Development of Seismic Control Devices unifying some bridge systems

本文研究了双向循环位移荷载对空心圆柱延性的影响，提出了管形截面桥墩在两个水平地震分量耦合作用下的抗震验算方法。为此，以径厚比和长细比为主要设计参数，对有限元模型进行了非线性数值分析。分别推导了单向和双向循环荷载下基于应变的延性公式，并在此基础上提出了一种抗震验算方法。为了验证该方法的有效性，对三种不同的桥墩梁单元模型进行了非线性动力分析。采用基于位移和基于应变的方法对结构的变形和应变性能进行了评价。对比研究表明，基于应变的地震验证法比基于位移的验证法更为关键。此外，与以往极限应变公式的许用值进行了比较，表明本文推导的公式更适合于圆形钢桥墩在双向地震作用下的抗震验算。最后，讨论了在桥梁系统中安装抗震控制装置的一些问题。结果发现，地震控制装置的优化布置方法还没有发展起来。因此，在重新考虑一些结构参数的情况下，将制定新的将地震控制装置放置到桥梁系统中的程序。

This work deals with influence of bi-directional cyclic displacement loading on the ductility of hollow circular steel columns and to develop a seismic verification method for bridge piers, with pipe sections, when subjected to coupling action of two horizontal earthquake components. For this purpose, nonlinear numerical analyses are performed on Finite Element models by setting radius-thickness ratio and slenderness ratio as main design parameters. The strain-based ductility formulas are developed separately for uniand bi-directional cyclic loadings, and based on these formulas a seismic verification method is proposed. To confirm this method, nonlinear dynamic analyses are carried out on three different beam element models of bridge piers. The deformation and strain performances are evaluated by displacement-based and strain-based methods. The comparative study shows that the strain-based seismic verification method is critical than displacement-based method. Further, comparison between allowable values given by past ultimate strain formula indicates that the formulas developed in the present study are more adequate to use in seismic verification of circular steel bridge piers when subjected to two directional earthquake motions at the same time.Finally, some various problems installing seismic control device into bridge systems are discussed. As a result, it was found that the method placing seismic control devices optimally is not developed yet. Therefore, newer procedure locating seismic control devices into bridge systems will be developed with reconsidering some structural parameters.