Experiments and Numerical Simulations on the Seismic Performance of Steel-Frame Composite Wallboard Shear Walls

In order to expand the applications of cold-formed thin-walled steel structures, this study proposes a new type of composite wallboard composed of cold-formed thin-walled C-shaped steel and multi-layer concrete, in which C-shaped steel serves as the skeleton, foam concrete acts as the thermal insulation material, and fine aggregate concrete and cement mortar play the part of envelopes. The composite wallboard can be made in a factory assembly line, meeting the requirements of the building (civil and structural) industry. Two steel-frame composite wallboard shear walls were subjected to reciprocating loading, with the connection mode as the design parameter, to investigate the seismic performance of the structure. The failure mode, hysteresis curve, skeleton curve, strength degradation, stiffness degradation, ductility, and energy dissipation capacity of the specimens were analyzed. On this basis, the finite element (FE) model of the steel-frame composite wallboard was established, and the model's accuracy was verified by comparing the bearing capacity and the skeleton curve. Results show that the structure shows shear failure characteristics, and the cement mortar layer and the fine aggregate concrete layer are separated from the C-shaped steel after being crushed. The infilled foam concrete is also crushed, and the welding seams between the extended C-shaped steel and steel frame of the WP-1 specimen are damaged. The hysteresis curves of the two specimens have a clear pinch, but the area enclosed by the hysteresis loop is large, and the energy dissipation capacity is also present. The yield load and ultimate load of the WP-2 specimen are higher than those of the WP-1 specimen, indicating that the higher the connection strength between the composite wallboard and the steel frame, the greater the ultimate carrying capacity of the specimen. The established FE model can accurately estimate the seismic performance of steel-frame composite wallboard shear walls.