Effect of Masonry Infill Wall Configuration and Modelling Approach on the Behaviour of RC Frame Structures

Abstract

The masonry infill walls influence substantially the response of reinforced concrete (RC) buildings under lateral loading due to their contribution to strength and stiffness. In the literature, there are several approaches for modelling the infill walls. However, they provide different results. In this study, the equivalent diagonal strut model was used. The basic parameter of this strut is its equivalent width. In the first stage of the study, various equations available in the literature for determining the width of the compressed diagonal strut were compared. Among them, Paulay and Priestley relation which gives approximately average value was selected for modelling the masonry infill walls. In the second stage of the study, a sensitivity analysis was performed by considering 2-, 4-, 6- and 8-storey RC bare frames and those with infill walls. Four different infill wall frame configurations, namely fully infilled frame, fully infilled-except first storey frame, interior bay infilled frame and interior bay infilled-except first storey frame, were adopted. Single-strut and three-strut models for simulating wall panels were used in all infilled frames. Thus, a total of 36 different RC frame models were evaluated through the nonlinear pushover analysis in order to appraise the infill wall effect on the overall response of the case study frame buildings. The analysis of the results indicated that the arrangement of the infill panels over the elevation of the frame remarkably influenced the performance of structures. Moreover, the serious capacity degradation was observed especially for the case of infills discontinued at the ground level.