Seismic evaluation of precast bridge columns with built-in elastomeric pads

A novel built-in elastomeric pad was incorporated into the plastic hinge zone of precast bridge columns with grouted corrugated duct connection to improve its seismic performance. Appropriate energy dissipation and minimal local concrete damage are expected in the innovative precast reinforced concrete (RC) columns. Four 1/4-scaled bridge column specimens were designed and tested under constant axial compression force and cyclic lateral loads to evaluate the feasibility and effectiveness of the proposed concept. Detailed experiment results were compared and discussed. The testing results showed that the main seismic index of precast RC bridge columns with grouted metal corrugated duct connection was similar to that of the cast-in-place bridge columns. It was also found that the precast RC column with a built-in elastomeric pad in the plastic hinge zone effectively minimized local concrete damage at the bottom of bridge columns and increased the energy dissipation capacity. The laminated elastomeric pad is recommended to be applied in the precast bridge column to maintain necessary initial stiffness and energy dissipation capacity and to avoid lateral bulge of single thick rubber. Excessive buckling and shear deformations of longitudinal rebars should be prevented by inserting a rectangular or square steel tube at the center of the elastomeric pad.