Studying the Effect of Masonry Infill Walls on The Natural Period and Lateral Behavior of RC Buildings in Comparison with the SBC [ ]


Although the reinforced concrete frame-infill systems are used throughout the world, they are rarely included in the calculations of the natural period or the numerical analysis of the structures. Masonry infill (MI) walls confined by reinforced concrete (RC) frames play a crucial role, either positive or negative, in altering the lateral capacity of buildings they are applied to. This research paper carries dual targets, the first is studying the effect of the infill walls on the natural period of RC buildings with MI walls. Several configurations of infill walls are studied (considering the wall openings). The interaction between the masonry infill walls and the R.C shear walls in buildings is invistigated. Also, this study is intended with investigating the parameters of the equations presented by the Saudi Building Code (SBC) versus other codes to calculate the natural period of shear wall buildings. The second target of this paper is carrying out a nonlinear numerical investigation on the lateral behavior of RC buildings with MI walls. Different configurations of MI walls, size of wall openings, absence of MI walls in the first storey are investigated. The application buildings are either moment resisting frames (MRF) or dual shear wall-moment resisting frames (SW-MRF) buildings. Equivalent strut methodology is used and modified to model the behavior of infill walls taking into consideration the effect of opening sizes. Nonlinear static push-over analysis is carried out for the applied case study buildings.