端板连接可更换Q235耗能梁段钢框筒子结构滞回性能及其影响因素研究

HYSTERETIC BEHAVIOR AND INFLUENCE FACTORS OF STEEL FRAMED-TUBE SUBSTRUCTURE WITH REPLACEABLE Q235 LINKS CONNECTED BY END PLATES

对2个2/3缩尺的单跨双半层含端板螺栓连接Q235耗能梁段钢框筒子结构试件进行了两阶段低周反复荷载试验,以研究其抗震性能、耗能梁段的可更换性和耗能梁段长度的影响。采用耗能梁段腹板试样的拉压往复试验结果标定了混合强化模型参数,利用子结构试件的试验结果验证了有限元模型的有效性,并研究了耗能梁段长度和腹板面积的影响。研究结果表明:耗能梁段的可更换最大层间位移角分别可达到0.43%、0.39%,耗能梁段的替换可以使结构的性能恢复到初始水平,耗能梁段的超强系数和破坏塑性转角分别大于Popov等建议的1.5和AISC341所给的限值0.08 rad;子结构有良好的延性,耗能梁段长的子结构的延性系数、累积耗能大于耗能梁段短的子结构的相应值;破坏模式为耗能梁段加劲肋倒角处的焊缝裂纹扩展延伸引起的腹板撕裂;建议耗能长度取柱中心距的0.10倍~0.24倍,长度比取0.55~1.32;耗能梁段腹板面积对子结构的承载力、累积耗能影响较大。

Two 2/3 scaled one-bay double-half-story steel framed-tube substructure specimens with replaceable Q235 links connected by end plates were subjected to two-stage low cyclic loading tests to study their seismic performance, replaceability of links and the influence of link length. The parameters of the nonlinear isotropic/kinematic hardening model were calibrated by conducting tension and compression reciprocating tests on the samples of link web. The results of the tests were used to verify the validity of the finite element models of the substructure specimens, and the influence of link length and link web area was analyzed. The results show that the replaceable maximum story drift angles of the links can reach 0.43% and 0.39%, respectively, and the replacement of the links can restore the performance of the structure to the original level;the overstrength factor of the links is greater than 1.5 which is recommended by Popov et al, and the failure plastic rotation angles is greater than the limit value of 0.08 rad given by AISC341;the substructures have good ductility, and the ductility coefficient and cumulative energy dissipation of the substructure with a long link are greater than those with ashort link;the failure modes are web tearing caused by the crack propagation of the weld at the chamfer of link stiffeners;the link length is recommended to take(0.10~0.24) times the centerline spacing of the columns, and the length ratio takes 0.55~1.32;the link web area has great influence on bearing capacity and accumulated energy consumption of the substructures.