Out-of-plane behavior of surface-reinforced masonry walls

Abstract

This paper presents the results of an experimental program designed to evaluate the out-of-plane shear strength of masonry wall system; and to evaluate of the influence of the area of externally bonded FRP composites on the shear strength of the system. Eighteen compact masonry wall panels (3′×2′×8″, 900×600×200 mm) were tested for static out-of-plane loads. Nine panels were reinforced by one layer of WEB ‘S-Glass’ fiber-reinforcing system attached to the tension side of the wall, while the remaining nine were reinforced with two layers of composite overlay on the tension side. The influence of the overlay's embedded length (the distance between the support and the overlay's end) on the shear strength was also investigated. The variables evaluated included three layout configurations and two reinforcement ratios. Three different distances between the overlay end and the adjacent support were tested, 0, d/4 ( d is the block unit thickness) and d/2. Both one and two layers of WEB fibers were used and three specimens were evaluated for each variable. An MTS machine was used to test each panel under four-point load conditions. The failure loads, mid-span deflection, fiber-end slippage and failure modes were recorded. Based on the results of the experimental program, it appears that the out-of-plane shear strength of the concrete masonry wall systems is constant over the range of variables tested. The measured shear strength of the masonry wall specimens evaluated in this program indicates that the code defined shear strengths may not be as conservative as assumed.