Shear-transfer mechanisms in reinforced concrete beams with GFRP bars and basalt fibers

Abstract

An increase in the use of glass fiber reinforced polymer (GFRP) bars and discrete fibers in reinforced concrete structures, associated with the limited understanding of the shear behavior of concrete beams, highlights the need for a comprehensive study of various force transfer mechanisms. This article investigates the experimental behavior of four slender reinforced concrete beams with GFRP bars. The testing program includes beams with and without GFRP stirrups and dispersed basalt fibers in the concrete matrix. The displacement fields throughout the shear span were monitored according to the digital image correlation (DIC) technique and shear-transfer constitutive models from the literature assessed the contribution of each mechanism. The sum of such contributions consistently agreed with the experimental shear strength and the use of fibers in beams with GFRP stirrups modified the relative influence of both shear reinforcements, i.e., one of them can preponderate over the other in function of load stage and failure mode.