Lifetime reliability profiles for evaluation of corroded steelgirder bridges

摘要

Reliability methods can be used as an important and efficient tool in assessmentrnof new and existing structures. The traditional approach is based on consideration of individualrncomponents rather than whole structural systems. Therefore, it can be conservative and mayrnunderestimate the real response of structures. This paper is focused on the system behavior. Therndeterioration of existing steel bridges is a function of time due to natural aging, increasing loadrnspectra, corrosion, and other problems. Therefore, the paper presents the time-dependentrnreliability analysis for selected structures. Bridge structures exposed to aggressivernenvironmental conditions, are subjected to time-variant changes of resistance. There is a needrnfor evaluation procedures for an accurate prediction of the load carrying capacity and reliabilityrnof bridge structures, in order to make rational decisions about repair, rehabilitation, replacement,rnand expected life-cycle costs. The objective of this paper is to develop time-variant reliabilityrnprofiles for steel girder bridges. The proposed approach is based on the reliability analysis ofrncomponents and structural systems. The major steps of the procedure include selection ofrnrepresentative structures, formulation of limit state functions, development of load models,rndevelopment of resistance models for corroded steel girders, development of the reliabilityrnanalysis procedure, reliability analysis of selected bridges, and development of the timedependantrnreliability profiles. The resulting system reliability can be applied for a betterrnprediction of the service life of deteriorating steel girder bridges, and development of optimal