Experimental and theoretical studies on the out-of-plane behavior of masonry strengthened with engineered cementitious composite

Abstract

Unreinforced masonry (URM) buildings are vulnerable to out-of-plane impacts. In this study, the authors adopted engineered cementitious composite (ECC) overlay as reinforcement to enhance the mechanical property of masonry walls in out-of-plane direction. For this purpose, 15 masonry wall specimens were fabricated and loaded to failure. The influences of ECC overlay thickness (10, 30, and 50 mm) and strengthening layouts (single-sided and double-sided) were highlighted. Comprehensive experimental investigations and theoretical analyses for the out-of-plane behavior of specimens were presented. The test results indicated that increasing the overlay thickness on the tensile side of wall can effectively improve the strength, deformability, stiffness and energy dissipation of masonry. More importantly, with the increase in overlay thickness, the failure modes of the strengthened walls were converted from flexural to flexural-shear and lastly to shear-bond slip. It is noted that the specimens that failed in flexural-shear exhibited superior overall performance, and excessive thickness of overlay may be detrimental to both ductility and energy dissipation. Moreover, flexural and shear analysis models were proposed to predict the strength of the strengthened specimens and calibrated by the test data.