Journal of Infrastructure Systems

Statistical models of infrastructure facility deterioration are typically estimated using panel data sets of in-service facilities. For example, biannual ratings of bridges have been used to develop discrete models of component deterioration by a number of researchers. Unfortunately, these models have not accounted for the presence of heterogeneity in the panel data, which may lead to biased coefficient estimates. Furthermore, researchers have usually imposed a Markovian specification in the development of such models, implying that the probabilistic deterioration in a given period is independent of history. This assumption may be unrealistic for some types of facilities in which early stress initiation leads to accelerated deterioration in later stages of their lives. In this paper, we adopt a random-effects specification to control for heterogeneity in a probit model of bridge-deck deterioration and extend the model to investigate the presence of state dependence. The proposed model yields improved results in comparison with a simple probit model and provides evidence that is inconsistent with the Markovian assumption in bridge-deck deterioration. An implication of this study is that both heterogeneity and state dependence may need to be accounted for in developing probabilistic infrastructure deterioration models.

The relevance and important implications of regulations governing the sizes and weights of heavy vehicles in highway infrastructure management are presented. A procedure for evaluating the infrastructure impacts, trucking productivity, and highway cost-allocation implications of alternative truck weight limits and enforcement options is presented. The procedure uses a weight-prediction methodology that resolves some major uncertainties from the regulatory standpoint respecting input variables required to provide the technical basis to support policy regulatory and infrastructure management decisions. The regulations represent the core of transport policies relating to trucking productivity, infrastructure provision, and management. Any revisions in the size and weight limits are reflected in truck fleet, operating weights, and volumes, which in turn affect the infrastructure geometric requirements, loadings, maintenance, and rehabilitation intervention levels. The proposed evaluation approach allows regulatory and weight-control policies that are compatible with the existing infrastructure capabilities to be developed.

A capacity-weighted reliability surface is suggested as a tool to assess the condition of deteriorating water supply infrastructure. A method is developed for calculating the spatial variation in reliability throughout a water distribution network. The method considers the reliability to meet demands at nodes to depend on the reliability and hydraulic capacity of all the network elements leading from the sources. Using a measure of network connectivity, point values of the reliability of water supply at demand nodes are calculated. An efficient algorithm is developed to adjust these point values in order to account for the carrying capacities of the components linking the source of water to the demand points. The adjusted values are then contoured to define the reliability surface. The surface may be used as an aid for prioritizing the maintenance and rehabilitation of the water distribution network.

In 1988, the National Council on Public Works Improvement (NCPWI) issued a report, which made various recommendations with respect to national infrastructure policy. The recommendations included a commitment to double current spending, rational capital budgeting at the federal level, and incentives for better financing and management of public works investments. NCPWI's report was especially notable because Congress created the commission and asked for its views. The present paper analyzes Congressional legislation submitted since the issuance of the report and assesses the degree to which Congress responded to the guidance contained within the report. The analysis shows that there were many bills submitted that picked up the recommendations, but none of these bills passed, indicating a lack of national consensus around these issues. The only major bill that did pass and that did contain some of the ideas pondered by NCPWI was the Intermodal Surface Transportation Efficiency Act (ISTEA), indicating that while transportation has coherence as a national concern, infrastructure does not yet have that full-blown identity at the Congressional level.

In existing bridge management systems, the information on one stage in the life cycle of a bridge is not efficiently used in other stages, which results in much waste in time and effort. In this paper, a new type of bridge life-cycle management system is developed to overcome this problem. The system integrates geographic information, design data, inspection and maintenance data, earthquake data, and image data in a user-friendly environment. These improvements make it possible to use the system during the entire bridge life cycle, from the planning stage to the demolition stage, as discussed here. Several applications of this system are discussed, which include location selection, condition assessment, maintenance plan optimization, and spatial retrieval.

The University of Texas at Austin conducted a study for the City of Austin to evaluate the performance of commercially available trenchless spot-repair methods in the City's wastewater pipelines. This paper reports short-term testing procedures and results for two epoxy resin repair methods that were a part of the study. Both methods of repair were proposed by the City of Austin Department of Water and Wastewater, and were field demonstrated in Austin on 200-mm (8-in.) unreinforced concrete wastewater lines. Each process uses remote control, cured-in-place techniques: one method employs a robot to prepare substrate surfaces and to inject epoxy into pipe defects; the other employs an inflatable rubber packer to form a continuous epoxy collar up to 0.6 m in length at the defect. The objective of the study was to evaluate and compare, by field sampling and laboratory testing, the structural integrity and watertightness of the repair processes. A small number of repair samples were obtained by excavation of actual damaged pipe repaired by each method. Tests of the repaired pipe yielded results for bond strength and watertightness of the repair, which differ sharply between the two methods. Possible causes of bond failure are discussed.

A European high-speed train network is profitable from a collective point of view. But the schemes devised by the European Union seem to be much too ambitious, and should be carefully fine-tuned. The project encounters difficulties on the grounds of interoperability between countries and funding, as the financial rates of return of the projects are lower than their collective rates of return. Anyway, a major issue will be to foster competition to increase the creation of new services. A means to go in that direction would be to decrease the scale of franchised services, and to attribute paths through systematic auction bidding. A unique European regulator is desirable, but it is not clear whether new tracks should be built and managed by the incumbent infrastructure operators through some kind of private financing and bidding process.