The role of shape irregularities on the lateral loads bearing capacity of circular masonry arches

Abstract

The paper is aimed at assessing the shape irregularities effect on the collapse conditions of circular masonry arches in presence of horizontal actions. Historical constructions often present structural elements characterized by irregular shapes, which could affect their bearing capacity if calculated considering the nominal geometry. Some of these irregularities can be ascribed to the arising of deformed states developed over time or, in other cases, directly to technological construction processes. As a first study, the geometrical uncertainties related to construction processes are considered. In order to take into account such irregularities type, a random model of a polycentric arch has been developed. A Monte Carlo simulation approach allowed to estimate the probability density function of the horizontal collapse load multiplier obtained through a limit analysis procedure. The comparison between the results obtained for the masonry arch with nominal geometry and those obtained with the random geometrical irregularities highlighted the effects of that shape uncertainties on the carrying capacity of this type of structures.