ANALYSIS OF TIME-DEPENDENT CHARACTERISTICS FOR CABLE STATE OF EXISTING CABLE-STAYED BRIDGE

In view of the fact that steel cables of cable-stayed bridge are susceptible to corrosion and tend to become stress relaxation during service life, it is essential to take those time-dependent characteristics into account in structural analysis to ensure the safety of the existing bridges. However, most of the recent methods are given under the cable material in perfect state and cable effects of time-dependent characteristics associated with cable corrosion and stress relaxation are neglected, which makes the application of the current methods difficult in dealing with in-service cable structures. By introducing equivalent-strain principle and geometrical damage theory, the corrosion mechanism of cable is described. A UL formulation for cable state of existing cable-stayed bridge is presented by solving the boundary problem with the governing differential equation of the in-service cable. With the proposed method, cable corrosion as well as stress relaxation has been taken into consideration, which leads to good precision and provides a new approach to assess the safety of cables in cable-stayed bridges, and it could be applied in structural health monitoring of long-span cable-stayed bridges.