Lateral load response of semi-interlocking mortarless masonry-infilled frames

Structural frames infilled with masonry material called masonry-infilled frames (MIFs) are common types of constructions around the world. These structures generally have mortared masonry as infill material which made the buildings stiff during past earthquakes and generated additional torsional forces. With a view to improve the seismic performance of MIFs this paper presents the results of a numerical simulation study on the behaviour of previously-tested MIFs with semi-interlocking masonry (SIM) material. In a simplified micro-modelling approach, the concrete and masonry materials are simulated using Concrete Damaged Plasticity technique and the joints are considered as zero-thickness cohesive interfaces modelled using traction-separation model. The numerical model is then used to study the lateral load response of the alternate MIF with SIM. The methodology for FE modelling of MIFs with SIM as an infill material is developed and explained in detail. The numerical models incorporate the sliding of the masonry units under the application of lateral loads. It is shown that the models capture the experimental results quite well although the modelling technique has certain limitations. The outcomes of a sensitivity analysis on the effects of the interface mechanical properties are presented along with discussion of limitations and suggestions for future improvements.