Abstract
Occurrence of local buckling affects the load carrying capacity of steel bridge piers. Recently, long duration time motions were observed during huge subduction-zone earthquakes, and steel bridge piers buckled locally behaved under dozens of cycling motions. However, influence of high repetition shaking with yield load level on seismic behavior of steel bridge piers is left the unsolved problems. Central Disaster Prevention Council predicts the occurrence of huge subduction-zone earthquakes, in the near future. Therefore, this study evaluates the load carrying capacities of steel bridge piers during dozens of elastic range cyclic loading after maximum yield displacement of earthquake motions. In the numerical calculation, three FE models were prepared to confirm the effect of difference of width-thickness ratio (= Rf) as the buckling parameter. The results of numerical calculations show that the smaller Rf steel bridge pier has, the smaller reduction ratio of load carrying capacity during cyclic loading. Then, each Rf analytical model show the deferent S-S curve as the detailed mechanism of load carrying capacity decreasing.
