1 Doctoral Student, Department of Civil Engineering, Indian Institute of Technology Kanpur, Kanpur, India, singhal@iitk.ac.in
2 Professor, Department of Civil Engineering, Indian Institute of Technology Kanpur, Kanpur, India, dcrai@iitk.ac.in
ABSTRACT
Load-carrying capacity of masonry walls in the in-plane and out-of-plane directions is affected by presence of openings and type of interface present at the wall edge and the column face. Six half-scaled clay brick masonry wall panels were subjected to a sequence of slow cyclic in-plane drifts and shake table-generated out-of-plane ground motions. Two specimens were regular masonry RC infilled frame with and without window openings. In the other four specimens, confining frame elements were constructed after the masonry wall with one solid wall while the other three had perforations for door and windows bounded by RC confining grid elements on all sides.
Specimens with infill panel demonstrated higher risk of out-of-plane collapse whereas confined masonry wall specimens maintained structural integrity and out-of-plane stability even when severely damaged. The significant improvement in the in-plane lateral load resistance was observed for masonry walls with window openings confined on all four sides; about 70% higher in-plane capacity was observed as compared to regular infill panel with opening. Specimens with appropriate confinement around the openings are able to compensate for the presence of opening and can achieve the performance of the solid masonry wall. Moreover, constructing the masonry wall first and RC elements later, considerably enhance the interaction between masonry walls and frame, which helped delay the failure by controlling out-of-plane deflections even after in-plane drift cycle of 2.1%.
KEYWORDS: confined masonry; seismic behavior; in-plane and out-of-plane loads
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