Numerical modelling of RC beams strengthened in shear using NSM FRP and cement based adhesives

Abstract

Cement based adhesives (CBAs) are currently emerging as a suitable replacement for epoxy resins in the strengthening of reinforced concrete (RC) elements using near surface mounted (NSM) fiber reinforced polymers (FRP). However, large scale experimental testing on RC beams strengthened in shear using NSM FRP and CBA has been limited to date and there is currently an absence of strength prediction models and design guidelines to enable engineers to design and detail such strengthening systems. This paper expands the theoretical understanding of RC beams strengthened in shear using NSM FRP and CBA using 2D finite element modelling by developing an experimentally validated modelling approach. Later, parametric studies into five concrete strengths (25, 32, 40, 45 and 50 MPa) and three FRP spacings (100, 150 and 200 mm) were conducted to generate a database of results which can later be used to inform the development of design guidelines. Data on maximum FRP strains at failure were combined with existing shear strength prediction models based on the modified compression field theory (MCFT) and national design standards to propose a strength prediction modelling approach.