Masonry structures are often encountered in the historical architectural heritage being used from Chinese, Babylonians, Egyptians, Greeks, Romans and many others until modern times. Though many of these architectural marvels have survived for centuries keeping their historical, cultural and economical values: due to material degradation, imposed displacements, structural alterations or increased service loads, some members may need repair and/or strengthening. For this purpose, fiber-reinforced polymer (FRP) composites in the form of bonded laminates applied to the external surface with the wet lay-up technique are an effective solution. In addition to being structurally effective, FRPs present several advantages over conventional techniques: they add no extra weight to the structure, are corrosion-resistant, have minimal aesthetic impact, and can be easily removed. In particular, the adhesion mechanism between masonry and FRP was investigated by few researchers in the last years although it is a key issue when dealing with the strengthening of masonry constructions. In this paper an approach based on the incremental theory of multi-surface plasticity able to assess the influence of several parameters on the FRP-masonry interfacial behaviour is presented and the main results of a numerical analysis of bond between FRP strips and brick masonry in bond tests are provided. The mechanical characterization of the basic materials and of the local interfacial behaviour allowed defining the main parameters and the constitutive law to be adopted. Based on experimental results, a detailed finite element (FE) micro-model has been developed, which enables to describe the adhesion phenomenon at local level up to the ultimate load, identifying the strain and slip distribution, the local bond stress peak and its migration along the bond-length. Moreover, to validate the numerical results, an analytical study is achieved allowing a deep insight of the FRP-masonry interfacial behaviour.
Keywords: Adhesion; FRP; Masonry; Historical Heritage;
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