Cyclic behavior of double-skin composite walls with flat and corrugated faceplates

This paper presents the cyclic behavior of double-skin composite (DSC) walls for mid-to high-rise buildings, which consist of concrete filled steel tubes (CFTs), a pair of steel faceplates connected by tie bolts, and infill concrete. Four 1/3-scale DSC wall specimens, varying in faceplate profile and tie bolt spacing, were tested under combined axial and cyclic lateral loading. All specimens failed in flexure with a progression of steel tube frac-ture, steel faceplate buckling, and concrete crushing at wall bottom. The corrugated DSC walls and the flat DSC wall with standard bolt spacing were able to achieve an ultimate drift ratio around 3.4% and a ductility ratio greater than 5.4, while the flat DSC wall with bolt spacing 50% over code limit presented early faceplate buckling and undesired seismic performance. Compared to flat DSC walls, corrugated DSC walls, even with a doubled tie bolt spacing, had considerably higher initial stiffness, ductility ratio and energy dissipation. Formulations are proposed for predicting the lateral strength and drift capacity of corrugated DSC walls without elastic local buckling. The difference between the predicted and measured capacity for either lateral strength or drift is on average less than 6%.