Influence of textile reinforced mortars strengthening on the in-plane/out-of-plane response of masonry infill walls in RC frames

In existing Reinforced Concrete (RC) buildings, the out-of-plane (OOP) collapse of masonry infills can be a significant issue for resulting damage and life safety in case of earthquake. Quite recently, research works from the literature have studied possible strengthening strategies to reduce the vulnerability of the infill panels due to OOP loading. Among these techniques, the use of Textile Reinforced Mortars (TRM) as an innovative reinforcing plater has rapidly become very popular, due to its good compromise between costs of intervention and effectiveness, along with its durability properties. Nevertheless, still quite few studies exist on this topic to experimentally prove the TRM effectiveness on masonry infills, above all in case of pre-existing in-plane (IP) damage. Even fewer studies in the literature are currently devoted to the prediction of the OOP strength of TRM-strengthened infills, despite the necessity to quantify the beneficial effect of the strengthening solution in a force-based safety check. This work shows the experimental outcomes of four full-scale infilled frames under OOP loading, with or without a TRM-based strengthening technique and with or without previous IP damage. First, a look insight the effect on dynamic properties of the TRM strengthening strategy is reported and commented. Then, the (cyclic) IP and (half-cyclic) OOP pseudo-static testing results are shown and compared to each other to analyze the effect of the IP damage on the OOP response with and without strengthening. Lastly, the very few predictive proposals for OOP strength of TRM-strengthened specimens have been analyzed, based on a dedicated collected database, to lastly provide some suggestions for future design tools for TRM applications on infills.