局部加厚铸钢支座节点极限承载力数值分析

Numerical Analysis of the Ultimate Bearing Capacity of Cast Steel Support Joints With Localized Strengthened Components

结合空间管结构人行天桥在罕遇地震荷载作用下的弹塑性时程分析,采用ANSYS有限元分析软件,对底部局部加厚铸钢支座节点进行极限状态承载力数值分析。结果表明:底部局部加厚铸钢支座节点构造合理,极限承载力为设计荷载的3.45倍,具有较大的强度富余;铸钢支座节点在极限荷载作用下会产生很大的塑性应变,随着塑性应力重分布,节点弹性阶段与塑性阶段应力极值区域不在同一位置;指出铸钢支座节点在设计中必须进行极限状态分析才能确定其薄弱区域;同时,对铸钢支座节点进行底部局部加厚处理可以有效地提高节点极限承载力,相较于未局部加厚铸钢支座节点极限承载力提高了15%。分析所得结果数据可以为铸钢支座节点的破坏形式以及节点的设计提供一定的依据。

Elastic-plastic time history analysis of the cast steel joint in a footbridge major earthquakes were performed by using the FEM software,ANSYS.This joint was partially strengthened.Analysis results indicate that the ultimate bearing capacity can reach 3.45 times of the design load.Cast steel joints have significant plastic strain under the ultimate load.With stress redistribution,the location of the maximum stress changes as steel goes into the plastic range.Therefore,the limit state analysis should be implemented for cast steel joints to determine the weak component in structural design.It is also indicated that the cast steel joint with locally strengthened bottom components can improve the ultimate bearing capacity of the joint effectively with about 15% strength increase.