钢桁架-圆钢管混凝土柱连接区段抗震性能试验研究与承载机理分析

Experimental research on seismic performance and analysis on load bearing mechanism of steel truss-to-circular CFT column subassemblage

高铁客站采用钢桁架-圆钢管混凝土柱结构,其连接构造复杂、用钢量大,且具有不同于传统梁柱节点的受力性能。对该类连接进行构造改进,取消钢管内部的加劲板,并对改进后的连接区段进行了往复加载试验。试验结果表明:改进后的大跨度钢桁架-圆钢管混凝土柱连接构造简单、合理有效;连接区段的柱与桁架之间的强弱关系对破坏模式与抗震性能有较大影响;高铁客运站柱轴压比较小,使连接区段的钢管混凝土柱适当弱于桁架可获得更好的变形与耗能能力。基于叠加原理,提出了连接区段的简化理论分析模型,预测的承载力及荷载-位移关系与试验吻合较好。

A kind of connection between steel truss and circular concrete-filled tube column has been adopted in some high-speed railway stations in China recently.This kind of connection which consumed a large volume of steel has complicated construction details and differs from traditional beam-to-column connection in mechanical performance.Some improvements on connection details were proposed.Cyclic tests were carried out on connection subassemblages.Test result shows that the improved large span steel truss-to-circular CFT column connection has both simple and effective construction details.It is also shown that relative strength relationship between the column zone and the steel truss has great effect on the seismic performance and the failure modes.Columns used in the high-speed railway stations have a small axial compression ratio.Better deformability and energy dissipation capacity can be obtained if the column zone is a little weaker than the steel truss.Based on superposition approach,a simplified theoretical model of the subassemblage was put forward.The load-displacement relationships and the strength predicted by this model agree well with test results.Test phenomenon can then be explained by this mechanics-based model.