装配式内置圆钢管混凝土异形柱-叠合梁框架中节点斜向加载抗震性能试验研究

Experimental study on seismic behavior of interior joints of assembled frames with special-shaped columns and composite beams under oblique loading

相对于工程轴斜向的地震作用是影响框架结构"强柱弱梁"破坏机制的重要因素之一。为研究装配式内置圆钢管混凝土异形柱-叠合梁框架中节点斜向地震作用反应,设计制作了3个足尺装配式中节点试件,并进行斜向45°加载。试验变化参数为轴压比(分别为0.2、0.3、0.4),通过水平低周往复荷载试验,分析其破坏形态、滞回性能、耗能能力、刚度退化等。结果表明:框架中节点破坏形态符合建筑抗震设计规范中"强节点、弱构件"的要求,节点安全可靠;轴压比为0.2~0.4时,随着轴压比的增大,试件承载力增大,延性提高;内置圆钢管混凝土的存在能够有效减缓刚度的退化速率;装配式内置圆钢管混凝土异形柱-叠合梁框架按照工程轴方向进行抗震设计可满足"强柱弱梁"破坏机制要求。

The oblique seismic action relative to the engineering axis is one of the important factors affecting the failure mechanism of the strong column and weak beam of the frame structure.In order to study the seismic performance of the interior joints of assembled frames with special-shaped columns and composite beams under oblique loading,three full-scale interior joint specimens were designed and fabricated,and the tests under oblique 45°loading were carried out.The parameters were axial compression ratios(0.2,0.3,0.4).The failure pattern,hysteretic behavior,energy dissipation capacity and stiffness degradation were analyzed through low cyclic loading test.Experimental results show that the failure mode meets the requirements of"strong joint,weak member".The joint is safe and reliable in a certain range of axial compression ratio(0.2-0.4).With the increase of axial compression ratio,the bearing capacity of the specimen increases and the ductility improves.The existence of concrete-filled circular steel tube can effectively slow down the degradation rate of stiffness.According to the axial direction of the engineering,the seismic design of the assembled frame with special-shaped columns and composite beams can meet the requirements of the failure mechanism of strong columns and weak beams.