梁端铰接钢管混凝土框架-核心筒结构的减震研究

Study on seismic reduction of CFST column-pinned steel beam-RC core tube structures

梁端铰接钢管混凝土框架-核心筒结构很好地解决了传统双重抗侧体系由于节点焊接而带来的系列问题,但不可避免地对结构抗震性能产生影响,因此,亟需针对此类结构的消能减震研究。本文以30层梁端铰接的钢管混凝土柱-混凝土核心筒结构为研究对象,通过引入不同构造形式的消能黏滞阻尼伸臂形成减震层,利用OpenSees有限元软件对结构进行弹塑性时程分析,优选出最佳构造形式,并据此对比设置一道及两道减震层时,结构在罕遇地震下减震性能及黏滞阻尼器的阻尼系数和速度指数变化对设置一道减震层结构抗震性能的影响分析。研究结果表明:竖向斜撑型减震层对结构顶点位移、层间位移角、基底剪力的控制效果及自身的耗能效果最佳,而两道减震层结构的综合性能要略优于一道减震层结构,但一道减震层结构对减震层位置变化更敏感,且当减震层位于结构1/3 H层高时减震效果最佳;阻尼系数与速度指数过大或过小均会对结构产生不利影响,而速度指数能有效降低结构的层间位移角,但应注意所带来的位移突变和基底剪力增大问题。

A series of issues,caused by the welding of traditional dual lateral force resisting system,can be effectively solved by CFST(concrete-filled steel tube)column-pinned steel beam-RC(reinforced concrete)core tube structure,however,new problem would be generated that it unavoidably affects the seismic performance of the structure.Therefore,there is an urgent need for research on energy dissipation and seismic mitigation specific to this type of structure.This paper focuses on a 30-story CFST column-pinned steel beam-RC core tube structure.By introducing damping layers with different construction forms to form energy dissipation mechanisms,the seismic performance of the structure is investigated.Elastic-plastic time history analysis is conducted using the OpenSees finite element software.The optimal structural form of the damping layer was evaluated and determined,and which is adopted to investigate the seismic reduction performance of the structure under rare earthquakes with one and two damping layers,as well as the influence on the seismic performance of the one-damping-layer structure with variable damping coefficient and velocity exponent of the viscous damper.The results show that damping layer in the form of vertical inclined bracing exhibited the best control effect on the structure's top displacement,inter-story drift ratio,and base shear,while also demonstrating superior energy dissipation capabilities.The comprehensive performance of structures with the two damping layers is slightly better than that of the one damping layer,while structures with the one damping layer is more sensitive to the variation of the location of the damping layer,and the seismic reduction of structures is the best when the damping layer is located at 1/3 height of the structure.Moreover,excessively large or small damping coefficients and velocity exponent would have adverse effects on the structure,and the velocity exponent could effectively reduce the drift ratio of the structure.However,more attention should be given to potential issues such as sudden displacement changes and increased base shear force.