Journal of Infrastructure Systems

Integrated analytical and experimental research, conducted for exploring objective, global condition assessment and evaluation of bridge serviceability and safety, is summarized. A related terminology with definitions for critical terms is offered. Nondestructive and destructive field testing and structural identification of seven actual bridge test specimens enabled formulating a bridge condition assessment and reliability evaluation methodology. Field-calibrated analytical models, developed by structural identification, are studied to understand the real behavior and performance of actual bridges and to quantify relative contributions of different stiffness and resistance mechanisms. While our heuristic knowledge base has served us well, further rationalizing our bridge engineering practice is needed to achieve the optimum management of the highway transportation infrastructure necessary for continued advances in the next century.

Life-cycle cost is an important factor that should be estimated in the design and optimal management of infrastructure expected to be functional for a long period of time. In addition to initial construction cost, the estimation should include expenditures for maintenance, retrofit, and upgrading. This represents a relatively new concept whose application in the United States has been encouraged by passage of the 1991 Intermodal Surface Transportation Efficiency Act (ISTEA) for bridges. One problem associated with life-cycle cost estimation, as currently implemented, is that the costs associated with natural hazards, particularly future earthquakes, are not taken into consideration. The present paper provides a framework in which not only the initial capital and discounted maintenance cost but also the discounted cost for seismic retrofit and damage/repair cost from seismic events can be combined for a more realistic life-cycle cost estimation for bridges that are located in earthquake-prone areas. The framework provides economic insight into the various components of cost and identifies the specific information required for life-cycle cost estimation.

Local governments are increasingly responsible for the provision of roads. Arguments for decentralization assume that local agencies have a better understanding of local demands and are better able to allocate scarce resources and deliver services at lower costs. Counterarguments suggest that losses in economies of scale due to decentralization outweigh potential gains. We develop a model to measure the effects of decentralization of road provision. Using a 35-country panel data set we measure the impact of decentralizing expenditures for construction, maintenance, and administration. We find that decentralization results in lower unit costs of maintenance while unit costs of administration which initially decline with increasing degrees of decentralization, may increase when approaching total decentralization. Construction costs seem to be unaffected by the level of decentralization. Road user costs are only affected by decentralized maintenance. These results suggest that the gains to be made from decentralization depend on the type of activity being decentralized.

Corrosive exposure and subsequent deterioration of weathering steel structures cause strength loss due to cross-section thinning as well as crack susceptibility due to formation of notches that concentrate stresses. Key issues include rapidly drying versus extended wet time surfaces, the relationship of clean versus debris-covered surfaces to corrosion, and disparities between test site and service conditions. An adequate understanding of corrosion, corrosion's relationship to steel structure serviceability, and the ability to monitor, predict, and abate corrosion are important needs for weathering steel structures. To implement these needs, data on corrosive conditions were collected from corrosion coulometers placed on seven structures in varied environments, at one preconstruction site and at two corrosion test sites. An analysis of corrosion processes leading to cross-section thinning, notching, and loss of fatigue strength is presented. Improved service and maintenance, enhanced design methodologies, and cost savings are anticipated outcomes.

An international consensus on seismic design criteria for onshore pipelines has been established during the last 30 years. The need to assess seismic design for offshore pipelines has not been similarly recognized. The geotechnical hazard for a pipeline routed across steep slopes and irregular terrains affected by earthquakes are discussed in this paper. The integrity of both natural and artificial load-bearing supports are assessed. The response of the pipeline to direct excitation from soil or through discontinuous, sparsely distributed natural or artificial supports are commented on. Some applications are given in order to point out topical aspects and major design issues for currently operating offshore pipelines crossing seismic active seabeds.