Journal of Performance of Constructed Facilities

This paper explores the current recommended measures for assessing vibration serviceability in building structures and the recommendations for relating these vibration measures to levels of perception and expected occupant reactions. Two of these assessment measures, the maximum transient vibration value and vibration dose value, are discussed with respect to serviceability in stadium structures. The results of the monitoring and assessment of three stadium structures during several events are presented and these results indicate that the current recommendations are overly conservative in assessing occupant perception. Recommendations for vibration dose levels that are more consistent with the evaluation of events monitored in stadium structures are proposed.

Steel corrosion in reinforced concrete (RC) structures leads to change of steel mechanical properties, longitudinal cracking in the concrete cover, and other related effects that weaken the serviceability and load capacity of the composites. It is therefore extremely important to have methods targeted to the evaluation of the structural damage induced by corrosion for estimating the residual load capacity of a structure, and then for inspection procedures and strengthening the maintenance interventions. This paper presents a simplified methodology capable of providing estimates of the residual life of corroded RC beams. The proposed method uses damaged material properties, and accounts for the length of partial corrosion and the amount of corrosion, concrete loss and change of bond strength within this specified length. A comparison of the model predictions with the experimental results published in the literature shows the validity of the model. It is also concluded that the ultimate flexural moment of corroded RC beam will not significantly influenced by the partially corroded or unbonded length and the bond characteristics over this partial length as long as the tensile steel of the beam can reach its yield strength. In addition, although complete loss of bond over the partial length is assumed to asses the residual strength of corrosion-damaged RC beam, neglecting the influence of bond strength within the corroded length may lead to underestimate the ultimate flexural capacity of the damaged beam, especially when the corrosion level of tensile steel of the RC beam is not very high.

Process capability (PC) characterizes the variation in a parameter of a process’s output. From a constructability perspective, investigating PCs for geometric variation is important when specifying tolerances for all construction processes. This paper investigates a case involving soldier piles used in a slurry wall and compares the design specified tolerances to as-built field data. As with other cases investigated by the writers covering many major construction processes, this case also shows that designers specify tolerances based on tacit estimates of variation limits, not PCs. Consequently, the PCs consistently exceed the design specified tolerances, preventing the possibility of proper tolerance management and causing problems to manifest during construction. The writers conclude that variation estimates are an inaccurate basis for specifying tolerances and instead should be based on PCs.

Engineering services provided by one of the writers to property owners, insurance companies, attorneys, and others have resulted in a compilation of case studies, based on more than 1,000 site inspections, suitable to generate a database regarding various aspects of building performance. The scope of those services typically included identifying the cause and origin of damage to residential and commercial structures, as well as an estimation of the magnitude of damage sustained by those structures. The majority of those damaged structures was located in proximity to a coastal region and experienced recent exposure to a storm or other weather event. Compilation of data from those case studies allowed identification and ranking of the occurrence of chronic building problems. It has become apparent that building-related deficiencies often exist as a common feature in similar structures. Some of those recurring deficiencies could be eliminated with alternate building design, better construction practices, or proper routine maintenance procedures. Where applicable, proposed remedial solutions are presented for specific building deficiencies or problems identified.

The concrete deck of a 340-m long composite bridge having a general slope of 6.5% was built by increments of 20 m. Forming and concreting were done behind the upper abutment. Increments were successively pushed over the steel girders with cast iron shoes inserted between concrete and steel at regular intervals. As the third increment was in place, it was noticed that the concrete ribbon was slightly curved and laying somewhat eccentrically over the girders. The deformation of the steel flanges induced transverse weight components. Moreover, launching is always accompanied by dynamical effects, which were not correctly understood. As the 10th increment was being pushed, an arresting plate holding the steel structure at the upper abutment in the longitudinal direction failed and transverse weight components helped setting the deck in motion, which then began sliding.

Damage often causes changes in the dynamic characteristics of a structure such as frequencies and mode shapes. Vibration-based damage identification techniques utilize the changes in the dynamic characteristics of a structure to determine the location and extent of damage in the structure. Such techniques are applied in this study to the Crowchild Bridge, a steel-free deck continuous bridge located in western Canada. While the numerical models of the bridge are correlated with the measured dynamic characteristics, computer simulation is used to study the identification of a number of different damage patterns, and the effects of measurement errors and incomplete mode shapes on the quality of results are evaluated. The effectiveness of some selected damage identification techniques is examined; the potential difficulties in identifying the damage are outlined; and areas of further research are suggested. A three-dimensional finite-element model and a simple two-dimensional girder model of the bridge have been constructed to study the usefulness of the selected damage identification methods. Another promising damage detection method proposed here is based on the application of neural networks that combines a vibration-based method.

Shoulder rutting and pavement edge drop-offs are common performance problems associated with granular shoulders. Being hazardous to drivers and difficult to maintain, such problems require more attention. Shoulder rutting is primarily caused by bearing capacity failure of the subgrade, whereas edge drop-offs develop by surface runoff erosion, vehicle-induced wind erosion, or vehicle off-tracking. Evaluating the performance of several granular shoulders in Iowa revealed that 2/3 of the inspected sections had an edge drop-off greater than 38 mm, while 40% had a subgrade layer with a California bearing ratio less than 10. A high-speed camera was used to study vehicle tire-aggregate interaction upon off-tracking. Off-tracking was found to elevate and displace aggregate particles away from the pavement edge. Based on these findings, six test sections were stabilized and monitored. The granular layer of four sections was stabilized using polymer emulsion, foamed asphalt, Portland cement, and soybean oil. The soft subgrade layer of two sections was stabilized using Class C fly ash and biaxial geogrid. This paper discusses granular shoulder performance problems, the repair and monitoring of six stabilized test sections, and recommendations to improve the long-term performance of granular shoulders.

The need of immediate supportive measures for sustainability of municipal infrastructures calls for better understanding of the behavior of various infrastructure network systems and their components. This paper presents a study which uses artificial neural networks to investigate the importance and influence of certain characteristics of sewer pipes upon their structural performance, expressed in terms of condition rating. In this study, back propagation and probabilistic neural network (NN) models were developed and validated. The data used in the development of these models were provided by the municipality of Pierrefonds, Quebec. It comprised of parameters related to sewer pipelines, pipe diameter, buried depth/cover, bedding material, pipe material, pipeline length, age, and closed circuit television (CCTV) based structural condition rating. The first six parameters are the independent variables of the models whereas CCTV based condition rating for these pipes is the dependent variable (i.e., the output of the models). The developed NN models were used to rank the parameters, in order of their importance/influence on pipe condition. It was found that, among the studied parameters, material attributes have highest influence on pipe structural condition, respectively, followed by the geometric and physical attribute group. Sensitivity analysis was then performed to simulate the structural condition of a pipe at a range of values of each input parameters. Results of sensitivity analysis describe the nature and degree of the influence of each parameter on pipe structural condition. The developed models are expected to benefit academics and practitioners (municipal engineers, consultants, and contractors) to prioritize inspection and rehabilitation plans for existing sewer mains.

While facility design is increasingly playing a role addressing strategic organizational objectives, issues pertaining to facility maintenance have typically been left out of the decision-making process. Reasons include the traditional disconnection between facility design and facility maintenance, mainly originating from the lack of a modality to meaningfully represent facility maintenance information during design decision making. This paper discusses two sets of facility maintenance indicators that have the potential to bridge this traditional divide. The objective of this paper is threefold: (1) to illustrate how maintenance performance indicators can support higher-level decision making; (2) to explain how the methodology could be mapped across building sectors; and (3) to show how facility maintenance could play a crucial role in informing strategic decision making. Two types of indicators are introduced based on: (1) normative models in biophysics and physiology and (2) empiricist models of environment-behavior studies. Using examples from hospital, courthouse, and office building design, the paper articulates the manner in which facility performance indicators could be developed and used to support organizational strategic decision making. The paper demonstrates that facility maintenance indicators could be developed for all types of buildings and could be meaningfully represented for consideration during strategic decision making. Moreover, using an example of a healthcare setting, the paper emphasizes how facility maintenance strategies have an impact on higher-level organizational objectives, and vice versa, thereby underscoring the importance to consider maintenance performance during strategic decision making. The paper shows how the two sets of key performance indicators—the hard and the soft—are designed to address different scales of decision making, thereby allowing facility maintenance performance to be considered at all phases of a procurement cycle.

The Cabin John Bridge (CJB), located just outside Washington, D.C., is a masonry arch with a central angle of 110°, an intrados radius of 40.9 m (134 ft), and a span of 67 m (220 ft). Construction of the bridge began in 1857 but was not completed until late in 1863 because of suspensions due to lack of appropriations and the Civil War. The CJB is part of the Washington Aqueduct (WA) and is still the longest single-span masonry arch in the United States. The bridge was designated a National Historic Civil Engineering Landmark by the ASCE in 1972. The paper provides context for the bridge design and explains the construction technologies that were used. In the process, French and British influences on American masonry arch design practices at mid-19th century are revealed. The respective roles of Captain Montgomery C. Meigs, the chief engineer of the WA, and Alfred Landon Rives, his assistant engineer, are critically assessed. The paper provides, for the first time, relevant facts on Rives’ education and engineering career. The performance of the bridge over 145 years is reviewed and discussed.