Journal of Performance of Constructed Facilities

Progressive collapse resulting from local failures in accident events have caused many tragedies and loss of life in the past. The structural integrity and capacity to resist collapse are gradually improving as an essential requirement in structural design practice. As one of typical systems in industrial facilities and large-scale public buildings, a truss roof with low redundancy differs from a load-bearing wall and frame system. In this paper, the robustness of the truss structures is studied by both nonlinear static and dynamic analysis. The mechanism of internal force redistribution is studied and the importance of the mechanism affecting the subsequent failure process after the initial loss of the member is revealed. A method for identifying the sensitive and key element is put forth, and a Safety Assessment Method (SAM) based on linear static analysis procedure is proposed to evaluate the sensitivity index and key index of structural members. By this method, the vulnerability of a truss structure can be predicted and enhancement of the necessary countermeasures needed to prevent progressive collapse can be adopted.

This paper examines the performance of an overexcavated metro station in soft clay within Shanghai metropolitan area, in which there are many high-rise buildings and buried utility pipelines in the proximity. The excavation was supported by stiff concrete diaphragm walls braced by steel pipes. The measured performance included deflections of diaphragm walls, ground settlements, and settlements of the adjacent buildings and utility pipelines. On the basis of daily monitored data, the effects of overexcavation on wall deflections, deflection rates, and the locations in which the maximum wall deflections and the maximum wall deflection rates occurred were investigated. For those buildings in the proximity, the heavy high-rise steel-reinforced concrete buildings supported by deep foundations experienced limited uniform settlements, whereas the light brick buildings resting on shallow foundations experienced substantial total and differential settlements. For the adjacent utility pipelines, the excavation-induced settlements were relatively uniform.

Innovative architectural designs create new challenges for structural designers such as annoying vibrations because of the everyday occupant activities such as walking. The designer needs to predict the excitation levels to evaluate the structural response and assess the resulting vibrations for acceptable human exposure. This paper uses a long-cantilevered office building structure to study the floor response subjected to various measured and Fourier series-based forcing functions representing human walks suggested in standards, design guides, and research studies. In addition, the vibration evaluation parameters proposed by several standards are computed and compared by using computer analyses and field measurements. For the majority of the cases studied in this paper, use of the Fourier series-based forcing functions resulted in an overestimation of the structural response. In addition, the in-place marching excitations to represent walking recommended in some design guides can grossly overestimate the structural response. The computed vibration evaluation parameters using the computer analyses and field measurements also had moderate differences with one another when the walk excited the structure’s first mode of vibration.

Building commissioning has been gaining momentum and awareness within the building industry as a comprehensive quality assurance process that can be used throughout the buildings life cycle to ensure that the needs and requirements the owner has for the building are met. Although building commissioning is gaining momentum it is still far away from being viewed as normal practice within the building industry. Of the countries that are the closest to succeeding in making building commissioning normal practice, the United States is the leader. To decrease the time it will take for commissioning to become normal practice in countries were commissioning is taking its first steps or has not yet been used, it would be beneficial to learn from the leading nations on how they have implemented commissioning. Because the United States is among the leading nations in implementing commissioning, there is a lot that can be learned from on how that process has evolved and all the effort that has been put into research on building commissioning. This article investigates how the commissioning process is undertaken at a leading commissioning providing consulting company in Denmark, and presents a case study with a comparison between two shopping malls out of which one has not been through a commissioning process, while the other has. The benefits of commissioning are outlined and proposals for how the process can be improved in the Danish consulting company compared to the well-established ASHRAE 0-2005 guideline. Finally, the article discusses and concludes what the future steps for commissioning in a country like Denmark should be based on how commissioning has evolved in the United States.

Construction projects often suffer from material unavailability, which results in failure to meet set schedules. Subjective judgment is commonly used to describe the level of material availability for such projects. Construction experts often state their opinions using linguistic expressions that describe the likelihood of project delay. Fuzzy logic can be used to describe the relationship between material availability and the likelihood of project delay. This paper applies fuzzy modus ponens deduction techniques to model material availability and related project delay by incorporating Baldwin’s rotational fuzzy-set models. This deduction technique consists of three processes: the Truth Functional Modification (TFM), Inverse Truth Functional Modification (ITFM), and Lukasiewicz Implication Rule (LIR). The TFM finds the truth of a fuzzy-set, the ITFM is the inverse of TFM, and the LIR obtains the truth of an implication relation. This study presents a model that can be used to simulate material availability level and its impact on project schedule. Validation of the model showed between good and very good overall appearance and suggests that the model is applicable to the construction industry.

Two specimen series [limited seismic (LS) and nonseismic (NS)] were subjected to quasistatic loadings to evaluate the residual axial capacity of blast-damaged reinforced concrete (RC) columns. A validated numerical model was used to predict the residual lateral deflection of RC columns subjected to an explosive attack. Three hydraulic actuators were installed horizontally to reproduce the target residual lateral deflection as predicted through this numerical model. Another two hydraulic actuators were installed vertically to apply the axial load and measure the residual axial capacity of the damaged columns. The effects of parameters such as axial loading and the transverse reinforcement ratio are investigated through this study. The results obtained from the experimental study showed the improved performance that LS detailing provided to RC columns to resist blast or lateral loads. This subsequently led columns detailed with a higher transverse reinforcement ratio to have an increased residual axial capacity when laterally damaged, as compared with the NS detailed specimens. Axial load (service load) on the columns was also found to affect the residual deflection profile and residual axial capacity of the columns after the specified blast event. The validity range of a previously published function to determine blast-damaged residual axial capacity of RC columns is refined through the results obtained.

This paper investigates new damage detection method for bridges to ensure their safety. The idea of using displacement data of two symmetrical points for multiple damage detection is presented for the first time. After introducing the concept of Equivalent Element, a novel index termed as “Symmetrical Displacement Difference Index (SDDI),” is proposed. The displacement under static load is used for constructing the new index. Then the relationship between the local flexural stiffness change caused by damage and SDDI value is generated. In application, SDDI values can be plotted after the measurement of displacement. The relative changes between the intact state and the damage state in the curve shapes can be used to indicate the position of damage. This new damage detection method based on SDDI is flexible enough to be applied to real-world bridges with inherent random uncertainty and actual support condition. Numerical and experimental examples have been conducted to examine the suitability of the method. This paper provides a simple, convenient, cost-effective, and nondestructive damage detection method for bridges.

Bridge management systems generally rely on the accurate interpretation of findings determined from planned bridge inspections. Bridge inspections typically focus on the overall condition of the bridge and the condition of its components. During a recent bridge inspection with multinational team, it was observed that the overall grade of a bridge could be significantly high, even though it contains one or more failing subcomponents. Over the years, it has been observed that failure of a deteriorated component could result in catastrophic failure of bridges. The focus of this paper is to develop an analytical method to interpret the bridge inspection data in such a way that failing components can be identified with reasonable accuracy for a bridge with a good inspection grade in general. The proposed mathematical model can be used in bridge management systems and in maintenance programs for bridge owners to identify immediate rehabilitation needs.

Scouring around a bridge foundation is a problem of much concern to civil engineers. The main purpose of this paper is to gain more understanding of the effect of scouring around the pile on the lateral capacity of the piles embedded in sandy soil. Factors such as soil stiffness, pile head fixity, and pile slenderness ratio ($L/B$) were studied to show their effects on the variation of the percentage decrease of lateral load capacity (PDC) due to scouring near an isolated pile. The results indicate that the PDC value reaches almost 50% when the scour depth reaches 1.3 to 2.4 times the pile diameter, and that piles with a fixed head are more capable of resisting lateral load loss. Furthermore, the PDC values remain almost constant after the pile slenderness ratio is greater than 10. Hence, the decrease in lateral load due to scouring of the soil will be more serious for short piles.

This paper presents the fatigue behavior of an integrated crosstie system for an Advanced Rapid Transit (ART). The crosstie system consists of steel base plates welded to a hollow structural section, and a concrete guideway slab. The steel-wheeled ART is operated by linear induction motors (LIM) and provides a unique load configuration to the crosstie system, including electromagnetic force and gravity load. To absorb dynamic effects from the ART, elastomeric pads are placed under the base plates. A three-dimensional finite element analysis is conducted to examine the fatigue performance of the crosstie, on the basis of cumulative damage theory. The study focuses on stress progression, displacements, and stress concentrations in the crosstie system subjected to fatigue load of up to three million cycles. The effect of pad deterioration on the fatigue behavior of the crosstie is evaluated. Design recommendations to improve the sustainability of the crosstie system are discussed.

A stretch of State Highway (SH) 6 in Texas has been experiencing poor ride quality problems caused by continuous pavement swelling and heaving. Because of this, the Texas Department of Transportation (TxDOT) Waco District annually spent hundreds of thousands of dollars to overlay the pavement to keep it smooth. This study is motivated to identify the root causes and solutions to the critical problem. During the forensic study, a systematic approach is employed, which includes nondestructive and destructive tests. On the basis of the overall test results, it is revealed that the problem was initiated within the lower portion of the pavement structure (i.e., subgrade) rather than in the upper pavement structure (i.e., asphalt concrete and flexible base). It was further found that the major factors contributing to the subgrade problem include (1) swelling soils, (2) water penetrating into the expansive clay soils, (3) high organics content in the soil, (4) loss of strength of the lime stabilized layer, and (5) high levels of sulfates in the soils. Performance surveys of various potential treatments for remediating the problem associated with swelling subgrade soil and increased moisture were conducted. These performance histories provide input and guidance for the selection of the pavement rehabilitation strategies. On the basis of the past performance histories, a variety of short-term and long-term strategies were recommended to the Waco District office for solving the problem.

Condition assessment is an integral component in any infrastructure asset management system. Without condition information, asset managers lack the ability to make appropriate decisions regarding needed maintenance, rehabilitation, and replacement of infrastructure. Existing and emerging technologies for assessing the condition of water and sewer pipes provide a better picture of the state of these buried assets. Unfortunately, many of these technologies are costly and provide results that are not always highly reliable. This paper presents a methodology to assist asset managers in balancing the value of information revealed by a condition assessment technology with the cost of obtaining this information. The paper describes the computational platform of the developed methodology and focuses primarily on the optimization process that utilizes the partially observable Markov decision process (POMDP) and genetic algorithms. This policy determines the most appropriate condition assessment technology and interval between inspections. The developed methodology takes into consideration direct and indirect costs of infrastructure failure. Optimization models are developed at both the asset and network levels. A case study of the water distribution network for the city of Hamilton, Canada, is presented to demonstrate the use and capabilities of the developed methodology. At the asset level, results allow the asset manager to select the most suitable condition assessment technology and inspection interval for a particular pipe. At the network level, results enable the proper allocation of a condition assessment budget across all pipes in the system.

To fulfill the navigation development plan of the Hu-Jia-Shen Channel located on the eastern coast of China, it is necessary to upgrade its width and clearance height. The Qifeng Bridge, an arch bridge over the channel, is required to be raised by 2.5 m using the integral lifting method. In this paper, the operation principles of the hydraulic jack system, the composition of the supporting structures, and the lifting process of the bridge are presented. To verify the proposed procedures adopted in this project, a 3-dimensional finite-element method (FEM) model, incorporating a bridge-capping beam of main span and a supporting girder, is established to analyze the contact behavior and stress distribution characteristics between the beam and supporting girder. The induced stresses in the superstructure and supporting structures are also monitored and analyzed.