Evaluation of different computational modelling strategies for the analysis of low strength masonry structures

• Historical masonry structures are usually characterized by low strength, difficult to model.
• Low bond strength masonries have been modelled using FEM and DEM.
• In low bond strength masonry emphasis is on joint behaviour, DEM performs better.
• In low unit strength masonry, emphasis is on the brick: FEM is more reliable.
• Neither the FEM nor the DEM approach could be considered “reliable in every case”.

Masonry is a composite material characterized by a large variability of its constituent materials. The materials used, the quality of the bond and variations in the standard of workmanship significantly affect the mechanical performance of the overall masonry structure. Masonry structures, especially the historical ones, are usually characterized by low strength, due to a variety of reasons, namely low units and/or mortar strength or low bond; this makes more difficult to study these types of structures according to general rules because of different structural schemes. The aim of this paper is to evaluate the suitability of continuous FEM (Finite Element Method) or discrete DEM (Distinct Element Method) approaches to analyse the behaviour of low strength masonry and to contribute to the knowledge and selection of the best approach with a cost and time effective solution. The comparison with experimental results on different low strength masonry validated the approaches and showed that, for low bond strength masonry, DEM approaches performed better compared to low unit strength masonry where the emphasis on joint behaviour in DEM approaches is less effective because the weak component is the unit.