Out-of-plane resistance of concrete masonry infilled panels

Abstract

Nine large-scale concrete masonry infilled panels (3.6 × 2.8 m) were tested to destruction under uniformly distributed lateral pressure applied in small increments. Load–deformation curves of the infills and the enclosing steel frame showed linear elastic behaviour prior to first cracking. Nonlinear behaviour due to cracking and arching action of infill was prominent in the postcracking range. Parameters investigated experimentally included the effects of boundary supports, joint reinforcement, panel thicknesses, panel opening, and characteristics of construction. In parallel with the testing program, computer-aided analytical techniques were developed to predict the first crack and ultimate loads. First crack prediction was based on a finite element analysis for bending of thick plates, while ultimate load prediction was based on a yield-line technique modified to account for the arching action of infill confined within a flexible frame. Having been verified by comparison with test results, the postcracking analysis program was used to conduct a parametric study. It was found that infill compressive strength, panel dimensions, and frame rigidity have significant effect on ultimate loads. While central openings do not affect the ultimate strength, they do, however, reduce postcracking ductility. Key words: masonry, infill panel, steel frame, experimental, out-of-plane, behaviour, strength, arching, yield-line technique, cracking.