Investigation of torsion in confined masonry structures originating due to unsymmetric openings

A detailed comparative study was carried out to investigate the impact of unsymmetric openings on the torsional resistance of confined masonry rooms constructed in highly seismic-prone regions. To investigate in detail, an experimental and numerical investigation was carried out. Confined masonry wall panels with and without openings were experimentally tested to study the reduction in stiffness/lateral load-carrying capacity of walls due to the provision of openings. Further, a three-dimensional masonry room was tested experimentally to determine the torsion induced due to openings in confined masonry rooms. It was observed that on the provision of unsymmetric openings in confined masonry rooms, torsion was observed causing a reduction in the load-carrying capacity. The same was also confirmed using numerical simulation where it was revealed that on the provision of unsymmetric openings, 10% reduction in lateral load carrying capacity was observed in the confined masonry rooms as compared to the room with symmetric openings. Similarly, a lesser difference (0.1 mm) in the displacements between two corners of the wall opposite to the applied load was observed in the case of the confined masonry room having symmetrical openings on opposite sides. Therefore, it might be concluded that in highly seismic-prone regions, the provision of symmetric openings or utilizing other means of manipulating in-plane wall stiffness should be considered to reduce the impact of torsion.