外置钢管补强圆形钢桥墩的抗震性能

目的研究钢管径厚比和桥墩柱长细比参数对外置钢管补强圆形钢桥墩承栽力、延性和吸收能量的影响．方法在确定数值分析与实验数据吻合的基础上，采用MARC有限元程序，对外置钢管补强的圆形柱7个试件进行非线性数值分析．结果得到了在一定垂直荷载和水平往复荷载作用下荷载一位移滞回曲线．明确了外钢管的设置改善桥墩具有良好抗震性能的机理：当内钢管底部变形达到两管间的Dgap时，外钢管阻止了内钢管局部变形的发展，提高了结构的延性和承载力．结论除了λ＝0．15试件，其他的试件都是在56。时达到最大承载力，并且其大小变化不大．结构延性随着λ（或R1）的增大而减少．

Study on Seismic Performance of Steel Tubular Bridge Pier with Outer Pipe

In order to study the effects of the radius - to - thickness ratio Rt and the slenderness ratio A parameters on ultimate strength, ductility, energy absorption of steel tubular bridge piers with outer pipe, numerical analyses are carried out by finite element package MARC. In order to check the validity of the FEM analysis, these numerical results of tubular column with outer pipe are compared with the previous experimental results. Seven specimens are analyzed. Nonlinear horizontal force - displacement curves are obtained under constant axial load and cyclic horizontal load. The mechanism which improved seismic performance of steel bridge pier has been found：when local buckling displacement at bottom part of tubular column reaches the distance between tubular column and outer pipe （Dgap） , the outer pipe prevents deformation of tubular column developing and improves strength and ductility. It has also been found that when displacement at the top of columns reaches 56y, these specimens reach the maximum strength and the maximum strength changes very little except for the specimen of λ = 0.15. Ductility decreases rapidly with the increasing of λ （or R1 ）.