Structural Reliability of a Suspension Bridge Affected by Environmentally Assisted Cracking

This paper deals with the environmentally assisted cracking behavior of high strength cable wires of a suspension bridge, expos ed to marine environments. The main objective is to determine the safety of a bridge system locally and globally. To evaluate the safety of a suspension bridge, an ultimate limit state for the local cracking in cable wires and service limit states for global respo nses of the bridge system are considered. In an ultimate limit state, the reliability of time-dependent and crack length-dependent Environmentally Assisted Cracking (EAC) of a cable wire has been calculated. Global system responses have been evaluated by a FEM program, which were used for the safety evaluation of service limit states. Due to the diffusion of hydrogen atoms affected by the gradient of hydrostatic stress, the section of cable wire will fail immediately when the ratio of EAC in a cable wire is la rger than 60percent. However, the global responses show ignorable differences in the considered analysis. Suggestions for the found problems are discussed.