SEISMIC PERFORMANCE AND EFFECTS OF DIFFERENT JOINT SHAPES FOR UNBONDED PRECAST SEGMENTAL BRIDGE COLUMNS

To study the seismic performance and the effects of different joint shapes for unbonded precast segmental bridge columns under low-reversed cyclic loading, two 3-D finite element (FE) models respectively using plane-contact joints and shear resistant joints were established. In the FE models, the mechanical behaviors of concrete and tendons were respectively described by the damage-plastic model and the bilinear model, and the contact criteria was based on Coulomb's Friction. The results of nonlinear time history analysis showed that the deformation of the columns was mainly composed of alternately open-closed joints, and the failure of the column was mainly caused by concrete crush on the bottom segment. Compared with two model's hysteresis loop, backbone curve, ductility and residual deformation, it was found that the column with shear resistant joints had longer stable period of strength, better ductility, and smaller residual displacement than the column with plane-contact joints, so it had better seismic performance.