T型件连接梁柱节点冲击试验研究和数值分析

Experimental and Numerical Study on Impact Behavior of T-stub Beam-column Connections of Steel Frames

设计采用了T型件连接的2个半刚性钢结构梁柱节点试件,对试件施加落锤冲击荷载来模拟结构的动态倒塌效应,考察T型件翼缘和腹板的厚度对钢框架梁柱节点抗冲击性能的影响.通过试验获得节点试件的破坏形态及其冲击荷载和位移时程曲线,分析试件冲击过程动态响应规律以及节点动态转角和耗能能力.试验结果表明:节点试件的主要破坏形态是节点核心区域的T型件的翼缘或腹板断裂破坏和受弯变形,以及钢梁腹板扭曲变形;2个半刚性连接的节点试件的抗冲击转动能力主要受制于T型件部位,且由于T型件构件承载力不足,其最大转角均未到达FEMA350标准倒塌控制转角限值(θ=0.109 rad)要求;T型件连接的半刚性节点相对普通全焊接的刚接节点的耗能能力和延性均有降低.采用ABAQUS软件建立了T型件连接梁柱节点子结构的有限元分析模型,通过分析T型件连接梁柱节点在冲击作用下内力发展规律可知,设计采用部分强度半刚性连接的T型件连接节点设计不利于构件向悬链线效应转换.

Two semi-rigid beam-column connection specimens with T-stubs of steel frame were designed.The impact tests using drop-hammer were conducted to simulate the collapse behavior under impact loading.The influence of thickness of T-stubs flange and web for the beam-column connection on the impact resistance of steel frame substructure was investigated.The failure modes and time histories of impact load and deformation were obtained,and the dynamic responses of the impact load and deformation time histories were analyzed as well as the dynamic rotation and energy dissipation of the substructures.Test results show that the failure modes of T-stub beam-column connection specimens mainly include the fracture and bending deformation of T-stub flange and web as well as distortional deformation of steel beam web.The rotation capacity of two connection specimens were dominated by the T-stubs,and their maximum rotations are less than the FEMA350 design limit(θ=0.109 rad)due to the premature failure of T-stubs.The energy dissipation and ductility of semi-rigid beam-column connection specimens with T-stubs are inferior to the ordinary welded rigid beam-column connections.The finite element(FE)analysis model of T-stub beam-column connection was established using ABAQUS software.The internal force development of specimens during the impact loading was analyzed and it demonstrated that the T-stub beam-column connection with design of partial strength and semi-rigid connection degraded the formation of catenary action.