Contribution of RC columns and masonry wall to the shear resistance of masonry infilled RC frames containing different in size window and door openings

In design, the contribution of the masonry infill wall to the shear resistance of the infilled frame structural system is often neglected. However, past research shows that ignoring this element can lead to inaccurate predictions of the system’s behaviour. This paper investigates the influence of the opening type, size and position on the shear resistance and deformation capacity of individual components (infill and frame) in masonry infilled reinforced concrete (RC) frame structures. A computational model based on the non-linear finite element (FE) method of analysis has been developed. The computational model has been validated against a series of experimental tests carried out in the laboratory. An extensive parametric study was carried out and the influence of differences in size and location of window and door openings on the shear resistance of infilled frame was investigated. As a measure of the influence of the infill component, a shear resistance ratio for the frame was introduced. The normalized shear resistance capacity ratio represented the ratio of the shear force taken by the frame component (infilled frame case) divided by the shear force induced by the RC bare frame at observed drift ratios (damage grades). From the results analysis, it was found that the type of opening influences the design characteristics of the infilled RC frame. In particular, the shear resistance at columns of the infilled RC frame with a window opening is lower than the shear resistance of the columns of the RC frame. In contrast, the shear resistance at the columns of the infilled RC frame with a door opening is higher than the shear resistance of the columns of the RC frame, and in this case the contribution of the shear capacity of the frame is underestimated.