装配式偏心支撑钢框架可替换性研究

Research on the Replaceability of Prefabricated Eccentrically Braced Steel Frame

为研究装配式偏心支撑钢框架在地震作用下的抗震性能与破坏机理,对两种1层单跨的剪切屈服型装配式偏心支撑钢框架进行了拟静力试验,分别从两种框架的斜撑构造以及可替换能力两方面研究装配式偏心支撑的抗震性能,观察钢框架在低周往复荷载作用下的破坏特征,结合试验结果深入分析此类结构的抗震性能指标。试验结果表明:斜撑构造对装配式偏心支撑钢框架的抗震性能有较大影响,斜撑与框架横梁间采用螺栓连接的钢框架REBF在承载能力、耗能能力、耗能梁段的转动能力等方面均优于上半部分斜撑与框架横梁间采用焊接连接的钢框架KEBF;但在可替换能力方面,KEBF框架替换耗能梁段后各项抗震指标与原框架相当,而REBF框架在替换耗能梁段后,其滞回性能、延性系数、耗能能力等较原框架均有明显下降,表明KEBF框架的替换性能更好。

To examine the seismic performance and failure mechanism of a prefabricated eccentrically braced steel frame under pseudo-static loads,two one-story,one-span prefabricated eccentrically braced steel frames are built.The seismic performance of prefabricated eccentric braces is examined from the angles of the diagonal bracing construction and the replaceability of the two frames.On the basis of the test findings,the failure mechanism of the steel frame under lowcycle reversed loading is observed,and the seismic performance indices of this kind of structure are thoroughly evaluated.The test findings indicate that the diagonal brace construction has a stronger effect on the seismic performance than the prefabricated steel frame with eccentric braces.The steel frame REBF,which is fastened between the diagonal brace and the frame beam,has the bearing capacity,energy dissipation capacity,and rotation capacity of the energy dissipation beam section.It is superior to the KEBF steel frame in which the diagonal brace and frame beam are welded together.However,the KEBF frame substitutes the energy-dissipating beam section and has equal seismic indices to the original frame in terms of its capacity to be replaced.Compared to the original frame,the hysteretic performance,ductility coefficient,and energy dissipation capacity of the REBF are dramatically diminished after the energy beam section.The KEBF frame is more replaceable.