Comparative Study of Linear Static Analysis of G+10 Storey Building with and Without Shear Wall in ETABS

Planning, designing, and execution of high-raise building while taking into account the impact of lateral loads such as wind and seismic loads computation with or without shear wall technology in conventional mode is a crucial task for civil engineers. The lateral loads develop high lateral stresses and sway movement in structural members and need adequate stiffness to resist lateral forces along with sufficient strength against vertical gravity loads. In this case, civil engineers establish an effective system for construction of high raise building with the usage of shear wall system is high in-plane stiffness and torsional resistance. Present the authors are considered a G+10 storey commercial shopping mall with a central cut-out at Bhimavaram location which lies in seismic zone III as, per IS 1893(part 1): 2016. The load cases from IS 875 Part I (dead loads), Part II (imposed loads), and Part III (wind loads) are used to create the load combinations in accordance with IS 456: 2000. Two models, with and without shear wall system are taken for comparing the parameters like storey drift, storey displacement, stiffness, shear force, base shear, bending moment and center of rigidity by performing linear static seismic analysis and wind analysis for both models in ETABS software. The simulations concluded that Shear wall system is the efficient and economical way of resisting lateral loads in high rise or multistory buildings.


Introduction:
In recent years, civil engineers have been under pressure to build high-rise buildings due to land scarcity, increased land costs in several cities and towns, and to facilitate the increased population of megacities.The construction of high-rise buildings for residential, commercial, and celluloid uses and among others in an area must be designed efficiently to ensure people's safety.The Civil engineers planning and design of high-rise building structures need to consider which are impacted by lateral loads like wind and earthquakes.In designing high-rise buildings, civil engineers consider the seismic load component, which is a fundamental concept load in earthquake engineering.Seismic load occurs sudden movement or disturbance in the earth due to sudden break in underground rockand motion in along the fault, which releases lot of energy rapidly.The unpredictable releases of energy damages any building structures.As a civil engineer, while designing the building structure, it is to be withstanding the lateral forces to be achieved through stiffness improvement.One good wayto resist these loads is by adopting a shear wall system in a building.Shear wall is a structural component in a building with high in-plane stiffness and transfers the wind and earthquake loads tothe foundation more efficiently than a typical reinforced-concrete (RC) framed building.
Structural engineers must aim for the most precise, effective, and affordable design possible in order to guarantee that the structure's final design and the building itself must be functional for their anticipated to use lifetime on the basis of it designed.For designing and analysis of building structures several software's are available at globally such as ETABS, MIDAS, RISA, RAM, SAP, STAADPRO, STRUDL.However, the current work utilises ETABS software to explore linear static analysis of a multi-story (G+10) building with and without shear walls.To achieve the frame work the following objectives are framed for the study area.

OBJECTIVES •
To Investigate about Shear force, Bending Moment, Story drifts, story displacement, Storystiffness, story shear, centers of mass rigidity of buildings with and without shear walls.[/] = i i ƒƒii ƒ iƒƒ i .
Force Distribution in the Design Base Shear Vertical Distribution to various Floor Levels.
The following guidelines must be followed while distributing the design base force (VB) along the building's height: 2 VB  Design lateral force at the floor is Qi. Hi is the height of the floor measured from the base, where Wi is the seismic weight of the floor. The number of levels where the masses are situated is determined by the number of stories in the building, or n.

Center of Mass And Center of Rigidity
The centre of mass, also known as the centre of rigidity, is where the entire storey's mass acts, whereas the centre of stiffness, also known as the centre of rigidity, is where the entire stiffness acts.Vertical resisting systems like columns and shear walls-the latter being stiffer-contribute significantly to the stiffness.However, beams also add to mass.The eccentricity, or distance between the centres of mass and rigidity, must be at a minimum for a structure to be resistant to a torsional moment.The comparative plot between the centre of mass and the centre of rigidity in both the X and Y directions with and without shear wall situations is shown in Figure 5 and was derived using ETABS after analysis.

Story Stiffness
The ratio of storey shear to storey drift is known as storey stiffness.The comparative storey stiffness plot for structures with and without shear walls in the X and Y directions is shown in Figure 6.

Story Displacement
The displacement of a storey with regard to the ground is known as storey displacement.The comparison plot of storey displacement for structures with and without shear walls for EQ-X and EQ-Y loadings is shown in Figure 7.

Bending Moment And Shear Force of Beams And Columns
As there are large number of beams and columns, we have considered beam series '108' and column series '42', which are nearer to perimeter, for comparison.

CONCLUSIONS:
The study is revealed that the models have been safe against all external loads like lateral loads and internal loads like live loads, dead loads and superimposed dead loads according to IS 875 (parts I & II) for commercial shopping complex.The positioning of shear wall symmetrically in the building has brought considerable change in parameters like bending moment, shear force, storey displacements, drifts, center of mass, rigidity, storey shear, and storey stiffness.When compared to buildings without shear walls, the bending moment for beams and columns is reduced by up to 43%, while the shear force is reduced by up to 23.56 to 45.8%.Maximum storey displacement for building without shear wall was observed as 175 mm for earthquake load in Y direction which got reduced to 25mm when shear wall system is adopted which is about 85% reduction of storey displacement.Storey drifts for building with shear wall has been reduced by 86.9% as compared to that of building with shear wall.For earthquakes and with wind loads in both X and Y directions, storey drifts were more frequently seen in the second and third stories.The experiment shows that using the Shear Well method in a building as opposed to one without a Shear Wall greatly increases the storey stiffness.

•
To safeguard the structure against all loading conditions • To analyze seismic and wind loads using code of part 11893:2016 and IS 875:2015 (Part III).

FIGURE 3 .
FIGURE 3. Comparative plot of center of mass and center of rigidity for buildings with and without shear walls in X and Y directions

FIGURE 4 .
FIGURE 4. Comparative plot of Storey stiffness for buildings with and without shear walls in X and Y directions

FIGURE 5 .
FIGURE 5. Comparative graph of storey displacement for buildings with and without shear wall for EQ-X and EQ-Y loadings Storey Drift

FIGURE 6 .
FIGURE 6. Comparative plot of Storey drifts for building with and without shear wall for (a) WX and WY loads (b) EQ-X and EQ-Y loads

Figure 9
is the elevation view of frame 5-A-B-C-D-E-F-G-H-I-J-K-L-M-N-O-P.The results of bending moment and shear force for load combination, (1.2 D.L+1.2 L.L+1.2 EQ-X) are considered for comparison.

FIGURE 9 .
FIGURE 9 .Comparative plot for buildings with and without shear walls of (a) bending moments (b) Shear forces for columns

Table 1 :
shows the bending and shearforce of columns for building shear wall system.Figure11shows the comparative plots for the same.

TABLE 1 .
Bending moment and shear force of columns