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Flexural Strengthening of Masonry Walls with External Composite Bars



K K. Bajpai, Dat Duthinh


The strengthening of epoxy with milled glass fibers allows full strength development of #2 glass FRP bars in 200 mm or half a concrete masonry unit length. This fiber-reinforced epoxy should be effective for other types of bars as well.With full anchorage assured, FRP bars provide an efficient method of strengthening masonry walls against out-of-plane bending. Three narrow (2.85 m H 0.40 m H 0.20 m), grouted, concrete masonry beams reinforced to 28 % of balanced ratio and four wide (2.85 m H 0.80 m H 0.20 m) beams reinforced to 41 % of balanced ratio were tested in four-point bending. All seven beams exhibited consistent flexural behavior, characterized by tensile failure of the reinforcement followed by crushing of the masonry at an average ratio of span to maximum deflection of 42.The ACI equations predict the flexural strength of these FRP externally reinforced concrete masonry beams with a comfortable factor of safety (mean = 1.36, coefficient of variation = 6 %). There was no difference in behavior between reinforcement parallel or perpendicular to the mortar bed joints. The unexpected shear failure of one FRP reinforced, ungrouted beam needs further investigation.
Proceedings Title
9th North American Masonry Conference
Conference Dates
June 3-4, 2002
Conference Location
Conference Title
Journal of The Masonry Society


anchorage, beam, bond, fiber-reinforced polymer (FRP), flexure, masonry, reinforced concrete, strengthening, wall


Bajpai, K. and Duthinh, D. (2003), Flexural Strengthening of Masonry Walls with External Composite Bars, 9th North American Masonry Conference, Undefined (Accessed July 20, 2024)


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Created July 31, 2003, Updated October 12, 2021