Finite-element analysis of out-of-plane behaviour of masonry infill walls

Masonry infill walls should have sufficient out-of-plane stability to ensure the safety of people and the performance of safety-relevant components. The behaviour of masonry infill walls under out-of-plane loading, which is caused by earthquakes due to the mass and inertia of the wall, is crucial to the overall safety of buildings. A simplified micro non-linear three-dimensional finite-element method for simulating the behaviour of masonry infills under out-of-plane loading is presented in this paper. Appropriate experimental data from the literature are utilised to examine the capability of the model. A parametric study is presented using the connection conditions of the wall and frame, the slenderness ratio, the compressive strength of the masonry and the aspect ratio as parameters. It is shown that the model can simulate the various crack patterns observed in experimental studies reported in the literature. Based on the results of the parametric study, a simplified formula is developed to compute the out-of-plane load resistance of a masonry infill wall. A comparison of the results from the simplified formula and experimental data indicates that the formula can be employed to predict the out-of-plane strength of masonry infill walls in reinforced concrete frames with acceptable accuracy, except for those with extremely small slenderness ratios.