郑宏+孟春辉+石丹

摘要：为研究翼缘削弱型节点空间钢框架在低周反复荷载作用下的抗震性能，采用有限元分析软件ABAQUS对普通节点和翼缘削弱型节点的空间钢框架模型进行有限元模拟，对2种钢框架模型的破坏形式、承载力、滞回性能、耗能能力、强度及刚度退化性能等进行了对比分析。结果表明：翼缘削弱型节点可使梁端塑性铰外移至梁端翼缘削弱处，避免梁端焊缝处应力集中导致脆性破坏；翼缘削弱型节点等效粘滞阻尼系数与普通节点空间钢框架相比有明显的提高，进入屈服阶段后由于应力重分布，其刚度及承载力退化速度较普通节点空间钢框架慢，翼缘削弱型节点钢框架具有梁铰延性破坏机制，抗震性能较好。

关键词：翼缘削弱型节点；空间钢框架；有限元分析；塑性铰；滞回性能；抗震性能

中图分类号：TU323.5文献标志码：A

Abstract： In order to study seismic performance of reduced beam section connection steel frames under lowcyclic loading， finite element simulation analysis of space steel frames with common connections or reduced beam section connections were carried out using ABAQUS software. Based on the finite element simulation analysis results， the failure mode， bearing capacity， hysteretic behavior， energy dissipation capacity， strength and stiffness degradation of the two types of steel frames were compared. The results show that the reduced beam section connection can let the plastic hinge of beam end move outward to beam end flange weakened， and avoid welded connection brittle fracture induced by stress concentration. The equivalent viscous damping ratio of reduced beam section connection steel frame is obviously greater than common connection steel frame. When the steel frames enter the yield stage， the stiffness and bearing capacity degradation of reduced beam section connection steel frame is slower than common connection steel frame. The reduced beam section connection steel frame has beam hinge ductility failure mechanism， and the seismic performance is better.

Key words： reduced beam section connection； space steel frame； finite element analysis； plastic hinge； hysteretic behavior； seismic performance

0引言

钢结构具有造型美观、施工速度快、抗震性能突出、节能可再生等优势，已经成为大型公共建筑、高层和超高层建筑、工业建筑的主要结构形式。在1994年美国北岭地震和1995年日本阪神大地震中，被认为具有优良延性的钢框架结构发生了严重的脆断破坏，钢材的良好延性并没有表现出来，地震调查数据表明破坏主要是梁根部翼缘坡口焊缝出现应力集中以及梁柱连接焊缝质量缺陷造成的[14]，震后钢框架梁柱节点问题成为研究热点[5]。为了保证塑性耗能发展之前梁柱连接焊缝处不发生破坏，应避免钢框架塑性铰出现在受力复杂及应力集中的连接焊缝处，提高其抗震性能。……