带肋薄壁箱形梁抗震性能研究

Study of the Seismic Performance of the Thin-Walled Box Beam with Stiffeners

本文对我国和美欧结构设计规范中箱形梁宽厚比限值规定进行了较为全面的回顾.针对大跨度箱形构件用钢量较大的问题,提出一种带加劲肋的薄壁箱形梁.采用ABAQUS非线性有限元分析软件建立了计算模型,对屈曲模态、承载力、变形性能、耗能能力和损伤情况进行了全面研究.计算结果表明:薄壁箱形梁设置加劲肋后,腹板的面外变形受到有效抑制,屈曲范围与波形数量均显著减少.在往复荷载作用下,带肋薄壁箱形梁承载力达到最大值后下降速度较为缓慢,滞回曲线梭形的宽度较大.随着腹板宽厚比增大,带肋薄壁箱形梁的最大变形能力与延性系数降低不大,刚度退化速度较慢,耗能能力较强.当达到相同变形角(1/75)时,腹板的最大面外变形与塑性应变均小于普通薄壁箱形梁,说明其损伤程度较轻.与腹板受宽厚比限值控制的普通薄壁箱形梁相比,带肋薄壁箱形梁可以在具有相同变形能力的同时,有效节约钢材.

A comprehensive review of the width-thickness ratio limitations of box-section beams in the structural design codes of China,the United States,and Europe is presented in this paper.A new type of thin-walled box beam with stiffener(TWBBS)was proposed to solve the problems of large steel consumption in large-span box-section members.An analytical model was established by ABAQUS nonlinear finite element software,and the buckling mode,bearing capacity,rotation performance,energy dissipation,and damage situation were studied comprehensively.The results showed that the out-of-plane deformation of the web was effectively restrained and the buckling area and number of waves were significantly reduced when stiffeners were installed in the thin-walled box beam(TWBB).Under the action of reverse load,the bearing capacity of the TWBBS degraded slowly after its maximum value,and the hysteretic curve showed a wide shuttle shape.As the width-thickness ratio of the web increased,the maximum deformation capacity and ductility coefficient of the TWBBS decreased little;the stiffness degradation rate was slower,and the energy dissipation capacity was better.At 1/75 rotation angle,the maximum out-of-plane deformation and plastic strain of the web were smaller than those of the ordinary TWBB,indicating that the damage degree was lower.Compared with ordinary TWBB whose webs are controlled by the width-thickness ratio limitations,the TWBBS can effectively save steel while having the same deformation capacity.