DAMAGE EVALUATION IN STEEL BOX COLUMNS BY CYCLIC LOADING TESTS

In Japan, bridge piers with hollow box sections are commonly used in highway bridges. These steel piers are characterized by a low axial force ratio, and therefore are designed with high width-thickness ratios of component plates. They are also particularly susceptible to damage during severe earthquakes. To assess the damage sustained, the authors develop a damage model based on cyclic loading tests on hollow box columns that represent bridge piers. The box columns are tested under a constant axial load and cyclic lateral loads. The degree and type of damage sustained depends on parameters of the structure and the loading history. The overall behavior is assessed by means of a damage model that considers these effects. The parametric constants of the damage model are evaluated using test results. Since residual strength is an important physical measure of the damage sustained, approximate expressions for correlating the residual strength and the damage index are suggested. The damage model presented is intended to be used to quantify the damage sustained under earthquake loading.