Marina Damiola1, Rita Esposito2, Francesco Messali3, and Jan G.Rots4
Delft University of Technology, Faculty of Civil Engineering and Geosciences
Delft, The Netherlands
{M.Damiola1, R.Esposito2, F.Messali3, J.G.Rots4}

Keywords: Unreinforced masonry, Two-way out-of-plane failure mechanism, Virtual work method, Quasi-static cyclic tests

Abstract. Out-of-plane failure is one of the most important mechanisms for unreinforced masonry (URM) structures to be prevented in the seismic areas. The one-way out-of-plane bending failure mechanism has been studied by several authors. The two-way bending failure mechanism has received much less attention and only few formulations for specific cases are available in standards and in the literature.
In order to investigate the two-way bending failure mechanism, four full-scale URM walls were tested quasi-statically. Both calcium silicate and clay brick masonry typical of Dutch building were tested. In comparison with the experimental results, a critical evaluation of the available analytical models proposed by Eurocode 6, the Australian standards and the simplified macroblock approach by Vaculik and Griffith is presented. Despite some limitation in its application and the underestimation in the results, the most promising analytical formulation is the one provided by the Australian standards. In order to provide a basis for the development of an improved formulation for two-way bending, a parametric study on the Australian standard formulation is presented. The parameters that mostly influence the prediction of the bending capacity of the wall are the flexural strength of masonry, the vertical edges rotational restrain coefficient, the aspect ratio, and the wall thickness. On the contrary, the parametric study also shows that variations of the overburden do not lead to variation in terms of capacity.