SEISMIC REINFORCEMENT OF EXISTING CYLINDRICAL STEEL PIERS BY TAKING ADVANTAGE OF CONTACT EFFECT OF ADDED STIFFENERS

为了对既有桥墩进行抗震加固，通常只要求提高桥墩的延性，同时抑制任何过度加强的承载能力。在本研究中，我们提出并验证了一种新方法，即与传统的提供纵向加劲筋的方法不同，在现有的圆柱形钢墩上提供相同的加劲筋，同时精心允许加劲筋底部与墩底板之间有轻微的间隙。通过试验和数值分析验证了估计的地震效应。我们的研究表明，在地震力达到最大水平后，只有加强筋底部与桥墩底板接触才能有效地提高延性。

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.