recorded at each load increment. Test results assured the adequacy of the adopted strengthening technique with respect to both ultimate capacity and ductility. In addition, the experimental flexural and shear resistances of the retrofitted girders are far greater than those obtained from equations available in design codes by at least 60%.

This paper provides a unique literature review of cracking defects developing in low-rise residential structures as a result of deformation caused by environmental loads and low-level blast vibrations. Characteristics of cracking and corresponding causes are reviewed with an emphasis on Australian brick veneer construction although findings are relevant to other construction types around the world. Factors affecting structural response to blast vibrations are examined and loads equivalent to blast vibrations are presented. The influence of expansive soils upon structures is briefly reviewed including a summary of soil shrink/swell behavior. The desiccating effects of vegetation are reviewed in addition to the role trees may play in contributing to damage. The findings of this research are of vital importance to damage investigations in areas experiencing low-level vibrations.

As a critical component of the national transportation network, bridges have received a lot of attention regarding their safety and condition state. Bridge superstructures begin to degrade after they are placed in service; to combat this issue, owners have begun to utilize a variety of technologies to monitor the behavior and detect different sources of damage in these structures and generate higher fidelity condition metrics. However, an appropriate maintenance decision-making process requires knowledge of the influence of detected damage and deterioration mechanisms on the overall system behavior. This paper presents a performance measurement and evaluation framework that can be used to characterize the impact of deteriorating conditions on the performance of in-service bridge superstructures. The framework was established based on a numerical modeling approach and was validated through a sensitivity analysis of two representative in-service composite steel girder bridges under the impact of corrosion in the girders, with an objective of evaluating the impact on functionality and operational safety. The sensitivity analysis utilized a series of nonlinear finite-element analyses to assess the system-level structural performance under a variety of damage scenarios. Results from the analyses demonstrated that the shape of the damage configuration has negligible effect on the capacity reduction in deteriorated structures, while the damage depth can significantly reduce the capacity of the structure (up to 60%). It is expected that the proposed framework for evaluating system behavior will provide a first step for establishing a critical linkage between design, maintenance, and rehabilitation of highway bridges, which are uncoupled in current infrastructure decision-making processes.

Because of columns loads, reinforced concrete (RC) continuous beams in skeleton structures are subjected to transverse compressive stress at support locations. Such lateral pressure can enhance the bond between the main top reinforcing bars and the surrounding concrete because of the confinement effect. Thus, the development length can be reasonably decreased compared to the case of no lateral pressure. However, different codes of practice, such as the Egyptian code standard ECP 203-2007 and the American Concrete Institute (ACI) code standard ACI 318-11, stipulate increasing the reinforcement location factor for upper reinforcement implemented in the calculation of the development length of such bars. On the other hand, the Comite Euro-International du Béton (CEB-FIP) model code standard CEB-FIP 2010 considers this enhancement in bond stress calculations as being due to transverse compression stress. To assess such effects, pull-out tests were performed on reinforcing bars embedded in short RC columns subjected to different levels of axial pressure. The experimental findings showed the same trend as manifested in the CEB-FIP 2010 results, where increasing the lateral pressure on the reinforcing bar resulted in decreasing the development length for both smooth and deformed steel bars. In contrast, the results of development length calculations based on both ECP 203-2007 and ACI 408R-03 were constant regardless of the level of lateral pressure on the reinforcing bar. This highlights the need for both ECP 203-2007 and ACI 408R-03 to consider the effect of transverse lateral pressure on development length calculations due to varying lateral pressure on the reinforcing bar.

Solutions of synthetic water-soluble polymers have been used for the construction of bored piles (drilled shafts) since the early 1990s. These engineered fluids are very different from conventional bentonite slurries but there is currently a serious lack of industry guidance. Despite their advantages over bentonite, performance issues have arisen in the past and foundation engineers remain wary of their use. To help practicing engineers avoid past pitfalls and to promote best practice, this paper presents a critical reappraisal of selected European case histories of bored piles constructed using polymer fluids. A collective reassessment is necessary in order to provide an overall picture of the situation as individual cases may show conflicting results. It is found that the completed piles can have excellent load–movement characteristics if polymer behavior is understood and respected. Conversely, excavation instability, structural defects, and poor pile performance can result if the special properties of these fluids are not fully appreciated and as a result they are not properly maintained. The findings presented in this paper will be useful for consultants and contractors when designing and constructing piles and diaphragm walls utilizing polymer fluids in the future.

The main purpose of this paper is to utilize lifecycle cost analysis (LCCA) as a decision-support tool for three commonly encountered decisions in bridge management: bridge deck overlay decisions, expansion joint replacement decisions, and deck widening versus deck replacement decisions. Bridge management systems aim to assess investment decisions and identify the most cost-effective improvement alternatives to ensure the safety and serviceability of bridge networks. To achieve this goal, the recently developed deterioration models and cost data for highway bridges in the state of Nebraska are utilized in conducting LCCA using deterministic and probabilistic approaches. For deck overlay decisions, silica fume overlay, epoxy polymer overlay, and polyester overlay are compared with bare deck with respect to lifecycle cost and structural life. In expansion joint replacement decisions, two alternatives are compared: relocating abutment expansion joints at the grade beam and replacing abutment expansion joints at the same place. Deck widening is compared with deck replacement under five different bridge conditions. The results of the analysis indicate that applying an epoxy polymer overlay on bare deck with a condition rating of 7 is the most cost-effective deck overlay decision, replacing an abutment expansion joint at the same place is more cost-effective than relocating them at the grade beam, and deck widening is significantly more cost-effective than deck replacement in most cases.

Exterior insulation and finish systems (EIFSs) are common in Europe nowadays. These systems bring thermal benefits, in addition to being cheap and easy to apply, but there are often serious problems with biological growth, causing cladding defacement. The physical phenomenon causing EIFS defacement is known, and mathematical models simulating its performance have been developed. However, no simple process exists to evaluate the risk of EIFS surface humidification (which contributes to surface defacement) that might be used by designers and by the building industry. This paper presents a methodology to assess EIFS surface humidification based on the definition of indices that combine the effect of surface condensation, wind-driven rain, and the drying process, three of the most prevalent parameters influencing surface moisture content. The proposed indices were calculated using data collected during a 1-year in situ test campaign, which provided information about the exterior climate conditions and the surface temperature and wind-driven rain on four EIFS-covered façades facing the cardinal directions. The indices were compared with the results of the surface moisture measured simultaneously, which allowed the methodology to be validated. This paper also presents an example of the practical use of this methodology using a definition of hazard classes of surface humidification of EIFS-covered façades located in Portuguese territory.

In the last few years, anonymous probe-vehicle data has become a reliable means to evaluate travel time reliability, as well as congestion conditions along highways and major arterials. The data is collected using telematics from commercial and private cellular phones, global positioning system (GPS) devices, and onboard vehicle computers. The probe-vehicle data is commercially available in 1 min increments along spatially defined roadway segments of varying lengths. This data is being incorporated into local and statewide reports to measure congestion conditions of highway and arterial systems. This paper uses crowd-sourced anonymous probe-vehicle data to evaluate congestion duration at functionally obsolete bridge structures. The bridges selected were functionally obsolete due to poor ratings in their deck geometry as defined by the National Bridge Inventory (NBI) rating system. These deficiencies are based on a bridge’s traffic capacity as a function of its geometry and the average daily traffic (ADT). These conditions are directly expected to impact the speed and volume of traffic crossing over the bridge causing congestion. An evaluation of the travel times at bridge locations was conducted to determine if a measurable amount of congestion could be observed using probe-vehicle data. The methodologies presented in this paper were applied to 37 bridge structures in Burlington County, New Jersey. Approximately 35 million speed data records were analyzed for the 37 bridges to measure congestion. The congestion performance measures were compared with the NBI ratings to determine if congestion existed at the bridges as predicted by the NBI system. The comparison showed that a poor rating in deck geometry from the NBI system was not a strong indicator of congestion. The congestion evaluation methodologies presented in this paper were then combined with existing NBI structural ratings to demonstrate alternative bridge management strategies.

A centrifuge test was carried out to investigate the response of transit tunnels in saturated soils under internal blast loading. A similar test with dry soil was conducted beforehand as a comparison. The tests were carried out with a centrifugal acceleration of 50 g to simulate the effect of blast loading from 150-kg trinitrotoluene (TNT) inside a transit tunnel of 5-m diameter. Exploded bridgewire (EBW) charges were employed as the model explosives, and the model tunnel was simulated by thin-wall aluminum tube. The model tunnels were significantly damaged by the projectiles that were part of the EBW charges. Soil liquefaction occurred in saturated soil with 150 kg of TNT exploded at approximately the center of the tunnel.

Given the poor thermal comfort provided in many buildings, solutions have been sought that ally lower energy costs with a contribution to greater sustainability. Of these solutions, the thermal retrofitting of the outer envelope of buildings stands out, with various systems of façade insulation being devised such as ETICS (external thermal insulation composite system). Even though advantageous by comparison with other thermal retrofitting solutions, system integration in the façade needs to be minutely detailed. However, its integration in the facade is possible, provided that it meets the target objectives, including the improvement of thermal comfort. Taking the application of ETICS in façade rehabilitation as the starting point, with particular reference to residential buildings, this paper offers some proposals in the form of novel solutions for the architectural integration of the system based on current solutions, suggesting general design procedures. The architectural details of these solutions were the main object of the study and this paper presents some solutions for integration in the windows areas, which can prevent some very common errors frequently made nowadays. The degree of architectural integration of the solutions can vary according to four evaluation parameters: cost, durability, practicability and architectural integration. These parameters assume different values in the various proposed solutions, which is why there are several feasible solutions for each element of the facade.

Research has established that early attention to maintainability concerns during the design development and review stages provides a potential for delivering high levels of comfort to building occupants and reducing maintenance budgets. This paper seeks to identify and assess the set of electrical systems’ design defects that are attributed to a lack of the maintenance manager’s engagement with the design team. The research confirmed the importance of all the identified design defects based on the assessment of domain experts in the 13 public Saudi Arabian universities that operate and maintain considerable infrastructure in their campuses. The paper presents two sets of validated maintainability design review checklists for consideration by design professionals at the 60 and 90% design completion stages, in order to reduce the probability of occurrence of the identified defects. This paper serves to promote awareness among the various stakeholders in building projects about the earned benefits of maintenance managers providing their knowledge and experience of the operation and maintenance of existing facilities to design teams. It is of practical value to design professionals aiming to design maintainable, cost-effective building projects, and to have maintenance managers resolved to provide effective service to occupants and property owners.