(1) Associate Professor, University of Minho, Department of Civil Engineering, P-4800-058 Guimaraes, Portugal,

E-mail:; Phone: +351-253-510200; Fax: +351-253-510217

(2) Associate Professor, University Federal of Viçosa, Departament of Civil Engineering – Viçosa – MG – Brazil,

E-mail:; Phone: (+55) 3138991488; Fax: (+55) 3138991481

(3) Associate Professor, University Federal of Minas Gerais, Departament of Structural Engineering – Belo Horizonte – MG – Brazil, E-mail:; Phone: (+55) 3132381986


The design of masonry infill is an issue that has attracted the attention of several researchers in the past, both from the experimental and analytical points of view. Nevertheless, the results are often questionable due to the large variability of masonry properties, the limited number of tests carried out and the large number of influencing factors. This paper addresses this limitation by using numerical analysis as a simulation of an experimental laboratory, and by performing a sensitivity analysis about the influence of the different influence factors. The modelling approach was validated using the experimental results from two masonry walls subjected to horizontal loading and exhibiting diagonal tensile failure and corner crushing. The parametric study subsequently carried out allowed a strut-and-tie model toe proposed that provides a novel simplified expression for the failure of infill walls in frames subjected to horizontal loading. The proposed model is compared with other models available in the literature. It is found to exhibit superior performance and constitutes a simple and versatile tool for design.