Reliability-Based Performance Model for Large Bridge Component Systems

A method for modeling the performance of large bridge components subjected to normal loading and deterioration effects using reliability engineering techniques is presented. Development of the method was motivated by the need to advance a practical performance model for large bridge rehabilitation decision analysis. The modeling scope includes three basic elements: performance assessment, system modeling, and failure rate analysis. Two fundamental assumptions of the developed performance model are that (a) bridge components are systems of independent critical elements and (b) each element’s failure rate is constant throughout its functional service life. The model is used to qualitatively assess the performance of bridge components with respect to reliability and enables the estimation of two important rehabilitation planning indices, functional service life and expected damage. An application of the model is illustrated in an example involving a comparative evaluation of the performance of two large bridge deck systems. The bridges selected have similar traffic, maintenance, and environmental conditions; however, they have significantly different design characteristics. It is concluded that the performance model provides a viable approach to qualitative and quantitative evaluation of bridge performance over time. The research efforts described are part of a larger, comprehensive project to develop and enhance the bridge management system of the New York State Thruway Authority.