Dry masonry strengthening through basalt fibre ropes: Experimental results versus out-of-plane actions

Monolithic behavior is one of the most important characteristics that historical masonry should have. Without this basic feature, in fact, no structural analysis could be considered reliable. If this characteristic is absent, strengthening the bearing masonry – by giving it a transversal monolithic behavior - is one of the first retrofitting actions to undertake in order to improve the seismic performance of the masonry. Hence, the idea to develop a new consolidation technique especially formulated for historical masonry. Stitching masonry through continuous flexible elements is an innovative technique that enables the connection of several masonry components. Moreover, thanks to these flexible elements it is possible to attribute stitching masonry a monolithic behavior according to the principles that govern the intervention on existing buildings: minimal intervention, compatibility, reversibility, respect of authenticity, matter conservation, control of the visual impact and possibility of recognizing the intervention. 4 mm basalt fibers ropes of nominal diameter (declared by manufacturer), have been used in this experimental program as continuous flexible elements. The technique has been already tested and proved to be effective in improving the behavior against in-plane actions. Good results have been obtained also by excluding synthetic adhesives (resins), with an enhancement about reversibility. This paper presents the results of an experimental campaign that evaluates effective techniques against out-of-plane loads. Reinforced and unreinforced brick masonry specimens have been tested by simulating vertical bending mechanism activation to evaluate the stitches contribute.