工厂加工制作的特殊构造梁柱节点抗震性能试验研究

Experimental study on seismic performance of specifically pre-fabricated beam-column connections

为研究工业用途的某特种钢结构的抗震性能,选取其中3个特殊构造梁柱节点,即柱强轴方向带悬臂梁段的端板螺栓节点(试件I)、柱强轴方向有梁的弱轴方向异型盖板焊接节点(试件II)、柱强轴方向无梁的弱轴方向异型盖板焊接节点(试件III),制作足尺试件,进行循环荷载作用下的拟静力试验,研究端板连接、空间加载制度以及特殊的构造形式对节点破坏形态、承载力、塑性转角、延性及耗能能力的影响。试验结果表明:3种形式节点试件的梁端最大塑性转角均能达到0.025 rad,位移延性系数大于4.0,累积塑性转角可达最大塑性转角的20~30倍,承载力可达到梁全截面塑性承载力的1.0~1.3倍;试件II的最大层间位移角达到0.035 rad,最终因梁中发生局部屈曲而破坏,而试件I和试件III的最大层间位移角可达0.040 rad,满足美国钢结构抗震设计规范中对特殊抗弯钢框架梁柱节点转动能力的限值要求,破坏形态分别为螺栓拉断、盖板出现延性开裂。研究结果表明,试件II和试件III抗震性能良好,试件I因端板螺栓连接承载力不足,导致其耗能能力较差,因此需从设计上加以改进。

Three types of specifically pre-fabricated steel beam-column connections used in a special industrial steel structure were fabricated in full-scale,including the bolted end-plate connection with a short cantilever beam in the strong-axis of column( specimen I),the spatial weak-axis connection with a beam welded in the strong-axis of column( specimen II) and the planar cruciform weak-axis connection( specimen III),and then quasi-statically tested under cyclic loading to study their seismic performance and investigate the influence of bolted end-plate connection,spatial loading protocol and specific configuration details on the failure mode,ultimate capacity,plastic rotation,ductility and energy dissipation. The test results show that the plastic rotation of all the specimens exceeds 0. 025 rad,and accumulated plastic rotation is 20 to 30 times larger than the maximum plastic rotation with a ductility coefficient greater than 4. 0. The measured flexural resistance of the specimens determined at the column face reaches 100% to130% of the full plastic moment resistance of the connected beam,and the maximum story drift angle reaches 0. 035rad for specimen II which finally fail by local buckling in the beam,and reaches 0. 040 rad for specimen I and III which fail by tensile failure of the bolt and ductile fracture in the cover plates respectively,and both satisfy the requirements for special moment frames in AISC Seismic Provisions. Specimen II and III are effective to guarantee the adequate capacity of consuming energy and ductility under seismic force,while the seismic performance of specimen I is relatively poor due to inadequate loading capacity of the bolted end-plate connection and should be improved in the view of design.