Evaluation of Seismic Behavior of RC Moment Resisting Frame with Masonry Infill Walls

Masonry infill walls are frequently used as interior partitions or exterior walls for low-rise RC buildings. These infill walls are usually considered to be non-structural elements, and thus they are ignored in analytical models, because they are assumed to be beneficial to the structural behavior. In order to test this hypothesis, structural analyses were performed for a low-rise RC moment-resisting frame with and without masonry infill walls. From the analytical results, it has been shown that masonry infill walls can increase the strength and stiffness of a building structure, resulting in a decreased inter-story drift ratio. However, seismic forces applied to the structure are increased, because natural periods of the structure are shortened by the increase of stiffness. It should be noted that partial damage of infill walls between floor slabs can cause vertical irregularity of the strength and stiffness of the structure. It has also been shown that the inelastic deformation of a RC moment-resisting frame with a soft story is concentrated on the first story columns, and this partial damage may cause collapse of the entire system. To solve this problem, a structural design method has been proposed in this study.