两种密肋框格屈曲约束低屈服点钢板剪力墙抗震性能试验研究

Experimental investigation on seismic behavior of two types of buckling-restrained low yield point steel plate shear walls with multi-stiffeners

通过对2榀缩尺比例为1∶3的两种密肋框格屈曲约束构造的低屈服点钢板剪力墙试件进行抗震性能试验研究,对比分析了两榀试件在低周往复荷载作用下的破坏形态、滞回性能、延性、刚度、承载力和耗能性能等,考察了框-墙之间的剪力分配关系,以此为基础检验了周边框架柱刚度阈值公式的有效性,探讨了钢板剪力墙结构的变形模式。研究结果表明:两侧密肋框格屈曲约束构造能够有效地抑制内填钢板的整体屈曲,使其实现"先屈服,再屈曲"的设计目标。两个试件的破坏进程符合"强框架,弱墙板"和"强柱弱梁"的设计理念,最终均呈平面内弯-剪破坏模式。结构的滞回环饱满呈梭形,具有稳定的承载与塑性变形能力,延性好,初始侧向刚度大。外框架与内填钢板之间的剪力分配转换平稳有序,能够组成合理可靠的双重抗侧力体系。给出了框架柱脚最大剪力和抗剪强度的近似计算公式,可以用于竖向边缘构件平面内受剪屈服的校核。提出了一般钢板剪力墙结构受剪承载力和受弯承载力的计算公式,便于工程设计人员进行内填钢板和周边框架规格的初步选择。

Quasi-static tests were carried out on two 1：3 scaled specimens of low yield point steel plate shear walls, whose infill plate utilized two types of buckling-restrained details with multi-stiffeners respectively. The comparative analyses on failure modes, hysteretic behavior, ductility, lateral stiffness, load bearing capacity and energy dissipation capacity between both types were conducted after the experiment. Then shear distribution between infill panel and perimeter frame was investigated. Next validity of stiffness threshold in frame columns and different deformation modes of steel plate shear walls （SPSWs） were discussed on the basis of above analyses. Research results show that the buckling-restrained detail with two side multi-stiffeners can effectively avoid overall elastic buckling of steel plate, reaching its design target of ＇ yielding before buckling＇. Failure mechanism on both of the specimens are reasonable, in according with design concepts of ＇ strong outside frame-weak infill panel＇ and ＇ strong column-weak beam＇ , and associating in-plane flexure-shear failure modes eventually. Hysteretic loops of the new structure are spindle, which also exhibits stable bearing capacity and plastic deformation ability, as well as substantial ductility and large initial lateral stiffness. The transfer of shear distribution between outside frame and infill plate is stead and orderly, indicating them can compose reliable dual system. Approximated formulas for calculating maximum design shear demand and shear strength at column base are presented to examine whether the column occurring shear yielding premature. Finally, design formulas on shear strength V~ and bending strength Vm for SPSWs are proposed, in order to provide reference for structural engineers on preliminary selection of infill panel and perimeter frame.