高强钢组合K形偏心支撑钢框架抗震性能分析

ANALYSIS OF ASEISMIC PERFORMANCE OF HIGH STRENGTH STEEL COMPOSITE K-ECCENTRICALLY BRACED FRAMES

为了合理评估高强钢组合K形偏心支撑框架(K-HSS-EBFs)的抗震性能,首先建立了振动台试验试件的有限元模型,验证了有限元分析方法的适用性。设计了一个10层K-HSS-EBF结构,选取10条地震记录对其进行增量动力分析(IDA)。探讨了在强震作用下结构的薄弱部位、耗能梁塑性区的形成和发展、基底剪力和最大层间位移的关系,得到了结构概率分位值为10%、50%和90%的IDA曲线以及位移延性系数,结合定义的性能参数评估了结构的抗震性能。研究表明:随着地震动峰值加速度的增加,各层耗能梁先后进入塑性,并逐渐发展,吸收地震能量;K-HSS-EBFs的易损曲线能很好地反映其抗震性能;按《建筑抗震设计规范》设计的高强钢组合K形偏心支撑框架偏保守,能承受远大于设防烈度的地震作用,造成结构设计的浪费。

To evaluate the aseismic performance of high-strength steel composite eccentrically braced frames(K-HSS-EBFs), a finite element analysis of a shaking table test specimen was carried out. The simulated results are consistent with the test results, which proves the feasibility of the finite element method. A ten-story K-HSS-EBF was designed, and incremental dynamic analysis(IDA) was carried out with 10 seismic ground motions. The weak parts of the structure, the formation and development of the plastic zones of the link and the relationship between the base shear force and maximum story drift under the action of strong earthquakes were researched. The IDA curves of 10%, 50% and 90% fractiles and the displacement ductility coefficient were ascertained. The aseismic performance was assessed by combining it with the defined performance parameters.The results show that with the increase in the peak ground acceleration, the links successively entered the plastic state and absorbed the seismic energy. The collapse fragility curve can reflect the aseismic performance of the K-HSS-EBFs. The K-HSS-EBFs designed according to the current seismic code have the negligible risk of collapse and high security reserve, which will cause the waste of structural design.