Analytical estimation of lateral resistance of low-shear strength masonry infilled reinforced concrete frames with openings

Presence of openings in an infill wall alters its behavior and reduces load resistance and stiffness of the infilled frame. In this paper, a simple method for estimating the lateral resistance of infilled frames with openings is proposed based on experimental data. Six half-scale, single-story single-bay reinforced concrete frame specimens were tested under in-plane lateral loading. The lateral strength of reinforced concrete (RC) frame could be estimated by assuming the formation of plastic hinges in the end regions of the members. In the specimens with central openings, the major load resistance mechanism of the infill panel was the formation of a compression strut and lateral strength of infill panel could be considered as the smallest values of the diagonal tension and corner crushing modes. In the specimens with eccentric openings, the load resistance mechanism of masonry infill was the formation of a compression strut and bed-joint sliding in 2 opposite loading directions; thus, the lateral resistance of infill panel could be estimated in diagonal tension and corner crushing modes in one direction and bed-joint sliding mode in another direction. Furthermore, the deformation capacity and structural performance levels are suggested for solid and perforated infill panels based on test observations.