Failure modes prediction of masonry voussoir arches on moving supports

This paper reports numerical and experimental investigations carried out to analyse vulnerability of masonry voussoir arches when subjected to soil settlement. A novel numerical procedure aimed at predicting collapse layout and limit settlement is here presented. To identify the location of the three hinges that open when the settlement triggers, a procedure based on combinatorial analysis is exploited together with both static and kinematic analysis. In the framework of finite displacements, the limit settlement of an arch is also found checking equilibrium at every step increase of the settlement. Good agreement is found between experiment results provided by reduced scale arch models, made of blocks of PVC and subjected to a horizontal or vertical settlement of the left support, and numerical predictions. Furthermore, a sensitivity analysis has been carried out in order to assess the trend of the limit settlement in relation with ring thickness and number of blocks. Results show that the limit settlement for spreading supports is independent from the number of blocks for a given angle of embrace.