In-Plane Cyclic Testing of Concrete-Filled Sandwich Steel Panel Walls with and without Boundary Elements

Concrete-filled sandwich steel panel (CFSSP) walls are composed of two steel skin plates interconnected by tie bars, with the space between the skin plates filled with concrete. These walls are attractive for use in seismic regions, but limited knowledge exists on their in-plane cycling inelastic flexural behavior. This paper reports results from an experimental study investigating this behavior by testing four cantilever CFSSP walls with and without circular boundary elements, having length-to-width ratios of 2.46 and 2.76, respectively. All of the tested walls were able to exceed their theoretical plastic moment capacity, calculated assuming a full plastic stress distribution of the cross section. The tested specimens exhibited stable ductile behavior up to 3% drift (and beyond in some conditions). Local buckling of the steel skin led to minor degradation in flexural strength. Fracture of the skin plates eventually developed as the ultimate failure mode. The effect of using different tie bars spacing to steel plate thickness ratios, and different techniques for welding the tie bars to the skin plates, are also addressed.