PSI - Issue 44

I. Boem et al. / Procedia Structural Integrity 44 (2023) 1260–1267 Boem I. and Gattesco N. / Structural Integrity Procedia 00 (2022) 000–000

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More discrepancies were noted in the samples strengthened at the intrados: in fact, it is observed that the simplified assumption of no slippage at the spring interfaces fitted quite good only in when considering the 1 st quadrant of the capacity curve of sample VRI-F (Fig. 4d). In fact, the numerical models (Fig. 8b) detected the opening of the spring interfaces, followed by a localized failure at the extrados at one haunch (masonry side) and a wider area with high strain level at the intrados of the opposite haunch (reinforcement side). The slip in the steel anchors started at about  h = 12-15 mm. The numerical curves revealed overestimations for sample VRI-F, 3 rd quadrant (Fig. 4d), and sample VRI-C (Fig. 4c): this supported the hypothesis of some inward drift at the spring sections, neglected in the models. 5. Conclusions The effectiveness of two techniques, CRM and FRCM, in the strengthening of thin masonry vaults were investigated experimentally, through transversal cycling loading tests. The application of the reinforcements at the extrados resulted very effective and almost comparable for the two techniques, with an increase of resistance of about 20 times in respect to the plain masonry and also very high displacement capacity (around 100 times greater). Slightly lower performances were attained in case of reinforcement at the intrados, with increases of about 15 times in terms of resistance and of about 90 times in terms of ultimate displacement. But, in this case, the displacement capacities can be reduced by 70% or more, in case slippage at the spring sections. The first numerical results coming from the application of a multi-layer model on the strengthened vaults were presented (nonlinear-static analyses). The simulations resulted capable to catch the general behavior of the samples, in terms of capacity curve and failure mechanism, even though based on a smeared crack approach and a rather coarse meshing. However, some discrepancies emerged in the samples strengthened at the intrados, likely for the neglecting of possible inward drifts at the spring sections. Further numerical investigations are in progress to check the sensitiveness of the models and to study different geometries and load patterns. Acknowledgments The experimental tests were part of a research project funded by Fibre Net SpA (Pavia di Udine, I) and were carried out in conjunction with the researchers of the University of Trieste (I). The numerical study is part of a research project funded from the EU’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 101003410. The help of prof. B. Patzák and prof. A. Kohoutková (CTU, Prague, CZ) is gratefully acknowledged. 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