Experimental testing of the seismic in-plane displacement capacity of masonry cross vaults through a scale model

Abstract

Since cross masonry vaults represent one of the more widespread types of horizontal structural elements in historical constructions, understanding their behaviour is a crucial precondition for the accurate assessment of the global response of buildings to earthquakes. In spite of the importance of this topic, the complexity of evaluation three-dimensional response of vaults still represents a challenge for researchers. Experimental investigations can be a valid tool to analyse this difficult problem, as they provide useful results that can validate the reliability of the numerical and analytical tools developed for analysis. In this paper, the results of an experimental campaign on 1:5 scale model of a masonry cross vault are presented. The main aim was to evaluate the response of the vaults in the context of a global analysis of historic masonry buildings by determining their ultimate in-plane seismic capacity (diaphragm effect) in terms of stiffness, strength, and ultimate displacements. Their three-dimensional damage mechanisms on the vaults was also described. The model, made of 3D printed plastic blocks with dry joints, was tested by statically applying different horizontal displacements settings to the abutments in order to simulate differential displacements of the supports (walls or pillars). In particular, in-plane horizontal shear distortions and longitudinal opening/closing of the abutments, as they are the most common seismic damage mechanisms seen in masonry vault buildings, were applied.