开孔形式影响装配式耗能支撑滞回性能研究

装配式H型钢腹板开孔耗能支撑是由腹板开孔H型钢和传力槽钢通过螺栓连接组成的新型耗能支撑，可有效避免支撑构件失稳。为了研究腹板开孔形状对这种支撑的耗能性能的影响，进行了装配式耗能支撑试件低周往复加载试验，并采用有限元软件进行了模拟计算。试验结果表明:装配式H型钢腹板开孔耗能支撑滞回曲线饱满，耗能能力强，变形能力好。在轴向荷载作用下，试件主要依靠开孔腹板孔间板件进入塑性变形耗能阶段，腹板开长圆孔的试件与腹板开椭圆孔的试件孔间板件端部为薄弱部位，腹板开菱形孔的试件孔间板件中间部位为薄弱部位，加载过程中这些部位首先进入塑性变形阶段并最先发生断裂。加载过程中螺栓与槽钢始终处于弹性变形状态。有限元分析表明:改变腹板宽度对于腹板开长圆孔的耗能支撑的承载能力与初始刚度影响最大，对于腹板开椭圆孔的耗能支撑影响最小；改变孔间板件宽度对于腹板开菱形孔的耗能支撑影响较小。改变腹板厚度对于三种腹板开孔形式耗能支撑的承载力与初始刚度影响相近。当试件主体过早失稳，可通过增大高宽比、减小腹板厚度或选用翼缘更大的槽钢来避免。耗能板件螺栓连接部位安全可靠，未见变形或破坏，布置螺栓时孔距不应超过4.5d₀。

INFLUENCES OF THE SHAPE OF HOLES ON THE HYSTERETIC PERFORMANCE OF ASSEMBLED ENERGY DISSIPATION BRACES

A novel type of brace composited of H-shaped steel with holes on the webs, force transmission channels and assembling bolts was proposed for structural energy-consumption and buckling restraint. The effects of the web holes on the energy dissipating ability of the brace were studied by cyclic axial loading tests and the finite element method. The test results indicate that this type of brace has a remarkable hysteretic behavior. The energy dissipation and failure mode of brace specimens were governed by the plasticity development of the plates between the web holes, in which the plastic zones were concentrated at the ends of the plates between slotted or elliptical holes and in the middle of the plates between diamond holes. All bolts and channels remained elastic throughout the tests. The finite element analysis reveals that the width of the web greatly affects the initial stiffness and strength of the braces with slotted holes, while it only slightly affects the behavior of the braces with elliptical holes. The hole distances had a minor effect on the behavior of the braces with diamond holes. The effects of the web thickness on the initial stiffness and strength of the braces with slotted, elliptical, and diamond holes were similar. Design suggestions were proposed according to the analysis results that the premature buckling can be avoided by increasing the height-to-width ratio, by reducing the web thickness of H-shaped braces, or by enlarging the flanges of the channel, and that the bolt spacing shall be less than 4.5 times the diameter of the bolt holes.