THE VERTICAL REINFORCEMENT IN THE BOUNDARY ELEMENTS SHOULD BE SUITABLY CONFINED TO IMPROVE THE DUCTILITY OF THE SHEAR WALLS.

SHEAR WALLS :-- Building frames are required to resist gravity loads and lateral loads due to wind or earthquake action . A moment resisting frame tends to be uneconomical beyond 20 stories as it is unable to.control lateral deflections. To Improvement the lateral stiffness and economy ,reinforced concrete shear walls are introduced in buildings exceeding 20 stories in height.These walls may be added solely to resist lateral forces or concrete walls enclosing staircases or elevator shaft may also serve as shear walls. A shear wall can have any plan shape such as linear, angular or circular. Doors , windows and service ducts require that exterior or interior shear walls be provided with openings. A shear wall may contain one or more vertical rows of openings. The wall on each side of the opening may be interconnected by short and the deep beams such walls are referred to as coupled shear walls. The coupling beams transmit shear forces from one wall to another, because of the small span to depth ratio,shear deformation may become significant in these beams .The behaviour of the shear walls is influenced by their proportions as well as the support conditions.Thus shear walls of low height to depth ratios may be expected to fail in shear .High shear walls are controlled by flexure requirement rather than by shear and behave like a vertical cantilever beam .The latter may be designed as any regular flexural element .The term shear wall is a misnomer. It indicates that such elements resist  major portion of the lateral shear in buildings through flexural deformations and does not suggest the failure mode of such element .The lateral forces act on the edges of each floor or roof .The horizontal floors act as deep beens to transmit loads to vertical wall elements.These walls act as vertical cantilever beams fixed at their base to carry loads down to the foundation.