Journal of Infrastructure Systems

One of the main activities in transportation infrastructure asset management is the allocation of available funds across infrastructure classes (e.g., pavements, bridges, signs) or programs (e.g., maintenance, construction). A methodology for allocating funds across transportation asset classes using multiattribute utility theory has been developed and is provided in this paper. This methodology can be used for performing trade-off analysis among asset classes where it is practical to consider potential shifts in funding from one class to another. The methodology was applied to a sample state highway network in Champaign County, Illinois. The sample highway network consists of pavements, bridges, culverts, signs, and intersections. Four funding allocation alternatives were evaluated using the developed methodology. The case study identified the funding allocation alternative that results in the lowest risk of infrastructure failure or poor performance (i.e., highest utility) from an experienced engineer standpoint. The utility analysis revealed that the decision maker in the case study is risk averse when managing infrastructure classes with the most potential to affect traffic safety and to be noticed by the public, such as bridges and intersections. The case study also revealed that the level of available funding and the level of infrastructure performance affect how the total funding is allocated among asset classes.

Office buildings are thought to be significant sources of energy use and emissions in industrialized countries, but quantitative assessments of all of the phases of the service life of office buildings are still quite rare. In order to enable environmentally conscious design and management, this paper presents life-cycle assessments of newly constructed European and U.S. office buildings from materials production through construction, use, and maintenance to end-of-life treatment. The significant environmental aspects indicate the dominance of the use phase in the quantified environmental categories, but draw attention to the importance of embedded materials and expected maintenance investments throughout the assumed 50-year service life, especially for particulate matter emissions. The relevance of the materials, construction, maintenance, and end-of-life phases relative to the use of buildings is expected to increase considerably as functional obsolescence of office buildings becomes more rapid, and complete reconstruction and reconfiguration become more frequent. By quantifying the energy use and environmental emissions of each life-cycle phase in more detail, the elements that cause significant emissions can be identified and targeted for improvement.

Economic modeling and risk analysis are important processes for the appraisal of infrastructure and revenue-generating projects such as build-operate-transfer (BOT) projects. These processes have been commonly implemented using spreadsheets in which the analyst would build several models to analyze a project under varying conditions and risk assumptions. For better efficiencies in building economic structures and evaluation of projects, the current paper defines “classifications” of estimating and cash flow methods, and develops a generalized model. A classification represents a particular domain—construction, revenues, financing, operation and maintenance, or risk analysis, for example—and holds the estimating methods of that domain. The basic building block behind the model structure is a work package/stream that would have its own properties and estimating methods by direct selection from the relevant classification. By integrating the building blocks together a project economic structure is built and various performance measures are formulated. The model was implemented in a prototype software system called Evaluator. A BOT highway project is used to show an application of the concepts and the generalized model.

This paper documents an investigation into the cause of structural distress (alligator cracking and deep rutting) found in a foamed-asphalt warranty project in Texas. This is a unique forensic study involving a warranty specification, where the contractor may or may not be liable for the cost of repairs, depending on the outcome of the study. Extensive field tests, including FWD, seismic, GPR, and DCP, were conducted. Laboratory tests were also done to determine gradation, moisture content, capillary action, and indirect tensile strength. Four trenches were opened to test each layer directly and to obtain samples for laboratory testing. Two of the trenches were located in distressed/failed areas, while two others were in intact areas. Based on this study, the forensic team concluded that the rutting and alligator cracking are associated with failure of the foamed asphalt base. Since the subgrade strength in the failed areas was similar to the intact areas, the subgrade strength could not have been the sole cause of the failure. The foamed asphalt base was found to be susceptible to moisture and exhibited a severe loss of strength when subjected to moisture. Thus, it is imperative to verify the moisture susceptibility during the design phase. Based on the findings of this study, the contractor did repair the failed section at his own expense.

Evaluation of the structural conditions and estimation of the remaining structural life of each pavement section are important considerations for prioritizing the maintenance needs of any highway network. Many highway agencies, where equipment for evaluation is not available and maintenance funds are limited, may not be able to carry out a detailed structural evaluation on individual pavement sections. An attempt has been made in this paper to develop a simple and cost effective model for structural evaluation of existing pavements. The important features of the model are (1) it can be executed with minimal amount of data, (2) the model is simple and does not require use of any costly equipment, and (3) the output of the model can be directly used for prioritization of maintenance needs at the network level. Two such models have been developed. The models are statistical and are derived from the long term pavement performance (LTPP) database developed by the U.S. Department of Transportation. The models have been validated and their predictions for remaining structural life (RSL) have been compared with the RSL obtained using the fatigue and rutting distress models of the Asphalt Institute. The results indicate that the proposed models are capable of predicting the RSL of existing pavements with reasonable accuracy and consistency, given that their primary use is in evaluating pavement structural conditions at the network level and for the purpose of prioritizing pavement sections for maintenance purposes.

Knowledge discovery in databases (KDD) has been applied in many different areas of study including DNA sequence analysis, pattern discovery, document classification, image recognition, and speech recognition. This paper presents the application of KDD in the analysis of a facility condition assessment (FCA) database. The FCA database contains information on facilities located at three campuses within a statewide university system. The case study utilizes cluster analysis for text mining. Cluster analysis is the grouping of objects that are similar within the same cluster and dissimilar to the other clusters. In this analysis, deficiency descriptions from a university’s FCA database are the objects being grouped together into clusters. Deficiency descriptions were gathered from 15 housing facilities and 15 academic facilities located at 3 campuses. The results show how some clusters of facility deficiencies are unique with respect to the type of facility and the influence of location on deficiencies of academic facilities. The paper begins with a presentation of background on clustering approaches in KDD. Next, a case study based on a higher education FCA database is presented. Last, the paper concludes by exploring other potential areas of application of the described clustering approach.

The problem of aging water pipes, resulting in leaks and breaks, affects municipalities worldwide. Mechanical failures of small-diameter pipes occur generally by circumferential cracking due to longitudinal bending. Most of the existing pipes are made of gray cast iron which exhibits different behavior in tension and compression. Hence, classic beam theory cannot be employed to determine pipe strength. A numerical strength evaluation method, as presented herein, is able to predict the strength of cast iron water pipes subjected to longitudinal bending. The method is affordable and simple to employ, and can be used effortlessly by water utility engineers.