Development of a three-dimensional computational model for the in-plane and out-of-plane analysis of masonry-infilled reinforced concrete frames

Structural frames, constructed either by steel or reinforced concrete (RC), are often infilled with masonry panels. In design, they are usually treated as non-structural elements, and their interaction with the bounding frame is often ignored. However, recent studies have demonstrated that infilled frame can be superior to a bare frame in terms of stiffness, strength and energy dissipation, when the structure is subjected to strong lateral loads including earthquakes. Today, several models have been developed to evaluate infilled structures. Nevertheless, such models have been validated with limited experimental data, and they have demonstrated different performances when compared with test results. This paper presents the development of a three-dimensional computational model based on the finite element method (FEM) that has been used to study the in-plane and out-of-plane behaviour of masonry infilled RC frames containing openings. Masonry infill walls were modelled as an assemblage of stiff yet deformable bricks while mortar joints as zero thickness interfaces. Initially, the material and interface parameters were determined by carrying out a series of small scale tests. The computational model was then used to predict the in-plane and out-of-plane behaviour of a series of full scale infill wall panels constructed in the laboratory using a similar brick and mortar combination. From the results analysis, it was shown that the FE model was capable of capturing the mode of failure and the load carrying capacity of the masonry-infilled RC frame with sufficient accuracy.