自复位中心支撑钢框架结构抗震性能分析

Seismic performanceanalysis of self-centering concentrically braced steel frame structures

为了研究自复位中心支撑钢框架(SC-CBF)结构的抗震性能,对一四层SC-CBF结构进行了静力弹塑性分析、低周往复加载分析和动力弹塑性时程分析,并与中心支撑钢框架(CBF)结构进行对比,探究了不同GAP单元刚度和预应力筋截面积对SC-CBF结构自复位性能及抗震性能的影响规律。结果表明:与传统CBF结构相比,SC-CBF结构的抗侧能力强,地震作用下基底剪力小,卸载后的残余变形较小,具有良好的延性性能;在极罕遇地震作用下SC-CBF结构的位移响应大,耗散的能量多,层间位移角大而残余位移小,表现出良好的自复位性能和抗震性能;GAP单元刚度对预应力筋的受力性能影响较为明显,对结构的整体受力性能和延性性能影响较小,但结构的整体受力性能和延性性能受预应力筋截面积影响显著。

To study the seismic performance of self-centering concentrically braced frame(SC-CBF)structure,the static elasto-plastic analysis,low-cycle repeated loading analysis and elasto-plastic time-history analysis were conducted for a four-story SC-CBP structure,and compared with the traditionally concentrically braced frame(CBF)structure.The effects of different GAP element stiffnesses and cross-sectional areas of prestressed tendon were investigated on the self-centering performance and seismic performance of the SC-CBF structure.The results show that the SC-CBF structure has strong lateral resistance,a small base shear force under earthquake action and a slight residual deformation after unloading.The SC-CBF structure has a better ductility than the CBF structure.The displacement of the structure under the action of very rare earthquake is large,the structure dissipates more energy;the inter-story drift ratio is large and the residual displacement is small,exhibiting its desirable seismic behavior and self-centering performance;while the mechanical behavior of prestressed tendons is significantly affected by the stiffness of the GAP element.However,the overall mechanical and ductility performances of the structure are slightly affected by the influence of the stiffness of the GAP unit,the cross-sectional area of the prestressed tendons has a remarkable influence on the structural overall performance.