Abstract

nnovative strengthening solutions, such as Fiber Reinforced Cementitious Matrix (FRCM), are becoming increasingly diffused for the retrofitting of existing masonry structures with the aim of reducing the seismic vulnerability of these construction typologies. In recent years, many studies have demonstrated the suitability of these materials in enhancing the shear capacity of masonry walls and improve the overall structural behavior, avoiding fragile collapse mechanisms. In the present work, six diagonal compression tests were performed on unstrengthened and FRCM strengthened masonry panels to evaluate the improvements attributable to the presence of the FRCM systems. Two different bidirectional basalt grids were applied to the masonry samples, with and without mechanical anchorages. The tensile and bond properties of the chosen FRCM systems were investigated through laboratory tests. The objective was, indeed, to compare the performances of two textiles, characterized by different densities, and to investigate the role of mechanical anchorages. The experimental results confirmed the efficiency of the FRCM strengthening systems in improving the shear behavior of masonry panels. The FRCM strengthened samples experienced a considerable strength increase and less brittle failure mechanisms. The roles of both the mortar matrix, the fiber grids and the mechanical anchorages were highlighted by analyzing the onset of cracking and the failure propagation within the samples.

Abstract

This paper presents an experimental campaign carried out in an historical industrial building of Barcelona from the 19th century, considering in-situ and laboratory minor destructive testing (MDT) techniques. The results obtained showed a good relationship between the in-situ MDT techniques and the tests carried out in the laboratory. The experimental results from different portions of the large-scale building allowed the discovery of different material typologies deriving from different construction phases.

Abstract

Strengthening with composite materials is becoming more and more an effective solution for increasing the structural safety of masonry buildings, often subjected to severe degradation or potentially vulnerable to seismic events. Structural retrofitting can be performed according to different techniques, based on Fiber Reinforced Polymer (FRP) or Fiber Reinforced Cementitious Matrix (FRCM) strengthening systems. The second group of composite systems is usually preferred nowadays thanks to some important advantages such as better compatibility with the substrate, applicability on wet surfaces, fire resistance, permeability and reversibility. Several experimental and numerical studies can be found in literature concerning masonry panels strengthened with FRP and FRCM systems. The knowledge about the use of the latter, nevertheless, is still partially limited, in particular if the out-of-plane behaviour of walls is taken into account, with the experimental and numerical database available resulting mainly restricted to monotonic cases. In this framework, results of an experimental campaign devoted to the study of the out-of-plane behaviour of tuff and brick masonry walls strengthened with different types of FRCM systems will be presented and discussed in this paper, performing also a comparison with available predictive formulas. Experimental results showed, in general, good performance of FRCM composite materials, with a proper exploitation of their tensile capacity, proving their effectiveness for the out-of-plane strengthening of historical masonry walls.