International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056 Volume: 04 Issue: 07 | July -2017
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p-ISSN: 2395-0072
Seismic Analysis of RC Shear Wall Frame Buildings with and Without Openings in Shear Wall Syed Mohammad Umar1, Rizwanullah2 1M-Tech (Structure and Foundation Engineering), 2 Assistant Professor Department of Civil Engineering, Al-Falah University, Faridabad, INDIA ---------------------------------------------------------------------***--------------------------------------------------------------------3. STIFFNESS/RIGIDITY OF SHEAR WALL Abstract - The paper investigates the effects of openings
in shear wall on seismic response of structures. For parametric study 15 storied 4mx5m bays apartment buildings with typical floor plan of 25mx12m and floor height of 3m with different openings size and location in shear walls were modeled in ETABS-2015. An equivalent dynamic analysis for three dimensional models of the buildings was performed as per IS 1893 (part 1): 2002. Seismic responses of the analyzed structures were compared. The results reveal that for opening area < 15%, the stiffness of the system is more affected by the size of openings than its arrangement. However, for opening area >15%, the stiffness of the system is significantly affected by openings configuration in shear walls.
The stiffness/rigidity of a shear wall in a given direction (Rx or Ry) is defined as a force required per unit displacement in the given direction. Varyani (2002) states that the deflection (Δx) of a wall element regarded as a deep cantilever beam fixed at base due to a shear Vx applied in x direction at a height h′ from top is composed of deflection due to bending and shear (Figure 1). The deflection (Δx) is given; (01) Where, E = modulus of elasticity of material of shear wall G = E/2(1+ν) = shear modulus of material of shear wall I = moment of inertia of shear wall about the axis of bending A = area of web about the axis of bending Δ = deflection due to applied shear in a given direction h = height of shear wall element h′ = height of applied shear above the top of wall element
Key Words: Openings, Shear wall, Stiffness, Seismic response, Rigidity, Modifier
1. INTRODUCTION Shear walls are introduced in modern tall buildings to make the structural system more efficient in resisting the horizontal loads that arises from wind and earthquake. The introduction of shear wall represents structurally efficient solution to stiffen a building structural system. The main function of shear wall is to increase the rigidity of lateral load resistance.
Assuming Poisson’s ratio ‘ν’ = 0.17 and V acts at the top of shear wall making h′ = 0, the rigidity of the wall element in x direction is given by: (02)
2. OBJECTIVE OF THE STUDY Shear walls in apartment buildings may have rows of openings that are required for windows in external walls or for doors ways or corridors in internal walls. The size and location of openings may vary from architectural and functional point of view. It may have adverse effect on stiffness of shear wall as well as on the seismic response of frame-shear-wall structures. Relative stiffness of shear walls is important since lateral forces are distributed to individual shear wall according to their relative stiffness. Thus, the main objective of this study is to study the effects of openings & its configurations in shear wall on seismic response of the buildings.
Similarly, the rigidity of the wall element in y direction is given by: (03)
3.1. Solid rectangular shear wall For solid rectangular shear wall with t << L (04) (05)
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