Analytical and parametric study on masonry infilled reinforced concrete frames using finite element method

A nonlinear finite element method model for masonry infilled reinforced concrete frames was used to conduct a parametric study on the effects of reinforced concrete frame—masonry infill interface stiffness, aspect ratio of infill panels, pre-compression of frame, and the effect of different opening locations on performance of such frames. The used finite element method model was capable of detecting interface failure/separation between frame and infill besides computing forces and displacements in the frame and the masonry infill. Experimentally determined masonry infill panel material properties as well as interface stiffness values for different types of masonry infill blocks, interface locations, and field practices were used in the finite element method model. It was found that an increase in interface stiffness around all sides of the infilled frame was required for any positive impact on frame performance. Increasing the aspect ratio resulted in an increase in stiffness of infilled frame. However, increasing the pre-compression load did not affect frame lateral displacement for lateral load up to 40 kN. Afterward, it showed a decrease in 8%–37% for various levels of pre-compression. Openings in the infill reduced the infilled frame stiffness only when these were located in the path of the diagonal compression strut.