Finite Element Modeling and Bridge Reliability Evaluation

Abstract

In this study an investigation is conducted on the methodology used to analytically evaluate the safety of existing bridges. This methodology is presented and applied to one of the oldest types of bridges, truss bridges. An interpretation of the AASHTO loading for the bridge is presented. Four finite element models are identified and described: two two-dimensional models, one composed entirely of truss elements and one containing beam and truss elements; and two three-dimensional models, one composed of beam and truss elements only and one including beam, truss, and shell elements. Utilizing both deterministic and probabilistic techniques, the results obtained from the models are evaluated and compared, indicating that simplistic two-dimensional models which neglect the effects of longitudinally and transversely eccentric loading and possible internal horizontal stresses induced by stringer/deck interaction are not conservative.