Numerical and experimental study of GFRP-masonry interface behavior: Bond evolution and role of the mortar layers

Bond behaviour of Steel Reinforced Polymer strengthening systems

“…14b) and the strain field (Fig. 14b) on brickwork clearly show that the inhomogeneity of the substrate induces a strongly uneven strain distribution, with a periodic variation related to the alternation of brick units and mortar joints [41,42]. Stress transfer is concentrated at the brick surface, while it strongly reduces at the bed joints, due to the lower stiffness of the mortar with respect to the brick.…”

Experimental bond tests on masonry panels strengthened by FRP

“…Detailed knowledge of the interface behaviour allows to perform an accurate numerical analysis, where between the FRP reinforcement and the masonry substrate can be placed a cluster of zeroethickness interface elements [40,41] characterized by the analytical laws calibrated as described.…”

A review on the bond behavior of FRP composites applied on masonry substrates

“…Nevertheless, when load-slip curves coming from bond tests on bricks and on masonry prisms are compared, a significant difference can be found between these two types of substrates. In fact, experimental curves obtained from masonry prisms presented several discontinuities or jumps during the debonding part of the tests, with a typical saw-tooth shaped curve, where load drops are associated with the periodic alternation of bricks and mortar joints on the substrate [10,27,[44][45][46]. This particular behavior was mainly observed analyzing load-slip curves and confirmed by local strain gauges readings during tests execution; several numerical models [39,44,[47][48][49] were then developed in order to validate experimental outcomes and to better understand this phenomenon, assuming different interface laws for bricks and mortar joints.…”

“…Results of interface laws calibrations can be found in different studies [9, 13-16, 19, 23-25, 27, 41, 55] and have been very useful as a first step to define parameters for performing accurate numerical analyses [44,[56][57][58][59], even at larger scales. Fig.…”

“…A different numerical FE model, described in [44], was developed making use of two different interface laws in order to evaluate the role of mortar joints (Fig. 5).…”