Shear response of masonry walls with external CFRP reinforcement

Abstract

In this study was characterized the shear behavior of full-scale masonry walls, externally retrofitted with carbon fiber reinforced polymers (CFRP), subjected to cyclic in-plane shear loads. Two configurations of reinforcement were studied: horizontally and diagonally oriented fibers (0° and 45º approximately with respect to the masonry courses, respectively). Twenty four clay-brick walls were tested: eight walls had horizontal steel shear reinforcement (RM), while 16 had no shear reinforcement (URM). Two walls had eccentric CFRP reinforcement (fibers bonded on only one side of the wall), and also two walls with special anchorage details of the CFRP reinforcement were tested. The effects of configuration and amount of CFRP reinforcement on the shear response were compared in terms of cracking, maximum strength, failure mechanism and displacement capacity.

The maximum strength of the URM walls increased in 50 to 80%, while for similar CFRP reinforcement ratios the maximum strength of the RM walls increased only 2 to 34%. All the walls showed large increase of deformation capacity, between 40 and 180%. The CFRP reinforcement produces a distributed pattern of cracks, with thinner cracks than the walls with no CFRP. Using more than one strip of CFRP reinforcement produces a less brittle failure, with residual strength, than using a single strip of CFRP reinforcement. The anchorage details were very effective in improving deformation capacity and failure mode of the walls. Finally, an expression to estimate the maximum strength is proposed.