PSI - Issue 11

Francesca Giulia Carozzi et al. / Procedia Structural Integrity 11 (2018) 355–362 F.G. Carozzi et al. / Structural Integrity Procedia 00 (2018) 000 – 000

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again up to 32 kN and a maximum displacement of 7.5 mm was reached before the complete collapse. Fig. 5b shows the load-displacement curves for the reinforced samples up to the peak load, to compare the behavior in the first phases, the end of the elastic phase and the non-linear increment of the load up to the maximum one. In Fig. 5c the comparison between all the results is reported. The applications of G-TRM and cG-TRM systems provide a higher peak load, equal to 3.5 and 4 times the one of the control specimen respectively. The G-TRM sample presented a limit of the elastic phase at a load equal to 90.7 kN and a non-linear phase characterized by the appearance of the first cracks up to the maximum load. The decreasing phase is caused by the opening of the main diagonal cracks, with the slippage and rupture of the filaments in the glass yarns. The cG-TRM sample showed a similar behavior, even if the non-linear increasing phase presented a higher stiffness. During the cracking phases the displacement reached values of about 5 mm, after that the sample collapsed due to the opening of a main crack and the tensile failure of the fiber grid. The G TRM-NSM wall reached a maximum load equal to 1.7 times the un-reinforced one. The load-displacement curves showed the different behavior with respect to the two faces that present two different reinforcement systems. The side reinforced with the G-TRM material presented an elastic phase with higher stiffness and reached a lower displacement at the peak load both in the tensile and compressive diagonals. The side reinforced with the Near Surface Mounted system failed to the diagonal crack of the vertical and horizontal mortar joints. In Fig. 6 the failure modes are represented.

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b c Fig. 5. Load-Displacement curves: a) DW_control sample; b) DW_cG-TRM, DW_G-TRM, DW_G-TRM-NSM (up to peak load); c) comparison between the four samples