Architectural Construction Department, Polytechnic University of Madrid, Spain

In the absence of field data, an experimental test programme was conducted at the INTEMAC Central Laboratory to determine whether the deformability of Medieval masonry varies with joint mortar thickness in the range found in Spanish Gothic cathedral structural members.
A compression test was designed to determine the effect of joint thickness on sample performance and an axial loading test was conducted at different angles to simulate the thrust of the resultant on the vault.The results showed that joint mortar thickness has a substantial impact on stone masonry deformability.Analytical models should, therefore, include information on this parameter if they are to provide a more rigorous understanding of structural behaviour.