型钢混凝土柱-混凝土梁混合节点抗震性能试验研究

为了研究强节点系数对型钢混凝土(SRC)柱-混凝土(RC)梁混合节点破坏形态的影响,对6个SRC柱-RC梁混合节点开展低周反复荷载试验。通过调整梁端纵筋配筋率和节点箍筋配置以构造不同的强节点系数,实现SRC柱-RC梁混合节点梁端弯曲破坏、梁端弯曲-节点剪切破坏和节点剪切破坏3种不同的破坏模式。在试验研究基础上,考察该类混合节点的滞回曲线、骨架曲线和各受力阶段变形特性。研究结果表明,强节点系数是控制SRC柱-RC梁混合节点破坏形态的重要参数,强节点系数小于1.1时,一般发生节点剪切破坏,应通过合理设计加以避免;由于柱型钢穿越节点核心区,增强了对核心区混凝土的约束,使得SRC柱-RC梁混合节点发生节点剪切破坏后的受力性能优于RC节点;通过对试验数据的分析,提出SRC柱-RC梁框架结构满足四个抗震性能水平的位移角限值。

EXPERIMENTAL STUDY ON SEISMIC BEHAVIORS OF SRC COLUMN-RC BEAM HYBRID JOINTS

Low cyclic loading tests were carried out for six SRC column-RC beam hybrid joints to investigate the effect of strength ratio of joint to beam ηj on the failure modes of specimens.The longitudinal reinforcement ratio of beam and stirrup ratio of joint area were adjusted to create different strength ratio of joint to beam and three different failure modes of specimens were achieved,which are flexural failure of beam,shear failure of joint and combination of both.Based on the experimental research,the hysteretic curves,skeleton curves and deformation behavior of specimens were studied.It is indicated that the strength ratio of joint to beam has great effect on the failure mode of specimens.When ηj of the specimen is less than 1.1,shear failure of joint area takes place,which should be avoided through proper design.SRC column-RC beam joints have better seismic performance than RC joints after shear failure of joint area because of the confinement of column steel,which is continuum through the joint area,to the concrete of joint core.Finally,a series of drift limit for the four different seismic performance levels were recommended.