Stability analysis of clay brick masonry columns: numerical aspects and modelling strategies

Stability analysis of masonry piers and columns is one of the most frequently treated subjects in the field of structural engineering. This attention is probably due to the challenge to solving the problem including different effects, which play an important role in evaluating the response of eccentrically-loaded columns. In this connection, accurate stability analysis of masonry piers and columns has to take into account the non-linear stress–strain law of masonry in compression, the limited tensile strength, the induced slenderness due to crack formation and geometrical non-linearity. Different theoretical models and numerical approaches were developed in the past to analyze the combined effect of buckling and strength in such structural members. In this paper a numerical method is derived and particularized for the case of clay brick masonry members. After a review of the most widely used analytical models for the compressive behaviour of masonry, the effects of a non-linear constitutive law in compression and cracking were taken into account with suitable moment–curvature curves. The latter were implemented in a simple numerical procedure, and made it possible to calculate the force–displacement curves and safety domains, which account for both strength and stability. The method was finally verified with results derived from non-linear finite element analyses, making it possible to make considerations about the suitability of the method and the related computational effort.