Journal of Infrastructure Systems

The overall aim of this paper is to work out the guidelines for efficient maintenance planning connected with the basic public utilities. The empirical section acts as a platform for the next section where the economic model is related to the empirical results. It is crucial to emphasize that planning should be carried out in two stages: (1) The fundamental planning problem; and (2) the complementary control problem. First the fundamental planning problem results in a plan where each separate object has a number of combinations of maintenance measures together with a point in time for each measure. In the next stage the resources needed and the budget requirements for each of these combinations is discussed.

A structural reliability analysis model is developed to include interaction between transverse cracking, diffusion of chlorides, and corrosion initiation; influence of design specifications on corrosion initiation and propagation; and serviceability limit states (e.g., spalling). The reliability model is used to evaluate probabilities of structural and serviceability failures for flexure and spalling limit states, for a typical reinforced concrete bridge continuous slab. Chloride contamination will occur from the application of deicing salts. It was confirmed that the application of deicing salts caused a significant reduction in structural and serviceability reliabilities; this observation is in agreement with field data of bridge performance. Moreover, the reliability analysis allowed the effect of corrosion to be measured in a quantitative manner. The influence of concrete cover and specified concrete compressive strength was found to be particularly significant on the probability of spalling. The reliability analysis is used to demonstrate how known exceedence of a serviceability limit state (spalling) can be used to update the probability of structural failure. The time-dependent reliability analysis developed in the present paper may, at a later stage, be applied to other reinforced concrete bridge structural configurations or be used as the reliability module in existing inspection, maintenance, or load rating procedures, i.e., bridge management systems.

This paper presents a proactive method to identify and evaluate ramp characteristics that present a rollover hazard for trucks. It uses ratings developed from a survey in which experts in highway design and operations rated the relative extent to which deficiencies in each of the characteristics of a ramp might contribute to a truck rollover. Fuzzy math is used in the synthesis of the experts' opinions to numerical values that can be used by highway safety practitioners. The ratings are used to develop Notice Ratings, which are numerical evaluations of the relative rollover hazard that exists on a ramp. The Notice Ratings can be used to set priorities for corrective action. An example of their use in cost-effectiveness analysis is given in this paper.

The paper reviews needs and opportunities to reduce the vulnerability of public water systems to willful attack. Water supply infrastructure systems, and their components are described in general. The terrorist threat is described, classifying potential physical, chemical-biological, and cyber attacks to these systems. A hierarchical holographic model is introduced for multiple perspectives on the hardening of water systems. Types of hardening are defined, including security, robustness, resilience, and redundancy. The paper concludes with recommendations and opportunities for future research into quantitative risk analysis, an adaptable template for threat assessment and hardening, pacts providing for mutual emergency aid, potential psychological impacts, economic consequences distinguished from threats to life, education and training needs, and case studies of typical systems. Overall, the paper provides a foundation for improving the assessment of the risk of willful attacks in the management of civil infrastructure systems.

A methodology for system-wide estimation of environmental mitigation costs based on a stratified random sampling technique is presented, and its application is illustrated using the highway noise barrier needs of a large metropolitan area. The system-wide highway noise barrier infrastructures cost figures are usually based on rough estimates. A methodology is needed to systematically estimate the cost of the entire system using the cost data from a representative sample of sites. Random sampling and stratified random sampling were not appropriate. A balanced stratified random sampling methodology for selecting a small number of representative sites when the sample size is smaller than the number of combinations of strata was developed. A representative sample of sites was selected, and the cost data from the sites were used to estimate the construction cost for the entire noise barrier system. This paper discusses criteria for selection of the representative sites, development of a procedure for selecting the sites, and three approaches for estimating the noise barrier construction cost for the entire study area using the balanced stratified random sampling technique. The methodology is generic for system-wide estimation of environmental mitigation costs, and noise mitigation is simply used as a sample application.

This paper details the work of the recent Bridge Seismic Retrofit Program for the city of Los Angeles. We describe the scope of the work completed and project funding through local and federal sources. The criteria used for the categorization of a bridge as a historical structure is explained, and the subsequent funding and design impacts are detailed. Methods of prioritizing the bridge retrofits using a weighted formula based on replacement cost, condition of the bridge, bridge traffic, and age of the structure are introduced. The engineering solutions to the typical bridge seismic deficiencies of loss of support at the rocker bearings and expansion hinges, column failures, failures of pier walls, foundation failures, and abutment failures are all reviewed. We summarize the bridge construction program history and progress. The work done to one bridge, the Cesar Chavez Bridge, is detailed to illustrate a representative project within the program. Our conclusions identify the successes and shortcomings of this major infrastructure improvement program.