Experimental Research on the Shear Performance of the Two-Storey Composite Cold-Formed Thin-Walled Steel Wall

The composite wall made of the cold-formed thin-walled steel has good shear performance. When it is used in buildings, its weak part is located at the joint of floors and becomes the first broken part under the action of the earthquake. The shear test of five Two-storey Composite Cold-formed Thin-walled Steel Walls (TCS) under cyclic loading has been carried out. The influences of axial pressures, types of anti-pulling bolts and panel materials on shear performances are examined. The results show that under the same working condition, the energy dissipation capacity of calcium silicate panel specimens is significantly lager than that of the gypsum panel specimens, and the ultimate bearing capacity is also greater. The axial pressure has a great influence on the ultimate bearing capacity and energy dissipation capacity of the specimens. Compared with the specimens designed according to the Ref. (JGJ227-2011, 2011), the energy dissipation capacity of all specimens is increased by 3.25 times. The extrusion between the self-tapping screw and the wall panel causes the screw to fall off, resulting in a sharp decrease in the rigidity of the specimens at the initial loading stage. After the failure of the wall panel, the bottom and top beam are restricted by double nuts of the anti-pulling bolt at the joint of floors, so the bearing capacity of specimens decreases slowly at the later loading stage. The tilt angle of anti-pulling bolt increases when the TCS wall is loaded to the later stage. The force state of the self-tapping screw on the hold-down is changed from bearing shear force to bearing tension and shear force, resulting in fast failure of the anti-pulling bolt suit. The load borne by the anti-pulling bolt suit is transferred to floor beams and their supporting stiffeners, causing them to collapse rapidly.