冷成型钢龙骨-覆面板材自攻螺钉连接力学性能试验研究

Experimental study on mechanical behavior of cold-formed steel stud-to-sheathing screw connections

冷成型钢复合剪力墙是冷成型钢结构体系的主要抗侧构件,其受力性能与轻钢骨架-覆面板材自攻螺钉连接的受剪性能密切相关。对36组冷成型钢龙骨-波特板自攻螺钉连接进行抗剪试验,分析了板材类型、螺钉边距和螺钉数量等因素对其受力性能的影响。研究结果表明:自攻螺钉连接件单向受拉时均发生了板材的脆性破坏,而单向受压时连接件破坏呈延性;板材类型、螺钉数量和加载方式对连接件的峰值荷载具有显著影响,中密度波特板连接件的峰值荷载比低密度波特板连接件的峰值荷载高48%~95%,单根自攻螺钉连接件的峰值荷载比多根自攻螺钉连接件中单颗螺钉的峰值荷载高约30%;剪力垂直于螺钉边距方向且单向受拉工况下,螺钉边距对连接件峰值荷载的影响较大,螺钉边距每增加5 mm,连接件峰值荷载增加约30%;单向拉伸工况、剪力平行于螺钉边距方向时,连接件的峰值荷载和峰值位移较大;采用Foschi指数函数模型拟合连接件的骨架曲线,与试验结果吻合较好,为冷成型钢结构体系数值模拟研究提供了连接件性能基本参数。

The mechanical behavior of cold-formed steel(CFS) framed composite shear wall, which is the main lateral force resistance assembly of CFS structure, is closely associated with the shear behavior of screw connections between steel studs and sheathing boards. Shear experiments were performed on 36 groups of screw connections. The effects of various factors such as sheathing type, edge distance and number of screws on the mechanical performance were considered. The experimental results showed that the brittle failure of screw connections occurs when screw connection specimens are in uniaxial tension, whereas the ductile damage happens under monotonic compression. The plate type, screw number and loading mode have significant effects on peak loads of connections, in which, the peak loads of screw connections with medium-density calcium-silicate board are 48%-95% higher than those with low-density calcium-silicate board. And the peak load of single screw in single screw connections is about 30% higher than that in multi-screws connections. Under the condition of monotonic tension as well as the shear perpendicular to the direction of edge distance, the peak loads of screw connections increase by about 30% with every 5 mm increase of the screw edge distance. Under monotonic tension, the peak loads and peak displacements of specimens are higher than other cases when the shear is parallel to the direction of edge distance. The skeleton curves were fitted by ‘Forschi’ exponential model, which are in good agreement with the experimental results and can be used as the basic parameter of screw connections in the numerical study of CFS structures.