Dynamics of masonry pointed arches under base motion

The paper deals with the topic of the seismic assessment of masonry pointed arches, one of the typical resistant systems of unreinforced masonry structures, whose vulnerability has been further highlighted by damages and collapses occurred with recent seismic events. According to the hypotheses of limit analysis and following the Oppenheim's approach, a single-degree-of-freedom analytical model is proposed to study their dynamic behaviour. The structure is represented as an assembly of rigid bodies, connected through hinges with each other and subjected to a horizontal ground acceleration. An ad hoc energy dissipation model is specifically implemented for the studied case, according to the classical Housner's approach. A comparison with the circular arch case is shown with reference to the arch geometry studied by Oppenheim, tracing the main features and differences. Finally, a numerical survey is carried out by varying the main geometrical parameters of the pointed arch, in order to evaluate their influence on the dynamic response.