多层高强钢组合K形偏心支撑钢框架抗震性能研究

Seismic behavior of multi-storey high strength steel composite K-eccentrically braced steel frame

高强钢组合偏心支撑是指耗能连梁采用普通钢材(Q345),而框架梁、柱等非耗能构件采用高强度钢材(Q460)的偏心支撑结构,这种结构体系不仅有效降低了构件截面,而且有助于高强度钢材的应用推广。为了研究其抗震性能,对1∶2缩尺比例的三层高强钢组合K形偏心支撑钢框架整体试件进行了低周往复加载试验,耗能连梁均为剪切屈服型。试验结果表明:高强钢组合K形偏心支撑结构具有较高的承载能力、良好的位移延性和耗能能力,二层耗能连梁的腹板受剪撕裂是试件破坏的标志,导致整体结构的承载力下降。试件最终破坏时,非耗能构件基本处于弹性受力状态,耗能连梁的弹塑性变形消散了大部分地震能量。另外,高强钢组合K形偏心支撑结构的延性指标受耗能连梁长度(e)与框架梁长度(L)比值影响,也与耗能连梁的转动能力有关,e/L越大,耗能连梁越接近于弯曲破坏,延性性能越好。

Composite eccentrically braced frames use Q345 steel links and high strength steel （Q460） members , thus the cross section of structural members can be reduced. A 1 ： 2 scale three-story K-type HSS-EBF （K-HSS-EBF） with shear links was tested under cyclic loads to study its seismic performance. The results indicate that the K-HSS-EBFs structure has good load-carrying capacity, ductility capacity and energy dissipation capacity. And the web tear of the link in second story can decrease the load-carrying capacity. The non-designated yield members remained in elastic stage while the link entered into the plastic stage completely to dissipate the energy in K-HSS-EBFs. The ductility capacity of K-HSS-EBFs is influenced by the plastic performance of the link, the ratio of link length （e） and the beam length （L）. With the increase of e/L value, the failure mode of link is similar to that of flexural links and the ductility capacity of the structure becomes better.