Non linear seismic response analysis of the Aratsu cable-stayed bridge

In this paper, the seismic capability of existing steel cable-stayed bridges was checked by nonlinear seismic response analysis using the observed records that were obtained at the 1995 Hyogoken Nanbu Earthquake. The effect of boundary condition (consideration of soil spring), modeling of bearing supports on the pier, existence of tuned mass damper at the top of the tower are investigated. As a result, it is evident that the main steel tower, the main steel girder and the main part of the reinforced concrete pier are safe but there is some defect at the bearing supports. In the case of longitudinal excitation, relative displacement between upper and lower part of a movable bearing becomes ten times of displacement allowance. On the other hand for transverse excitation, reaction forces for the bearings of the girder are larger than design force, and axial forces of set bolts ate larger than the tensile strength of them.