Lateral response of damaged stand-alone arches: Tilting tests and rigid-block analysis

•The presence of localized defects strongly affects the structural response of curved structures.•Horizontal settlements can lead to a better structural behavior of curved structures.•Tilt testing is a suitable tool for assessing the capacity of stand-alone no-tension resistant arches.•Rigid-block analyses can be effectively adopted to reproduce the experimental evidence. Arches are a structural solution widely adopted in the past, especially when masonry was the most used constructional material. Their wide-spreading can be, indeed, found in both infrastructural and monumental constructions, as well as ordinary historical buildings. From the mechanical point of view, due to their geometrical configuration, arches mainly experience compressive stresses under external loads. Thus, given also the close-to-zero tensile strength of the masonry, it is a common practice in engineering applications to consider arches as no-tension resistant element. On the other hand, due to the ancientness of masonry structures, arched structures can often experience structural defects, such as the local reduction of the thickness and the occurrence of toward-outside support movements. In this paper, the seismic response of stand-alone arches affected by these defect typologies is investigated by means of experimental tests and rigid-block analysis. In particular, 196 tilting tests on different geometrical configurations of small-scale arches affected by local reduction of the thickness and horizontal movement at one support are performed. The results of the experimental campaign generally showed that the localized defect can strongly influence the lateral capacity of the arches. Conversely, the simultaneous presence of horizontal support movement and local thickness reduction, in some cases, can return a quite different response with respect to the cases with the sole thickness reduction. Then, the obtained results are numerically interpreted by means of an automatic procedure implemented in MATLAB®, which allows for assessing the failure conditions of the performed tests by resorting to the limit analysis concepts. On the whole, a very good consistency between the experimental and numerical evidence is obtained.