Stability of Masonry Walls Subjected to Seismic Transverse Forces

The stability condition of masonry walls subjected to seismic transverse forces is investigated by translating the problem into the analysis of a fixed–free ended prismatic column undergoing static horizontal forces equivalent to the maximum inertia actions. The column is assumed to be made of a no-tension material, with a linear stress-strain law in compression. The solution is achieved by a numerical model in which the column is ideally divided into a sufficiently high number of elements, each with uniform curvature. With reference to the deformed shape corresponding to a given load condition, this approach allows the stress and strain characteristic quantities of a cross section to be expressed recursively, and the stability domain to be defined in dimensionless terms. In the general case of a column subjected to its own weight, to a concentrated eccentric compressive load acting at the top, and to the related horizontal inertia forces, the results show that large-displacement effects, due to the material flexibility, can considerably reduce the maximum slenderness value corresponding to the rigid-body equilibrium condition.