STUDY OF FAILURE AND DEFORMATION CHARACTERISTICSOF SHEAR WALL WITH OPENINGS USING CONCEALED STIFFENERS

Shear wall is a structural member provided in multistoried structure for resisting wind and seismic forces acting in the horizontal direction along the plane of the wall. Openings are provided in shear wall generally for meeting a functional requirement or for providing building services like ducts for electric wiring. Strength of any structure reduces due to provision of opening and it is equally true for shear wall also. Long walls fail generally by flexure whereas short wall fails by shear. In case of long walls, failure is generally observed in the critical region which is at 1/6th height of the wall on the either sides. However, short walls fail at the bottom due to the crushing of concrete or yielding of reinforcement. Failure along diagonal is also observed in some cases. If openings are provided in a shear wall, failure is observed at corners or along edges of the shear wall. This type of failure is due to the stress concentration around the opening. Strength of shear wall also decreases due to a reduction in concrete area and discontinuity of reinforcement due to opening. Formation of cracks in the early stage of loading leads to failure of shear walls. To avoid this problem of early failure some provisions have to be made to improve the behavior of shear wall with an opening. To overcome this problem it is proposed to providing concealed diagonal stiffeners in shear wall along diagonal and periphery of opening. In the present study, six shear wall models with the central opening are tested to know the effect of concealed stiffeners in the shear wall with an opening. A significant improvement was observed in the behaviour of the shear wall with opening using concealed stiffeners. The main focus of this study is to know the deformation capacity, crack pattern, failure mode and strain character.