RESPONSE ANALYSIS OF ROCKING BRIDGE PIER FOR SEISMIC RESILIENCE

Abstract

The transportation system is highly susceptible to major earthquakes and is primarily built to withstand collapse. The use of conventional concrete bridge piers will undergo significant damage during the seismic action making it not accessible for transportation facilities. Rocking bridge piers is an alternative to conventional concrete bridge piers. The rocking piers have enhanced seismic resilience. Rocking causes the rotational movement of piers about the point of contact at edge. The rocking motion helps in the self-centering action of the bridge pier. They will not form plastic hinges and thus reducing the residual displacements. But the use of purely post-tensioned rocking bridge piers will not be practically feasible under the action of wind loads. Hence, in this study the rocking bridge pier is designed in such a way that the longitudinal bars will take up the gravity load and additional moment due to earthquake will be taken by the post-tensioning tendons. The reinforcements are like a snap through reinforcement. The seismic response analysis of the fixed base and rocking base piers are done in OpenSeesPy. It was observed that the rocking base pier experience negligible residual drift as compared to fixed base pier. But the energy dissipation of rocking bridge piers is very less due to lack of plastic hinge formation and inelastic displacements. So, response analysis was conducted for the rocking bridge pier with additional energy dissipators called BRBs to check whether the amount of energy dissipated is increasing or not. The response analysis with BRB showed that the rocking pier with BRBs helped in increasing the energy dissipation.