Abstract
Two columns under a large number of repeated reversal laterl loads were analyzed by three-dimensional nonlinear Finite Element Method, wherein the columns were considered as being composed of core concrete, cover concrete, reinforcing steel and the bond between concrete and steel. The non-linear behavior of core concrete was represeted by assuming three-dimensional plasticity theory. The analyzed test sprecimen A is a column in which not only displacements and strains of longitudinal reinforcement but also strains of lateral reinforcement were measured in many locations. The specimen is suitable for the comparative study with the three-dimensional analysis. First the analysis for monotonically increasing loading is described, which is compared with the envelope of obtained experimental results. The obtained story deflections and the progressive process of yielding shows good coincidence with observed results. Next analysis for repeated reversal loading is described. Three cycles from the positive to negative region were analyzed, which were the initial cycles of repeated loops of a constant story deflection. Here story deflection and strains of longitudinal reinforcements are compared with observed results. Further strains of lateral reinforcements which are arranged not only parallel but also perpendicular to the lateral load are presented with observed ones. As the results their hysteretic behavior is well simulated. Further the specimen B was analyzed for two cycles. The obtained story deflection and strains of longitudinal reinforcements are compared with observed results.
