IMPROVEMENT IN SEISMIC PERFORMANCE OF EXISTING CYLINDRICAL STEEL PIERS BY TAKING ADVANTAGE OF CONTACT EFFECT OF NEWLY ADDED LONGITUDINAL STIFFENERS AS REINFORCEMENT

Abstract

  In order to seismically strengthen existing bridge piers, it is commonly required to improve only their ductility while suppressing any excessive strengthening of load bearing capacity. In the present study, we proposed and verified a new method, which is, unlike the conventional method of providing longitudinal stiffeners, the same stiffeners are provided to existing cylindrical steel piers while elaborately allowing a slight gap in between the bottom of a stiffener and bottom plate of a pier. The estimated seismic effect has been verified by an experiment and the numerical analysis. Our studies showed that only the ductility has been effectively increased by being contacted the bottom of stiffeners and the bottom plate of piers after seismic force has reached a maximum level.