高强螺栓端板连接钢梁-方钢管混凝土框架结构抗震性能研究

通过一榀高强螺栓端板连接的2层1跨半4∶7比例组合梁-方钢管混凝土模型框架的拟动力试验、拟静力试验和静力推覆试验,运用子结构方法,模拟了一榀10层3跨的平面框架,研究了钢管混凝土框架结构的破坏形态、位移响应、滞回特性和耗能等抗震性能。拟动力试验中,多遇烈度地震时,框架刚度降低很小;基本设计烈度地震时,框架刚度降低约13%;罕遇烈度地震时,框架刚度降低20%,框架层间位移角小于2.0%。拟静力试验中,最大层间位移角超过1.6%,部分构件出现初始局部屈曲,框架整体未出现强度退化。在静力推覆试验中,即使层间位移角超过6.0%,框架承载力仍未发生下降。高强螺栓端板连接节点能够满足抗震设计要求,在规范限定的按弹塑性设计的层间位移角限值范围内,经过合理设计的螺栓端板连接可视为刚性连接。试验结果验证采用螺栓连接的钢梁-方钢管混凝土框架具有良好的抗震性能,可在抗震设防区结构中推广使用。

Seismic behaviors of high-strength bolted end-plate connected composite steel beam and square concrete filled steel tube column frames

Utilizing sub-structure methodology,pseudo-dynamic tests, a quasi-static test and a static pushover test were conducted on a two-story and one and a half bay frame, with composite steel beams and concrete filled steel tube (CFT) columns connected by high-strength bolts and end plates. The 4∶ 7 scale sub-assemblage frame simulated a portion of a 10 stories and 3 spans plane frame. Seismic performance of the CFT composite frame including failure pattern, displacement response, hysteretic behavior and energy dissipation capability were investigated. During pseudo-dynamic test, the stiffness of tested frame had little degradation for frequent occurrence earthquake, and the stiffness dropped by about 13% for design basis earthquake, and the stiffness reduced 20% however the story drift ratio was less than 2.0% for maximum considered earthquake. Initial local buckling at beam and first story column ends was detected after the story drift ratio exceeding 1.6% during pseudo-static test, while no global strength degradation occurred. Even when the story drift ratio exceeding 6.0% during pushover test, the frame could still develop sufficient lateral loading capacity. The high-strength bolted end-plate connections satisfied the requirements of aseismic design and were suggested to be designed as rigid connections within the drift limitation of related code. It is validated that the moment resistant frame with steel beams bolted to CFT columns can provide excellent seismic behaviors and has the potential to be utilized in buildings in earthquake regions.