Investigating the effect of stiffness of non-structural walls consisting of panels with polystyrene core and lightweight concrete coating in infill-steel frame interaction

This paper investigated the effect of the stiffness of a light panel type with polystyrene core and lightweight concrete coating on the behavior of plain steel frames. An experimental study was performed on two large-scale specimens of one-story single-span. The behavior of panels and determine the effect of their stiffness, an in-plane infill-frame interaction frame, including a steel frame with isolated and non-isolated panels, were investigated. The specimens were tested under controlled displacement to investigate the in-plane infill-frame interaction of steel frames. Both isolated and non-isolated panels were tested under quasi-static cyclic loading. The results show that the proper behavior of this type of panel in isolated and non-isolated frames, the global stiffness of the frames and panels are reduced with a gentle slope, and brittle failure does not occur in the frames and panels. In the isolated specimens, the relative displacement (drift) of 1%, and the stiffness was 1.22 kN/mm. When the drift increased to 2.5%, the stiffness decreased to 0.88 kN/mm. In the non-isolated specimens, the drift of 1%, and the stiffness was 2.49 kN/mm. When the drift increased to 2.5%, the stiffness decreased to 0.89 kN/mm. The behavior of the non-isolated frame after loading is similar to the isolated frame because only the corners of the panel failed. A similar result was obtained in the failure pattern. In other words, the corners of the non-isolated panels attached to the frame failed by increasing the displacement due to in-plane infill-frame interaction. In the subsequent cycles, another part of the corners of the panels failed again. Complete failure was not observed in the panels. Similarly, in the non-isolated specimens, the panels remain without global failure after applying the cyclic load. The behavior of the non-isolated frame is similar to the isolated frame, with a decreased stiffness.