装配式混凝土梁柱半刚性节点的抗震性能

Seismic behavior of semi-rigid joints of precast concrete beam and column

为研究装配式混凝土框架节点的抗震性能,提出一种端板螺栓连接梁柱节点形式,设计节点试件并对其进行拟静力试验研究,与现浇混凝土框架节点试验进行对比,考察试验节点的破坏形式、承载能力以及耗能能力和位移延性等抗震性能指标;采用有限元程序模拟试验节点试件的受力性能,验证模型的准确性。结果表明:现浇节点试件以梁端截面形成塑性铰耗能,破坏时梁端截面发生弯剪破坏,柱和节点均出现裂缝;端板螺栓连接半刚性节点试件主要以梁柱之间发生相对转角耗能,最终由于梁端截面混凝土材料强度不足而发生破坏,而柱保持完好,可通过更换高强螺栓和预制梁快速修复节点;提出的端板螺栓连接节点可以满足钢筋混凝土结构的耗能和延性要求,梁内钢筋、预埋的端板和混凝土是否能够协同工作对节点的受力性能有较大影响。

To examine the seismic behavior of semi-rigid joint of the precast concrete frame,a type of beamcolumn joint connected by end-plate and bolts is proposed.The joints are designed and the quasi-static test is carried out,and compared with the test of cast-in-place concrete frame joint.The failure mode,bearing capacity,energy dissipation capacity and displacement ductility of the joints are investigated.The finite element program is used to simulate the mechanical performance of test joints,and the accuracy of the model is verified.The results show that the cast-in-place joints dissipate energy by the plastic hinge at the end of the beam,and the section at the end of the beam is damaged by bending and shearing.The cracks are found in both the column and the beam.The semi-rigid joint connected by end-plate and bolts mainly dissipates energy through the relative rotation between the beam and the column.Its failure is due to the insufficient strength of the concrete at the end of beam,but the column and its internal reinforcement remain intact.Consequently,the joint can be quickly repaired by replacing high-strength bolts and precast beam.The joint connected by end-plate and bolts can meet the requirements of energy dissipation and ductility of reinforced concrete structure.Whether the reinforcement and embedded end-plate in the beam can work together with concrete has great influence on the mechanical performance of the joint.