Comparison of RC Shear Wall with Openings in Regular and Irregular Building

Comparison of RC Shear Wall with Openings in Regular and Irregular Building

Abhija Mohan1

1PG Scholar Sree Buddha College of Engineering, Alapuzha Pathanamthitta cluster of APJ Abdul Kalam

Technological University,

Ayathil, Elavumthitta P.O, Pathanamthitta-689625

Arathi S2

2Assistant Professor Sree Buddha College of Engineering, Alapuzha Pathanamthitta cluster of APJ Abdul Kalam Technological University,

Ayathil, Elavumthitta P.O, Pathanamthitta-689625

Abstract – Shear walls are structural systems which provide stability to structures from lateral loads like wind, seismic loads. An attempt is made to apply the finite element modelling in analyzing and exploring the behavior of shear wall with opening under seismic load actions. Shear walls are generally located at the sides of buildings or arranged in the form of core that houses stairs and lifts. The properties of these seismic shear walls dominate the response of the buildings, and therefore, it is important to evaluate the seismic response of the shear walls appropriately. Due to functional requirements such as doors, windows, and other openings, a shear wall in a building contains many openings. In this present study, the main focus is to determine effectiveness of shear wall with vertical opening and staggered opening in regular and irregular buildings under earthquake loads with the help of finite element software, ETABS.

Key Words: Shear wall, ETABS, Seismic behavior, Storey drift etc.

of a building, because of lateral loads. They act as vertical cantilevers to give the essential stiffness in a building.

Shear walls may have one or more openings for functional reasons such as doors, windows, and other types of openings in shear wall. Openings can be arranged vertically or in staggered manner as shown in fig1.The size and location of openings may vary depending on purposes of the openings. Properly designed and detailed buildings with shear walls have shown good performance in past earthquakes.

1. INTRODUCTION

   In modern high rise buildings, shear walls are generally used as a vertical structural element for resisting the lateral loads that is induced by the effect of wind and earthquakes, they will have the strength and stiffness to resist the horizontal forces. Seismic waves reasons arbitrary ground motions in all possible directions, transmitting from the epicentre. If the structure has not been designed to resist these additional forces it may fail causing loss of life and property. In this way the impacts of sidelong loads like wind loads, quake forces & impact loads, etc. are achieving growing significance and every design engineer will face the issue of giving sufficient strength & stability for the structures against the imposed total lateral loads.

   Lateral forces caused by wind, earthquake, and uneven settlement loads, in addition to the weight of structure and occupants; create powerful twisting (torsion) forces. These forces can literally tear (shear) a building apart. Reinforcing a frame by attaching or placing a rigid wall inside it maintains the shape of the frame and prevents rotation at the joints. Shear wall are specially designed structural walls in building to resist lateral forces that are produce in the plane of wall due to wind, earthquake and other forces. Shear walls not only help to prevent catastrophic collapse, but they also help to prevent small- scale damage like cracked drywall and fractured tile. Shear walls play the same role in houses in high-wind zones. Shear walls are utilized to withstand the bending moments

   Fig:1 Shear wall without opening and with vertical and staggered opening

2. OBJECTIVES

   1. To determine the effect of vertical and staggered openings in RC shear wall in a regular building under seismic loads

   2. To study the behavior of vertical and staggered openings in RC shear wall in a irregular building under seismic loading

   3. Comparison of effect of openings in regular and irregular building.

3. LITERATURE VIEW

   S.H.Jagadale , N.L. Shelke (2016)[9] studied the "Analysis of Various Thicknesses of Shear Wall with Opening and without Opening and their Percentage Reinforcement. In this paper the effectiveness of shear wall with various thicknesses, and also vertical opening, staggered opening and without opening has been studied and found that performance of staggered opening is better in seismic zone as compared to vertical opening and without opening in shear wall.

   Aarathi Harini T and G Senthil Kumar (2015)[1] analysed a seven storey building without opening, with vertical openings, and with staggered openings. The study was carried out using linear elastic analysis, with the help of finite element software ETABS, using response spectrum method. The comparative results showed that the time period, displacement, base shear and stress distribution around the openings depend on the arrangement of openings. They concluded that staggered openings in shear wall proved to be highly advantageous and they were found to provide better lateral resistance than shear walls with vertical openings.

   N. Janardhana Reddy, D. Gose Peera, T. Anil Kumar Reddy (2015)[6] presented a study on Seismic Analysis of Multi-Storied Building with Shear Walls Using ETABS- 2013. In this work a high rise building with different places of shear walls is considered for analysis. The multi storey building with 14 storeys is analyzed for its displacement, strength and stability using ETABS-2013 software. It is evident that shear walls which are provided from foundation to the roof top, are one of the excellent mean for providing earthquake resistance in high rise buildings.

   Arvind R. Patel, Dr. K. B. Parikh (2015)[2] studied the Effect on Location of Shear Wall with Opening in RC Irregular Structure Subjected to Seismic Load & blast load. A study on an irregular high rise building with shear wall was studied to understand the lateral loads, story drifts and torsion effects. From the results it is inferred that optimum shear walls are more resistant to lateral loads in an irregular structure.

   Sharmin Reza Chowdhury, M.A. Rahman, M.J.Islam (2012)[8] studied the Effects of Openings in Shear Wall on Seismic Response of Structures. This study is carried out on 6- story frame-shear wall buildings, using linear elastic analysis with the help of finite element software, ETABS under earthquake loads in equivalent static analysis. The results reveal that stiffness and seismic responses of structures is affected by the size of the openings as well as their locations in shear wall.

4. METHODOLOGY

1. Modelling of Building

   Here the study is carried out for the behaviour of G+10 storied RC building with shear wall in regular and irregular plans. Floor height provided 3m. And also the properties are defined for the structure.

2. Building plan and dimensional details

The Following are the specification of G+ 10 storied RC building located in seismic zone V resting on medium soil type. The complete detail of the structure including modelling concepts is given Table 1. Buildings modelled using ETABS are shown in Fig: 2 to Fig:13

Table1: Structural data required for analysis

Fig 2: Plan of Regular Building with shear wall

Fig.3 Regular building model with shear wall having vertical opening

Fig.4 Regular building model with shear wall having staggered opening

Fig 5: Plan of H shaped Building with shear wall

Fig 6: H shaped Building model with shear wall having vertical opening

Fig 7: H shaped Building model with shear wall having staggered opening

Fig 8: Plan of L shaped Building with shear wall having vertical opening

Fig 9: L shaped Building model with shear wall having vertical opening

Fig 10: L shaped Building model with shear wall having staggered opening

Fig 11: Plan of T shaped Building with shear wall having vertical opening

Fig 12: T shaped Building model with shear wall having vertical opening

Fig 13: T shaped Building model with shear wall having staggered opening

C. Assigning loads

• Dead load

  Dead load intensity = 1.5 kN/m2

• Live load

  Live Load Intensity specified (Public building) = 3kN/m2

• Wall weight

  Wall weight = 12 kN/m

  V SEISMIC ANALYSIS OF BUILDING

  1. Seismic parameters considered (as per 1893(PART 1): 2002)

Table 5.1: Parameters considered for seismic analysis

VI ANALYSIS RESULTS

1. Displacement, Storey drift and Base shear of G+10 regular building

   Graphical representation of displacement, storey drift and base shear values are shown in Fig: 14 to Fig16

   40

   DISPLACEMENT

   20

   VERTICAL

   STAGGERED

   0

   RSX

   RSY

   Fig: 14 Variation of displacement for regular building with vertical and staggered opening

   STOREY DRIFT

   0.002

   VERTICAL

   0

   RSX RSY

   STAGGER

   ED

   Fig: 15 Variation of storey Drift for regular building with vertical and staggered opening

   5000

   BASE SHEAR

   VERTICAL

   0

   RSX RSY

   STAGGER

   ED

   Fig: 16 Variation of Base shear for regular building with vertical and staggered opening

2. Displacement, Storey drift and Base shear of G+10 L shaped building

   Graphical representation of displacement, storey drift and base shear values are shown in Fig: 17 to Fig: 19

   DISPLACEMENT

   50

   VERTICAL

   0

   RSX RSY

   Fig: 17 Variation of displacement for L shaped building with vertical and staggered opening

   STOREY DRIFT

   0.002 VERTICAL

   0.001

   0

   RSX

   RSY

   STAGGERE

   D

   Fig: 18Variation of storey Drift for L shaped building with vertical and staggered opening

   BASE SHEAR

   3500

   3000

   2500

   VERTICAL

   STAGGERED

   2000

   RSX RSY

   Fig: 19 Variation of base shear for L shaped building with vertical and staggered opening

3. Displacement, Storey drift and base shear of G+10 H shaped building

   Graphical representation of displacement, storey drift and base shear values are shown in Fig: 20 to Fig: 22

   DISPLACEMENT

   18 VERTICAL

   16

   14

   0.002

   STAGGERE

   D

   0.001

   RSY

   RSX

   0

   STOREY DRIFT

   VERTICAL STAGGERED

   VERTICAL

   0.0006

   0.00055

   0.0005

   Fig: 20 Variation of storey displacement for H shaped building with vertical and staggered opening

   STOREY DRIFT

   0.00065

   RSX RSY

   VERTICAL

   5400

   5200

   5000

   4800

   STAGGERE

   D

   Fig: 21 Variation of Storey Drift for H shaped building with vertical and staggered opening

   BASE SHEAR

   D

   RSY

   RSX

   STAGGERE

   Fig: 22 Variation of Base shear for H shaped building with vertical and staggered opening

4. Displacement, Storey drift and Storey shear of G+10 T shaped building

Graphical representation of displacement, storey drift and base shear values are shown in Fig: 23 to Fig: 25.

DISPLACEMENT

40

VERTICAL

20

0

RSX

RSY

STAGGERE

D

Fig: 23 Variation of storey displacement for T shaped building with vertical and staggered opening

RSX RSY

Fig: 24 Variation of Storey Drift for T shaped building with vertical and staggered opening

BASE SHEAR

4200

4000

3800

3600

3400

3200

VERTICAL

STAGGERED

RSX RSY

Fig: 25 Variation of storey shear for T shaped building with vertical and staggered opening

VII. CONCLUSIONS

The present study focuses to determine effectiveness of shear wall with vertical opening and staggered opening in regular and irregular buildings under earthquake loads with the help of finite element software, ETABS. The G+10 storied rectangular, L, H and T shaped buildings with shear wall having vertical and staggered openings are analysed using response spectrum analysis. From the above study, following conclusions were drawn.

• G+10 regular building with shear wall having staggered opening shows better dynamic behaviour based on displacement (percentage reduction of 12.92% in X direction and 13.15% in Y direction compared to vertical openings), storey drift (percentage reduction of 11.176% in X direction and

  12.307 in Y direction compared to vertical openings) and base shear (percentage reduction of 12.53% in X direction and 13.13% in Y direction compared to vertical openings) values in X and Y directions.

• G+10 L shape building with staggered opening shows better performance in terms of displacement (percentage reduction of 11.239 % in X direction compared to vertical openings) and base shear (percentage reduction of 0.44% compared to vertical openings) in X- direction. But L shaped building with shear wall having vertical opening shows better performance in terms of displacement (percentage reduction of 5.4% compared to staggered openings) and base shear (percentage reduction of 13.37% compared to staggered openings) in Y direction.

• Shear wall with staggered opening shows better performance compared to shear walls with vertical openings in H shaped G+10 building based on displacement (percentage reduction of 8.17% in X direction and 7.75% in Y direction compared to vertical openings), storey drift (percentage reduction of 6.739% in X direction and 6.98% in Y direction compared to vertical openings) and base shear (percentage reduction of 0.896% in X direction and 0.401% in Y direction compared to vertical openings) values in both X and Y directions.

• Shear wall with staggered opening shows better performance compared to shear walls with vertical openings in T shaped G+10 building based on displacement (percentage reduction of 5.99% in X direction and 5.8% in Y direction compared to vertical openings), storey drift (percentage reduction of 4.65% in X direction and 7.51% in Y direction compared to vertical openings) and base shear (percentage reduction of 4.676% in X direction and 4.69% in Y direction compared to vertical openings) values in both X and Y directions.

Hence we can concuded that regular building with shear wall having staggered opening shows better results in terms of displacement, storey drift and storey shear. In the case of irregular buildings (H shaped and T shaped) buildings with staggered opening shows better results in terms of displacement, storey drift and storey shear in both X and Y directions. But in case L shaped irregular building, building with shear wall having vertical openings shown good results in terms of displacement and base shear in Y direction.

REFERENCES

1. Aarthi Harini T, G. Senthil Kumar (2015) Behavior of R.C. Shear Wall with Staggered Openings under Seismic Loads, International Journal for Research in Emerging Science and Technology,vol.2 issue 3, March 2015.

2. Arvind. R. Patel, Dr. K. B. Parikh (2015) Effect on Location of Shear Wall with Opening in RC Irregular Structure Subjected to Seismic Load & blast load , International journal of innovative research in technology.

3. IS 1893, Indian Standard criteria for Earthquake Resistant Design of structures Part 1: General Provisions and Buildings, Fifth Revision, Bureau of Indian Standards (BIS), New Delhi, 2002.

4. IS 875, Indian Standard Code of Practice for Design Loads (Other Than Earthquakes) For Building and Structures Part 1: Dead Loads

   Unit Weights of Building materials and stored materials,Second Revision, Bureau of Indian Standards (BIS), New Delhi, 1987.

5. IS 875, Indian Standard Code of Practice for Design Loads (Other Than Earthquakes) For Building and Structures Part 2: Imposed Loads, Second Revision, Bureau of Indian Standards (BIS), New Delhi, 1987.

6. N. Janardhana Reddy, D. Gose Peera, T. Anil Kumar Reddy (2013), Seismic Analysis of Multi-Storied Building with Shear Walls Using ETABS-2013, International Journal of Science and Research (IJSR)

7. Sachin.P.Dyavappanavar, Dr. K.Manjunatha, Kavya N (2015) Effects of Openings in Shear Wall on Seismic Response of Structures International Research Journal of Engineering and Technology (IRJET).

8. Sharmin Reza Chowdhury , M.A. Rahman, M.J.Islam (2012) Effects of Openings in Shear Wall on Seismic Response of Structures, International journal for research in engineering, science and technologies.

9. S.H.Jagadale , N.L. Shelke (2016) Analysis of Various Thicknesses of Shear Wall with Opening and without Opening and their Percentage Reinforcement, International Journal of Computer Applications(0975 8887) Volume 59 No.1, December 2012

ACKNOWLEDGEMENT

I am thankful to my guide, Asst. Professor, Arathi.S in Civil Engineering Department for her constant encouragement and able guidance. Also I thank my parents, friends etc. for their continuous support in making this work complete.