International Research Journal of Engineering and Technology (IRJET)
e-ISSN: 2395-0056
Volume: 06 Issue: 03 | Mar 2019
p-ISSN: 2395-0072
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SEISMIC ANALYSIS FOR VERTICALLY GEOMETRIC IRREGULARITY USING E-TABS K. Vamsi Krishna 1, k. Naga Poojitha 2, L. Mohan Kumar 3, K. Krishna Mohan 4, R. Leela krishna sai 5 ,P. Girish sai kumar6 1Assistant
professor in Civil Engineering, Dhanekula institute of engineering& Technology, Ganguru, Andhra Pradesh. 2, 3,4,5,6
students in civil engineering, D.I.E.T, Ganguru, Andhra Pradesh.
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Abstract - During an earthquake, failure of structure starts
from the points of weakness. This type of weakness arises due to discontinuity in mass, stiffness and geometry of structure. Vertically irregular structure is nothing but the discontinuities in the vertical plane of the structures. To construct any structure safety plays a very important role, in that a building must resist for earthquake. For a regular or for a simple structure damage due to earthquake will be minimum but irregularity makes structures vulnerable under seismic loading. In this present study G+5 building located in zone II, III, IV are analyzed using ETABS software for vertical geometric irregularity. In order to find out the seismic response of the structure for in three different zones, it is important to obtain the plan of the structure and to analyze various elements of a building such as beam, column, slab, foundation and stair case under the seismic load acting on the structure. The structure was analyzed with various combination as per code IS1893:2002 part-1. We also used the AUTOCAD for our designs of the structures. The main advantage of displacing the drawing in AutoCAD is user has more flexibility to modify the drawings in AutoCAD. KEYWORDS: seismic load, G+5, Zones, Auto CAD, E-TABS.
In the shape point of view, The buildings can are broadly categorized as regular and irregular buildings. The irregularity of a building can be depends on the stiffness, discontinuity in plane or geometry, mass or load resisting elements. The structural irregularities can be broadly categorized as horizontal and vertical irregularity. The different factor that causes damage to the structure throughout the earthquake are mass irregularity, vertical irregularities, torsional irregularity, irregularity in strength and stiffness, etc. Generally in multi-storied RC framed buildings, The destruction stats from the point of weakness. In some of the cases, these weaknesses are also developed by discontinuities in stiffness, strength or mass between adjacent stories.
1.1 Necessity of the study Seismic analysis of a building has now become an important part in present senario of modern structural designs, it is because earthquake causes lots of damages and loss of life. Multi-storey structures constructed by reinforced cement concrete are subjected to severe actions of seismic waves during earthquake. The main reason for the failure of RC building is irregularity in geometry. The irregularities may be in its plan dimension, lateral force distribution.
1.INTRODUCTION Earthquakes are natural hazards, Generally earthquakes are mainly caused by the collision of tectonic plates, some other natural disasters like volcanic eruptions and other manmade structures. For new constructions, establishing earthquake resistant regulations and their implementation experience is the critical safeguard against earthquake induced damage. when constructing an vertically irregular structures the structural engineers role becomes more difficult than others. Before we going to construct a structure evaluation is important. The analysis and design is must and should for every irregular structures, that gives the result whether the structure is safe or not. Š 2019, IRJET
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2. METHODOLOGY Following steps of methods are adopted in this project: Step-1: Selection of the structure and three different seismic zones like II, III, IV. Step-2: Collection and study of literatures Step-3: Plan representation in CAD software Step-4: Export to ETABS Step-5: Assigning of loads and load combinations Step-6: Seismic analysis and design for the data model Step-7: Interpretation of results.
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International Research Journal of Engineering and Technology (IRJET)
e-ISSN: 2395-0056
Volume: 06 Issue: 03 | Mar 2019
p-ISSN: 2395-0072
www.irjet.net
Table -1: S. No
Content
Type of structure
1
Shape of the building Number of storey Height of the floor
2 3 4
5
Materials
Description
No of Stories 5 4 3 2 1 Ground Base
Vertical geometric irregularity Asymmetrica l G+5
Zone 2 344.342 298.7901 266.728 139.494 39.8936 0.4885 0
Zone 3 550.9472 478.0642 426.7648 223.1904 63.8298 0.7816 0
Zone 4 826.4209 717.0962 640.1471 334.7856 95.7447 1.1724 0
3.0m Table-2 Base shear along y-direction in three different zones:
Concrete (M25), Steel(Fe415)
6
Wall thickness
300mm
7
Beam size
230*450mm
8
Column size
300*550mm
9
Depth of slab
150mm
10
unit weight of RCC Live load
25kN/m3
11
Table-1 Base shear along x-direction in three different zones:
No of stories 5 4 3 2 1 Ground Ground Base Base Base
3.0kN/m2
Zone 2
Zone 3
344.342 298.7901 266.728 139.494 39.8936 0.4885 0
550.9472 478.0642 426.7648 223.1904 63.8298 0.7816 0
Zone 4 826.4209 717.0962 640.1471 334.7856 95.7447 1.1724 0
Model considered in the project
GRAPH-1,2 BASE SHEAR IN BOTH X & Y DIRECTIONS FOR THREE ZONES
Fig -1: G+5 Vertical Geometric Irregularity
3. RESULTS Results for base shear, displacement and drift on both X and Y directions are represented graphically for three different zones
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International Research Journal of Engineering and Technology (IRJET)
e-ISSN: 2395-0056
Volume: 06 Issue: 03 | Mar 2019
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Table-3 Displacement along x-direction for three different zones: No of Stories 5 4 3 2 1 Ground Base
Zone 2
Zone 3
Zone 4
0.001 0.001 0.000449 0.000296 0.000144 1.54E-05 0
0.001 0.001 0.001 0.000474 0.000231 2.46E-05 0
0.002 0.002 0.001 0.001 0.0003459 3.69E-05 0
Table-4 Displacement along y-direction for three different zones: No Of Stories
Zone 2
Zone 3
Zone 4
5 4 3 2 1 Ground Base
0.001 0.001 0.001 0.000348 0.000165 1.69E-05 0
0.001 0.001 0.001 0.001 0.000263 2.71E-05 0
0.002 0.002 0.001 0.001 0.000395 4.07E-05 0
Table-5 Storey Shear in zone II: No. of stories
Elevati on
Locatio n
Storey 5
15.45 15.45 12.45 12.45 9.45 9.45 6.45 6.45 3.45 3.45 0.45 0.45 0 0
Top Bottom Top Bottom Top Bottom Top Bottom Top Bottom Top Bottom Top Bottom
Storey 4 Storey 3 Storey 2 Storey 1 Ground Base
No. of stories
Elevati on
Locatio n
xdirectio n (mm)
ydirectio n (mm)
Storey 5
15.45 15.45 12.45 12.45 9.45 9.45 6.45 6.45 3.45 3.45 0.45 0.45 0 0
Top Bottom Top Bottom Top Bottom Top Bottom Top Bottom Top Bottom Top Bottom
-550.947 -550.947 -1029.01 -1029.01 -1455.78 -1455.78 -1678.97 -1678.97 -1742.8 -1742.8 -1743.58 -1743.58 0 0
-550.947 -550.947 -1029.01 -1029.01 -1455.78 -1455.78 -1678.97 -1678.97 -1742.8 -1742.8 -1743.58 -1743.58 0 0
Storey 3 Storey 2 Storey 1 Ground Base
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ydirectio n (mm) -344.342 -344.342 -643.132 -643.132 -909.86 -909.86 -1049.35 -1049.35 -1089.25 -1089.25 -1089.74 -1089.74 0 0
Table-6 Storey Shear in zone III:
Storey 4
GRAPH-3,4 STOREY DRIFT IN BOTH X&Y DIRECTIONS FOR THREE ZONES
xdirectio n (mm) -344.342 -344.342 -643.132 -643.132 -909.86 -909.86 -1049.35 -1049.35 -1089.25 -1089.25 -1089.74 -1089.74 0 0
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International Research Journal of Engineering and Technology (IRJET)
e-ISSN: 2395-0056
Volume: 06 Issue: 03 | Mar 2019
p-ISSN: 2395-0072
www.irjet.net
Table-7 Storey Shear in zone IV: No. of stories
Elevati on
Locatio n
Storey 5
15.45 15.45 12.45 12.45 9.45 9.45 6.45 6.45 3.45 3.45 0.45 0.45 0 0
Top Bottom Top Bottom Top Bottom Top Bottom Top Bottom Top Bottom Top Bottom
Storey 4 Storey 3 Storey 2 Storey 1 Ground Base
xdirectio n (mm) -826.421 -826.421 -1543.52 -1543.52 -2183.66 -2183.66 -2518.45 -2518.45 -2614.19 -2614.19 -2615.37 -2615.37 0 0
ydirectio n (mm) -826.421 -826.421 -1543.52 -1543.52 -2183.66 -2183.66 -2518.45 -2518.45 -2614.19 -2614.19 -2615.37 -2615.37 0 0
3.Akhilesh rathi, Dr. Ashwin Raut, “Design and analysis of regular and vertical irregular building by using ETABS”, (ISSN NO:2249-7455). 4. Devesh P. soni and bhartha B. mistry ." Qualitative review of seismic response of vertically irregilar building Frames ". ISET Journal of Earthquake Technology, Vol43, No.4, December 2006, PP 121- 132. 5. Ilham Salehi, Dr. Raman Nateriya, “seismic evaluation of vertical irregular building with setback”, vol5 issue-6,June 2018. 6. Rahul, Shivanand C G, “Study of vertical irregularity of tall rc structure under lateral load”, vol4 issue-8, august 2017. 7. Lakshmi Subash, “seismic behaviour of vertically irregular reinforced concrete buildings with p-delta effect”, vol4 issue-4, April 2017. 8. Dileshwar Rana, Prof. juned Raheem, “seismic analysis of regular & vertical geometric irregular RCC framed building”, vol2 issue-4,July 2015. 9. Poonam, Anil kumar and Ashok K.Gupta "Study of response of stucturally irregular buildimng frames to seismic excitation ". 10.Ankit Purohit, Lovishpamecha, “seismic analysis of G+12 multistory building varying zone and soil type, vol4 issue-6, June 2017.
GRAPH-5,6 FOR STOREY SHEAR AT THREE DIFFERENT ZONES ALONG X-DIRECTION AND Y-DIRECTION
11. Himanshu Bansal, Gagandeep, “seismic analysis and design of vertically irregular RC building frames”, (ISSN:2319-7064).
4. CONCLUSIONS
12. Vikas joshi, “Dynamic analysis of vertical varying irregular building with response spectrum”, vol8 issue1, January 2018.
• In this study, we have mainly considered storey displacement, storey drift, Axial lateral load and Storey shear for the building and analysed by using E-tabs as per the specification IS 1893:2002(part1).
13.Anil kumar S Katageri, Sharanabasava G, “seismic performance study of R.C. buildings having vertical geometric irregularity using pushover analysis”, vol3 issue-11, 2016.
• It can be concluded that, Base shear, storey displacement, storey shear and storey drift will increases as the earthquake intensity increases from zone II, zone III, zone IV.
6.REFERENCES 1. shaikh A. Aijaj, G.S. Deshmukh, ‘’Seismic analysis of vertically irregular building’’ (ISSN:2277-8594), July 2016. 2. Kusuma B, “seismic analysis of a high-rise framed structure with irregularities”, vol 4 issue-7,July 2017.
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