Modelling single-lap shear tests on masonry elements strengthened by FRCM

Fiber Reinforced Cementitious Matrices (FRCM) are composite materials adopted nowadays for the structural strengthening of masonry structures to improve the seismic behavior. To guarantee the efficiency of the strengthening system, a proper bond between the FRCM and the masonry substrate should be ensured. For the mechanical characterization of the composite materials, indeed, bond tests are performed together with tensile tests. In the present work, numerical simulations of single-lap shear tests on carbon FRCMs applied on a brick masonry substrate are performed with the objective of calibrating a proper bond-slip law. In particular, the carbon fibers are singularly modelled, adopting a micro-modeling approach for the FRCM system. Nonlinearities are lumped into interface elements at the matrix-to-fiber interface, to reproduce the failure modes typically encountered in experimental tests, where a relative slip between the fibers and the matrix can often occur. Comparisons between numerical results and results obtained from experimental tests performed on the same FRCM systems, allowed for the calibration of bond-slip laws, which could be also implemented in the numerical modeling of experimental tests on full-scale strengthened masonry walls.