Journal of Performance of Constructed Facilities

Facilities management (FM) has witnessed a rapid development since its nascence in 1980s. Following its development, the concept of involving FM specialists in building design, simply called early FM involvement, has received an increasing attention from practitioners and researchers in the last decade, which makes it possible to incorporate FM knowledge and experience into the design process. This study investigates the involvement through a series of expert interviews in the United Kingdom. The objective of this study is to get a more thorough understanding of early FM involvement practice. The analysis of interview results shows that it is very important to address a variety of potential problems, such as the lack of operability, maintainability, and serviceability, by applying FM expertise to design decision-making. Early FM involvement in design is found to be particularly useful for the improvement of cost efficiency and effectiveness from a long-term perspective. Although it has received wide recognition today, it still encounters resistance in practice. To ensure its success, there is a need for all the key stakeholders, such as project clients, designers, and FM providers, to continue to make intense efforts.

Experimental research on imposed deformation is generally conducted on small-scale laboratory experiments. The attractiveness of field research lies in the possibility to compare results obtained from full-scale structures to theoretical predictions. Unfortunately, measurements obtained from real structures are rarely described in literature. The structural response of integral edifices depends significantly on stiffness changes and constraints. The New Airport Terminal Barajas in Madrid, Spain provides investigators with large integral modules, partially post-tensioned concrete frames, cast monolithically over three floor levels with an overall length of approximately 80 m. The field campaign described in this article explains the instrumentation of one of these frames, focusing on the influence of imposed deformations such as creep, shrinkage, and temperature. The applied monitoring equipment included embedded strain gauges, thermocouples, hand-held mechanical strain gauge measurements, and simple displacement measurements. Data were collected throughout construction and during two years of service. A complete data range of five years is presented and analyzed. Using a simple approach, the results are compared to predict the long-term shortening of this concrete structure. Both analytical and experimental results are discussed.

The long-term behavior of concrete structures has shown that their main cause of distress is reinforcement corrosion. One of the most punishing exposure conditions for concrete is a marine environment such as that found in the Persian Gulf. Reinforcement corrosion from diffusion of chloride ions is the main mechanism for deterioration under such conditions; it is found that chloride penetration and chloride-induced reinforcement corrosion rates can be very high, often leading to a reduced service life. This paper presents results of a study performed on a 40-year-old RC jetty structure in the Mahshahr Petrochemical Special Zone, Persian Gulf region that had suffered extensive deterioration from chloride-induced corrosion. Based on visual inspection as well as in situ and laboratory tests, it was strongly evident that the structure had not been designed and built under sufficient qualitative specifications.

A building is subjected to progressive collapse when a primary vertical structural element fails, resulting in the failure of adjoining structural elements, which cause further structural failure, leading eventually to partial or total collapse of the structure. The failure of a primary vertical support might occur because of extreme loadings such as a bomb explosion in a terrorist attack, a car colliding with supports in a parking garage, an accidental explosion of explosive materials, or a severe earthquake. Different design codes address the progressive collapse of structures attributable to the sudden loss of a main vertical support such as the General Services Administration (GSA) code and the Unified Facilities Criteria (UFC). The alternative path method (APM) is the main analysis method for evaluating the hazard of progressive collapse in the two codes. The APM requires that the structure be capable of bridging over a missing structural element, with the resulting extent of damage being localized. In the current study, a progressive collapse assessment according to the GSA code is carried out for a typical ten-story RC-framed structure. The structure is designed according to the building code requirements for structural concrete. Fully nonlinear dynamic analysis for the structure is carried out using the applied-element method (AEM). According to the GSA code, a primary vertical structural element is removed, and the collapse area is investigated. The investigated cases include the removal of a corner column, an edge column, an edge shear wall, internal columns, an internal shear wall, and a corner shear wall. The numerical analysis showed that, for an economic design, the analysis should consider slabs and cannot be simplified into a two- or three-dimensional frame analysis. Neglecting the slabs in the progressive collapse analysis is a very conservative approach that may lead to uneconomic design. The RC structures designed according to American Concrete Institute guidelines met the GSA limits and were found to have a low potential for progressive collapse.

Modeling and numerical simulation of foam sandwich panels subjected to impulsive loading are presented. The sandwich panels consist of steel sheets at front and back with two varieties of foam cores in between. Stiffeners are provided at the back sheet for improved response. The dynamic response of the stiffened steel plate (SSP), sandwich foam panel (SFP), and stiffened sandwich foam panel (SSFP) are compared. The foam material modeling accounts for elastic-plastic behavior with volumetric hardening. The finite element–based numerical simulation for dynamic analysis is performed using a combination of shell and solid elements for sheets and foam, respectively. Central point displacements caused from the impulsive load of peak pressure of 0.7 MPa and lasting for 15 ms applied uniformly to the sandwich panels are studied. The analysis is carried out with an objective of understanding the effects of foam thickness, type of foam, and the stiffener configurations. The results obtained indicate that the SSFP considerably increase the resistance to impulsive loading compared with the SSP and SFP.

In this paper, the impact action of a flood on rural mountain buildings is systematically studied. First, based on the one-dimensional Saint-Venant water equation explicit-difference scheme, a new explicit-difference scheme is deduced to establish the evolutionary routing model of a flood. A computational formula about the impact loading of the flood model is deduced. Secondly, an impact experiment of a flood on buildings is carried out in a large wave-current tank. The heights of the water are 0.6, 0.9, and 1.2 m, and the distances between the building and floodgate are 3, 6, and 9 m, respectively. The model scale of the buildings is 1:6, and three buildings with different ratios of holes are designed to simulate the buildings in countries and villages. Based on the experimental results, the effects of the heights of the water, the distances between buildings and floodgates, and the ratios of holes on the impacting pressure are investigated. The numerical results are compared with the experimental results, and the distribution of impact loading is also studied. Finally, the rural building is analyzed numerically to investigate the destruction of the building because of the flood impact. The rural building is dissected into 7,950 eight-node block elements and 4,098 Goodman elements to simulate the brick and mortar, respectively. The stress, the displacement, and the failure process of the rural buildings are studied.

This paper presents an expert system to support the inspection and diagnosis of wood applied as a floor covering [wood flooring (WF)]. The defects that may affect WF along with their probable causes are classified in this system. The inspection system also embraces the correlation matrices between defects and between defects and probable causes, the classification of the diagnosis methods, and the repair techniques suitable for each WF defect. This paper also includes an example of an individual defect file containing a complete characterization and the most suitable diagnosis methods and repair techniques. This inspection system was validated through standard inspections of 90 WFs applied indoors and eight applied in exterior areas, in a total of 35 buildings.

The primary objective of structural health monitoring (SHM) is to determine whether a structure is performing as expected or if there is any anomaly in its behavior compared with the normal condition. It is also useful in detecting the existence, location, and severity of damage. Vibration-based damage detection methods are very frequently used in SHM. However, because of complicated features of real-life structures, there are uncertainties involved in the key input parameters (e.g., measured frequencies and mode shape data), which affect the performance of these methods. If vibration-based methods are incorporated with semianalytical methods, such as statistical pattern recognition techniques, better accuracy can result in structural health assessment. This paper explores the statistical pattern recognition techniques for damage detection and/or degradation in structures. A case study, the Portage Creek Bridge in Victoria, British Columbia, Canada, has been used. The following two approaches of the statistical pattern recognition techniques have been used: statistical pattern comparison and statistical model development. After filtering and normalizing the data obtained from the SHM system installed in the bridge, damage sensitive features have been extracted by autoregressive modeling of the time series data. Both idle and excited states of the bridge are considered in this case. From the statistical analysis of the strain and acceleration data, although the bridge is in a good condition, there is a small but steady deterioration in its performance. The study also demonstrates the feasibility of the statistical pattern recognition techniques in assessing the structural condition of a practical structure.

This paper presents a comparison of two live-load tests performed on a posttensioned, box-girder bridge. The initial live-load test was performed more than 20 years before the most recent test. Strain gauges were placed at the same location for both tests. In each case, the bridge was subjected to nearly identical loads so that changes in strain could be correlated as a heavy truck drove across the instrumented bridge. A comparison of the bridge behavior based on the two load tests is presented. The changes in recorded strain were also used to validate a detailed finite-element (FE) model using primarily shell elements. From this calibrated FE model, the live-load distribution factors for moment were obtained. These factors were used to calculate both the inventory and operating rating factors of the bridge. These values were compared with those calculated in accordance to the AASHTO LRFD specifications for distribution factors. It was found that the rating factors could be increased by 26% because of the partial fixity caused by the integral abutments.

This study aims to determine a cost-effective design for mitigating the dynamic response of multispan tall-pier bridges subjected to longitudinal seismic excitation. Time history solutions are provided for a dynamic system of discrete and finite elements which models sliding friction, collision contact, and nonlinear behaviors. The approach involves conducting vulnerability tests on parametric models comprising various parameters for piers, bearings, and backfill soils. The bridge prototype as evolved combines the use of adapted rubber bearings and cemented backfill. It satisfied specified performance criteria without structural damage under six strong motions from the Kobe and Chi-Chi earthquakes. The margins of safety and serviceability were ensured by a statistical analysis considering the uncertainty of backfill and bearing properties.

Failure studies are important for engineering practices. Lessons learned from failures provide valuable information to help ensure future success. This paper explores the causes of failure in mechanically stabilized earth (MSE) structures reinforced with geosynthetics. Nineteen cases of MSE failure are carefully examined and quantitatively studied. The results of the forensic study indicate that intense rainfall is the primary natural cause for the observed MSE failures. Incorrect engineering practices are also implicated in the MSE malfunctions, and the study determines that inadequate project planning and site exploration and poor construction quality are the most important reasons for human-caused failures. In addition, the study also shows that MSE failures occur because of a lack of essential training in traditional slope stability analysis, rather than from a deficiency in MSE expertise. The results of this study offer useful lessons to MSE professionals for not only improving their engineering practices but also ensuring more reliable MSE structures in the future.

A combined ground-improvement method has recently been adopted for embankments on soft soil that involves the use of both deep mixed (DM) columns and prefabricated vertical drains (PVDs) to increase the bearing capacity and accelerate the consolidation of the soft soil. A well-instrumented embankment was constructed in a field using this ground-improvement method to verify its performance. Three- (3D) and two-dimensional (2D) finite-element analyses were conducted to evaluate the performance of an embankment constructed over soft soil improved by the DM columns and PVDs. In the 2D analysis, a plane-strain conversion method was used to simulate the 3D condition. The finite-element software ABAQUS was used for these analyses. The computed settlements, excess pore-water pressure, load transfer from the surrounding soil to the columns, and lateral displacements in both analyses are compared with the field data, and good agreement was found between the computed and measured data. The field and numerical results show that the DM columns enhanced the stability of the embankment over soft soil, whereas the PVDs accelerated consolidation of the soft soil.

Water hammer is an unsteady hydraulic problem commonly found in closed conduits of hydropower plants, water distribution networks, and liquid pipeline systems. Because of either a malfunction of a system or inadequate operation conditions, a pipeline may collapse or burst erratically, resulting in substantial damages and human loss in some cases. Therefore, it is crucial that engineers design and/or analyze projects with reliable computing methods for all foreseeable operation situations. In this paper, transient flow situations in run-of-river plants are investigated for various operation conditions such as load rejection, load acceptance, and instant load rejection. A computer program using the method of characteristics is used in two case studies having Pelton and Francis turbines, respectively. On the basis of the field data of the plants, their computational models are set up, and resulting transient pressures are computed and compared with available measured pressures. Comparisons indicate that the mathematical model predicts the measured pressures closely for all simulations.

Asset management provides a managerial decision-making framework for public agencies to monitor, evaluate, and make informed decisions about how to best maintain vital civil infrastructure assets. Among many steps required for implementing asset management, developing an accurate deterioration model is one of the key components because it helps infrastructure agencies predict remaining asset life. The accuracy of deterioration models highly depends on the quality of input data and the computational technique used in data analysis. Among many options of computational techniques, a decision tree offers the combination of visual representation and sound statistical background. The visual representation enables the decision maker to identify the relationship and interdependencies of each decision and formulate an appropriate prediction. This study developed a decision tree–based deterioration model for sewer pipes. The performance of the new model is then compared with conventional regression- and neural networks–based models that are also developed using the same data sets. The result shows that the decision tree outperformed other techniques in terms of accuracy (error rate). The paper also discusses different deterioration patterns of different categories of pipes.

Canadian municipalities spend $12–15 billion annually on infrastructure, but it does not seem to be enough. Similarly, it is reported in the United States that the cost of upgrading the water system would cost US $77 billion over the next 20 years. The available annual funds to water authorities for rehabilitating these assets are only a small fraction of the total replacement cost of a water system infrastructure. Therefore, there is an essential need to develop a fund allocation model to prioritize the allocation of funds (budget) to candidate projects in water mains. The model is developed using an integrated analytic hierarchy process and multiattribute utility theory based on the judgment of municipal experts across Canada and the United States. It considers several factors and their effect on prioritizing candidate water mains (i.e., pipe type, age, diameter, C factor, break rate, number of breaks, population served, water quality, and risk of misallocation). Qualitative data are collected from practitioners across North America, and water network data are collected from two main municipalities in Canada. The developed model is relevant to researchers and practitioners (municipal engineers, consultants, and contractors) to support decisions and prioritize water mains for fund allocation.

The ample framework to maintain infrastructure remains the continuous challenge in efficiently carrying out municipal duties. In North America, aging municipal infrastructure has reached the breaking point. This results in a large excess of infrastructure rehabilitation activities and cost escalation. Life-cycle cost (LCC) analysis, which can effectively deal with data vagueness and judgmental appraisal, is essential to evaluate various alternatives of infrastructure rehabilitation, particularly for sewers. Therefore, the objective of the present research is to develop LCC models using fuzzy and simulation approaches that deal with vague, imprecise, qualitative, linguistic, or incomplete data. Deterioration and cost data are collected for two sewer materials—PVC and concrete—with diameter ranges from 150 to 600 mm. The developed LCC models, with the help of an automated Microsoft Excel–based program, are utilized to select the best rehabilitation alternatives/scenarios. Results show that open-trench/sleeve, slip-lining, and pipe-bursting scenarios have the lowest LCC in spot-repair, renovation, and replacement categories, respectively. The developed models help academics and practitioners (for example, municipal engineers) plan suitable new installation/rehabilitation programs and their associated costs to avoid any unpleasant surprises.

Construction activities bring many changes to the development areas and can create unexpected engineering problems. Accurate identification and successful resolution of those problems sometimes requires the incorporation of geochemical methods in geotechnical investigations related to preconstruction conditions. Geochemical analysis should also be added to the forensic engineer’s toolbox to understand changes that might have occurred or might be occurring in a site’s geologic, hydrologic, and loading conditions. Correct evaluation and understanding of geochemical processes at the problem sites can help protect the undamaged structures or ensure the use of the most efficient and cost effective methods of repair.