配置可更换弧形角撑的钢框架结构振动台试验研究

Shaking table test of a steel frame with replaceable curved knee braces

为实现钢框架结构的震后快速修复,提出了一种配置可更换弧形角撑和高强钢构件的抗弯钢框架结构。在目标水准地震作用下,结构塑性变形集中在弧形角撑上,高强钢构件基本保持弹性以降低震后残余变形,震后可通过更换弧形角撑快速修复结构。为研究所提出结构体系的抗震性能以及更换弧形角撑的可操作性,设计了1个带混凝土楼板的1/2缩尺模型进行振动台试验。试验结果表明:该模型实现了预定的损伤控制机制,能够满足GB 50011—2010《建筑抗震设计规范》的最大层间位移角限值要求;由于该模型在超罕遇水准的地震作用下可以保持较大的屈服后刚度,因此其残余层间位移角很小(不超过0.028%),震后弧形角撑易更换;更换弧形角撑后,模型得到了一定程度的修复,但混凝土楼板开裂使得模型刚度未能完全恢复;在重复强震作用下,模型的最大层间位移角未发生显著变化,弧形角撑耗能稳定,但部分弧形角撑的最大变形有所增大,损伤在模型各局部呈现出不均匀发展的趋势。

In order to realize the rapid post-earthquake repair of steel frame structures,a moment-resisting frame with replaceable curved knee braces and high strength steel components was proposed.Under the target earthquake,the plastic deformation of the structure is concentrated on the curved knee braces,and the high-strength steel components remain essentially elastic to reduce the post-earthquake residual deformation.After the earthquake,the structure can be quickly repaired by replacing the curved knee braces.In order to investigate the seismic performance of the proposed structure and the practicability of replacing the curved knee braces,a 1/2 scale test model with concrete floor slabs was designed for shaking table test.The test results show that the test model realizes the predetermined damage control mechanism and can meet the maximum inter-story drift ratio requirements in GB 50011—2010‘Code for seismic design of buildings’.As the test model can maintain a large post-yield stiffness under the earthquakes exceeding the rare level,the residual inter-story drift is very small(less than 0.028%),and the curved knee braces are readily replaced.After replacing the curved knee braces,the test model is repaired to a certain extent,but the stiffness of test model is not fully restored because of the cracking of concrete floor slabs.Under repeated strong earthquakes,the maximum inter-story drift ratio of the test model does not change significantly.Curved knee braces dissipate energy stably,but the maximum deformation of some curved knee braces increases,and the damage shows an uneven development trend in various parts of the test model.