钢-混凝土组合框架子结构动态倒塌性能试验研究

为了研究中柱失效后钢-混凝土组合框架结构的动态倒塌性能,对2个1/3缩尺的组合框架子结构试件进行了抽柱试验研究。研究结果表明:当在组合框架梁上分别悬挂30 kN和60 kN的配重时,2个试件在中柱处的最大动态位移至少为振动停止后静态位移的1.34倍;在中柱抽除后,剩余结构仍处于弹性受力阶段且阻尼比较小;采用栓钉抗剪连接件的组合框架梁具有较大的加速度响应和动态位移响应;组合梁中采用开孔板连接件的框架子结构具有较好的整体刚度,其受倒塌荷载动力冲击作用的影响相对较小;随着中柱竖向位移的增加,组合框架倒塌荷载动力增大系数(DIF)呈现两阶段的变化规律。基于试验研究,建立了组合框架倒塌荷载DIF的数学计算模型。该研究成果可为钢-混凝土组合框架结构的倒塌性能分析提供参考。

Tests for dynamic collapse performance of steel-concrete composite frame substructures

To investigate the dynamic collapse performance of steel-concrete composite frame structures after a middle column was removed, two one-third reduced scaled composite frame substructures were tested by removing a column. Experimental results showed that when additional weight of 30 kN and 60 kN were hung on the composite frame beams respectively, the maximum dynamic displacement at the middle columns of the two specimens was at least 1.34 times of the static displacement after the vibration stopped. The residual structures were still working in the elastic stage after the removal of the middle column and the damp ratios were both minor. The composite frame beams using studs shear connectors presented larger acceleration response and dynamic displacement response. While the frame substructure with perforated plate shear connectors used in the composite beams had better integral rigidity and was less affected by the impact of the dynamic load comparing with the former. The collapse load dynamic increase factors (DIF) of the composite frames appeared two-stage changing rules with the increase of vertical displacement at the middle column. And then, the calculation model of collapse load DIF applying to composite frames was presented based on the experimental investigation. The research results of this paper could provide references for collapse analysis of steel-concrete composite frame structures.