冷弯薄壁型钢结构体系中自攻螺钉连接的抗剪性能试验研究

Experimental study on shear behavior of screw connections in cold-formed thin-wall steel structures

为了研究钢板与钢板、钢板与定向刨花板(OSB板)以及钢板与硅酸钙板(CSB)之间(自钻)自攻螺钉连接的抗剪性能,对32个螺钉连接试件进行了试验研究,研究了螺钉连接试件的受力过程和受力模式,分析了钢板厚度、板材受拉纤维方向的差异、加载速度以及螺钉至板材边缘距离等参数对试件受剪承载力的影响.试验结果表明:钢板与钢板连接的破坏形态为螺钉孔处钢板局部承压和螺钉头被剪断;钢板与OSB板连接最终发生自攻螺钉的过度倾斜和OSB板端部的劈裂分层;钢板与CSB板连接的破坏模式为自攻螺钉处CSB板被净截面拉断.随着钢板厚度以及螺钉至板材边缘距离的增加,自攻螺钉连接的受剪承载力有所提高;随着加载速度的增加,钢板与钢板连接以及钢板与CSB板连接试件的受剪承载力略有增加,钢板与OSB板连接试件的受剪承载能力出现一定降低.OSB板与CSB板的方向性导致纵向纤维受拉试件的受剪承载力明显高于横向纤维受拉试件.

In order to investigate the shear behavior of the screw connections between steel and steel, oriented strand boards （OSB） or calcium silicate boards （CSB）, a total of 32 specimens of screw connections were tested. The loading process and failure modes were analyzed. The factors such as steel plate thickness, the direction of tension fiber, loading rate and the distance between the center of the screw and the adjacent edge of the sheathing, which influence the shear capacity, were researched. The results indicate that the failure modes of connections between steel and steel are the local compression of screw holes and the shear fracture of screw heads. Screw connections between steel and OSB sheathings happened to the inclination of screws severely and the splitting of the edge of sheathings. The damage phenomena of screw connections between steel and CSB sheathings are the tensile failure of the net section of CSB sheathing on the location of the screw. With the increase of steel plate thickness and the distance between the center of the screw and the adjacent edge of the sheathing, screw connections have larger shear capacity. With the increase of the loading rate, the shear capacity of screw connections between steel and steel or CSB sheathings could be strengthened, but screw connections between steel and OSB sheathings have lower shear strength. Owing to the direction of tension fiber of OSB and CSB sheathings, the perpendicular-to-grain loaded connections may give lower shear capacity compared with the parallel-to-grain loaded connections.