用于RC框架-轻钢增层混合结构的露出式刚接节点抗震性能试验研究

Study on the seismic behavior of exposed rigid connection node for RC frame-mixed structure with adding light steels

上下部结构的连接节点是RC框架-轻钢增层混合结构抗震设计的关键所在,对两个上柱分别为工字形和箱形的露出式刚接混合节点进行低周反复加载试验,通过对比分析节点的破坏形态、滞回曲线、骨架曲线、强度退化、刚度退化、耗能能力,研究了RC框架-轻钢增层混合结构的上部结构截面形式的不同对露出式刚接节点抗震性能的影响。试验结果表明:两个试件均在混凝土梁根部发生剪切破坏,上部为箱形钢柱的节点,滞回环更为饱满,捏拢较少,承载能力、强度与刚度退化能力、等效黏滞阻尼系数、耗能能力等均优于上部为工字形钢柱的节点;保持下部结构不变,上部选用箱形钢柱,有利于提高节点的抗震性能。

The node of the upper and lower structure is the key to the seismic design of RC frame-mixed structure with adding light steels.Two exposed rigid connection nodes whose the upper columns are I-shaped and box shaped were tested under low cycle load reversals.Several indexes such as the failure modes,hysteretic curve,skeleton curve,retrogression of strength,rigidity degeneration and energy dissipation capacity of specimens were compared and analyzed to study the influence of the seismic behavior for RC frame-mixed structure with adding light steels with different section form of the upper structure.The results show that both specimens have shear failure at the root of concrete beams.For the node with box-shaped steel column,its hysteresis loop is more full and pinch phenomenon of hysteresis curve is less,its ability of delayed degradation of bearing capacity,strength and stiffness degradation,equivalent viscous damping coefficient and energy dissipation capacity are better than the node with I-shaped steel column.Keeping the lower structure unchanged,box shaped steel column for upper steel column is beneficial to improve the seismic performance of the node.