【摘要】 以北京某办公楼实际工程为依托,对内芯为十字形的全钢防屈曲支撑进行支撑构件及子系统足尺试验研究,以了解其性能及合理构造。首先根据性能要求进行初步设计。继而在MTS上对设计的第一根构件进行单轴拉压试验,由于加工精度不足引起的偏心等原因,出现绕弱轴弯曲,试验终止。改进设计制作第二根构件进行试验,内芯在其与外套管点焊位置断裂,表明内芯屈服段除必要的板件之间的连接焊缝外,不应出现额外焊缝连接接头。采用在下端加劲肋处局部加厚方式限制外套管下滑,设计了第三根构件并安装到加载框架上进行子系统足尺试验,完成加载制度时支撑完好,且滞回曲线饱满稳定,受压强度提高系数及累积延性系数均满足规程要求。试验证明,改进后的十字形内芯全钢防屈曲支撑具有良好的延性及耗能能力。更多还原

【Abstract】 Full-scale uniaxial and subassemblage tests are conducted to study the property and proper configuration of all-steel BRB with cruciform cross section encased in a square steel tube, which is to be installed in a six-floor office building in Beijing. The first BRB specimen was designed according to the client’s requirement, and tested without gusset plates under uniaxial quasi-static cyclic loading by using MTS actuator. The top end bent during the loading process because of the initial eccentricity caused by machining error of the end part. The design is then improved and another BRB specimen is fabricated according to the test results of the first one. Under uniaxial cyclic loading, its core plates are fractured at the weld spots, indicating that there should be no additional weld on the yielding part of the core except the necessary connection between the core plates. For the specimen in the subassemblage test, which includes BRB and gusset plates, thickness of the portion of the rectangle reinforcing ribs outside of the outer tube are increased to restrain the slippage of the tube. No rupture is observed during the subassemblage test, and numerous hysteretic loops are obtained. The compression strength amplification factor and the cumulative inelastic ductility factor satisfy the standard of the SEAOC-AISC recommended provisions. The results show that the improved all-steel BRB with cruciform cross section encased in a square steel tube presents large ductility and high energy dissipation capacity.更多还原