Assessment of the in-plane shear capacity of masonry panels by elementary mechanical models

The present paper revisits the classical problem of a masonry panel clamped at its base and subject to an assigned set of in-plane loads at its upper base. The simple model presented herein seems to be able to provide some useful information on various issues involved is assessing such structures. To this end, two simple, straightforward working hypotheses are assumed: the masonry is represented as a rigid-plastic material for which the Galileo-Rankine yield criterion is adopted. By virtue of their simplicity the adopted assumptions enable applying the static and kinematic theorems of limit analysis to obtain explicit expressions for the lower and upper bounds for the horizontal load collapse multiplier. These expressions lead to some considerations regarding the influence of the main geometric and mechanical parameters on the load bearing capacity of the panels. The main theoretical result consists of estimating the range to which the actual value of the ultimate horizontal load belongs as a function of the panel's slenderness and the masonry's strength. Comparisons between the present model's predictions and the experimental test results available in the literature on panels of very different slenderness and material makeup exhibit more than satisfactory agreement.