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为研究板式连接中心支撑钢框架结构在水平荷载作用下的承载力、延性、结构影响系数、节点受力模式、屈服机制以及节点处梁柱附加弯矩分布规律,对两榀按1∶2.6缩尺的3层中心支撑钢框架进行了静力推覆试验。结果表明支撑失稳后楼层水平刚度明显降低,但由于人字形支撑受拉斜杆的存在,楼层能够维持足够的水平承载力。弹塑性层间侧移角远高于抗震规范要求,具有较大的延性系数和结构影响系数。支撑节点板附近的梁柱上存在附加弯矩,基于弹性极限状态,得到了附加弯矩指数的试验值。支撑端部深入节点板较多时,节点板在支撑失稳后以圆弧塑性铰线形式产生面外转动,仍具有高于支撑的极限承载力和塑性变形能力。结构屈服机制合理,体现为支撑屈曲或屈服在先,节点板屈服和梁柱屈服在后,符合抗震设计要求。
In order to study the load-bearing capacity, ductility, structural influence coefficient, node stress mode, yield mechanism and additional bending moment of beam-column joint under the horizontal load, Ruler 3-story center supported steel frame was a static pushover test. The results show that the horizontal stiffness of the floor is obviously reduced after the instability of support, but due to the presence of the diagonal bars, the floor can maintain sufficient horizontal bearing capacity. Lateral displacement of elastoplastic layer is far higher than the seismic code requirements, with greater ductility coefficient and structural influence coefficient. There is additional bending moment on the beam near the supporting gusset plate, and the experimental value of the additional bending moment index is obtained based on the elastic limit state. When the end of the support is deep, more nodal plates are formed, and the nodal plates rotate out of plane in the form of arc plastic hinge lines after the support is instability, and still have the ultimate bearing capacity and plastic deformation ability higher than the support. The yield mechanism of the structure is reasonable, which is manifested as the support buckling or yield yield, the yielding of the node plate and yielding of the beam and column, which meets the seismic design requirements.