基于性能设计的高强钢组合Y形偏心支撑钢框架抗震性能研究

RESEARCH ON THE SEISMIC BEHAVIOR OF Y-TYPE ECCENTRICALLY BRACED FRAMES COMBINED WITH HIGH STRENGTH STEELS BASED ON PBSD METHOD

Y形偏心支撑钢框架结构中耗能梁段置于框架梁之外,耗能梁段变形不会对主体结构和楼板造成损害,震后易于修复更换。为了保证耗能梁段充分发挥塑性变形进行耗能,非耗能构件（框架梁、框架柱）截面设计往往过大,浪费钢材且限制了偏心支撑钢框架的应用。高强钢组合偏心支撑框架结构是指耗能梁段采用普通钢材（Q345钢）,而框架梁、柱等非耗能构件采用高强度钢材（如Q460）,不仅有效减小构件截面,而且可以推动高强钢在抗震设防区的应用,经济效益显著。采用基于性能的抗震设计方法设计了5层、10层、15层和20层的Y形偏心支撑钢框架结构,算例模型包括高强钢组合Y形偏心支撑钢框架和传统普通钢Y形偏心支撑钢框架,通过Pushover分析和时程分析研究该结构形式的承载力、抗侧刚度、层间侧移分布及破坏模式。研究表明：相同设计条件下,高强钢组合Y形偏心支撑钢框架结构与普通钢Y形偏心支撑钢框架结构的承载能力相近,但抗侧刚度略低,罕遇地震作用下二者具有相似的层间侧移分布和破坏模式。

The link beams of Y-type eccentrically braced frames（ Y-EBFs） are outside of beams,so the deformation of link beams do not cause damage to major structure and slabs,it is easy to repair and replace after earthquake. The sections of frame members（ such as beams or columns） are often designed too large to ensure the plastic deformation of link beams to dissipate energy sufficiently,however,the approach not only waste steel,but limit the application of eccentrically braced frames. The structure of Y-type eccentrically braced steel frames with high-strength steel（ YHSS-EBFs） consists of link beams and braces composed of Q345 steel rather than the HSS（ Q460） used in other members（ columns and beams）,which are non-energy-dissipation members. The use of HSS effectively could reduce the cross section of the members and result in increased economic efficiency,four groups of both Y-HSS-EBFs and YEBFs were designed by performance-based seismic design（ PBSD） method,which including 5-story,10-story,15-story and 20-story structures. The nonlinear Pushover analysis and nonlinear dynamic analysis were conducted,and the bearing capacity,lateral stiffness,story drift and failure mode under rare earthquake between Y-HSS-EBFs and Y-EBFs were compared. The results indicated that Y-HSS-EBF had similar bearing capacity with Y-EBF while the lateral stiffness of Y-HSS-EBF were lower than that of Y-EBF. Y-HSS-EBF and Y-EBF designed by PBSD method had similar failure mode and story drift distribution under the rare earthquake.