Experimental and Numerical Analysis on the Effect of Joint Deformability and Imperfections on the Response of Masonry Arches Subject to Large Support Displacements

Large support displacements are a major threat for masonry arches. In the last decades, the stability of masonry arches under large support displacements has been often analysed through analytical and numerical methods that adopted Heyman’s assumptions on the behavior of masonry arches and modelled arches as rigid-no tension structures. Although these methods were generally able to capture the collapse mechanisms observed in the experimental tests, they overestimated, even significantly, the experimental displacement capacity. The main aims of this paper are to investigate the reasons why rigid-no tension models fail in accurately predicting the actual response of dry-joint masonry arches to large support displacements and to propose a numerical modelling approach able to obtain a better matching between experimental and numerical responses. To achieve these goals, the case of a small-scale segmental dry-joint masonry arch tested to collapse under vertical, horizontal, and inclined support displacements was investigated. To simulate the experimental tests, a finite element micro-modelling approach was adopted. The arch was schematized as an assemblage of elastic and stiff voussoirs interacting at no-tension friction interfaces, which were considered alternatively rigid or deformable. The comparison between the numerical and experimental results demonstrated that the discrepancies between the predictions by rigid no-tension models and the experimental outcomes were due to the imperfections and resulting deformability of the joints of the physical model. A strategy to account for this deformability in the adopted modelling approach was thus proposed and validated by comparison with the experimental results.