Evaluation of Compressive Strength of Masonry Walls by Limit Analysis

Abstract

The bearing capacity of a masonry element subjected to compression is generally determined by elastic calculations that take into account the different mechanical properties of the constituents. Compared to experimental checks, these estimates show a systematic error in the order of 50‐100%. This is due to the impossibility of defining unequivocally the values of the normal modulus of elasticity and of the transversal contraction coefficient (especially for mortar). These observations suggest that the problem should be approached from a totally different point of view, i.e., not confining the stress analysis to the elastic phase, but taking into account the inelastic phase preceding the rupture. In this work, an evaluation of the bearing capacity is carried out by superimposing a field of fundamental stresses that is balanced with the assigned compressive load, and plane fields that are balanced with null forces. This technique provides only the lower limit of the collapse load. The model reproduces closely the qualitative features of the rupture behavior of masonry described by experimental results available in the literature.