Parametric study of multi storied RCC flat slab structure under seismic effect having different plan aspect ratio and salenderness ratio

1. NAGPUR INSTITUTE OF TECHNOLOGY, NAGPUR
(Department of civil engineering Session 2015-16)
A
Project seminar on
“Parametric study of multi storied R.C.C flat slab structure
under seismic effect having different plan aspect ratio and
slenderness ratio.”
Submitted by
Sourabh Kumar
Shubham Borkar
Under the guidance
Prof. Sudhir Kapgate

2.  Aim
 Objective
 Introduction
 Assumptions
 Plan Aspect ratio
 Slenderness ratio
 Literature Survey
 Methodology
 References
CONTENTS

3. AIM
 Parametric study of multi storied R.C.C. flat slab structure
under seismic effect having different plan aspect ratio and
slenderness ratio.

4. OBJECTIVE
 To calculate design lateral forces on multi-storied R.C.C. Flat slab structure
with regular building configuration in plan but different aspect ratio using
“Response Spectrum Analysis.”
 To calculate and study the response of structure situated in seismic zone IV
and their comparison.
 To determine limit aspect ratio and slenderness ratio for safe and stable
structure.
 To perform analysis using ETABS for static and dynamic analysis.

5. INTRODUCTION
Definition of flat slab :
Flat slab is a reinforced concrete slab supported
By columns with or without drops & column
Head.

6. COMPONENTS OF FLAT SLABS
Drops: To resist the punching
shear which is predominant at the
contact of slab and column support,
the drop dimension should not be
less than one -third of panel length
in that direction.
Column heads: Certain amount of
negative moment is transferred from the
slab to the column at the support. To resist
this negative moment the area at the support
needs to be increased .This is facilitated by
providing column capital/heads flat slab.

7. Flat slab with drop panel & column head

8. ASSUMPTIONS
 STRUCTURE Multi- Storied R.C.C. Flat slab Structure
NUMBER OF STOREY 11
 PLAN DIMENSIONS
• AREA 1200 m2
• COLUMN SPACING
IN X DIRECTION 6m
IN Y DIRECTION 6m
• FLOOR TO FLOOR HEIGHT 3.6m
• COLUMN SIZE (600 mm X 600 mm)
• SLAB THICKNESS 300 mm
• DROP THICHNESS 150mm
• DROP SIZE (1.25mX1.25m)

9.  LOADING
• DEAD LOAD As Per IS 875 ( Part 1)
• LIVE LOAD As Per IS 875 ( Part 2 )
• AT TYPICAL FLOOR 4.0 kN/m2 As per IS 456:2000
• FLOOR FINISH 1.0 kN/m2 As per IS 456:2000
 DATA FOR SEISMIC ANALYSIS
• EARTHQUAKE LOAD As Per IS 1893 (Part 1)-2002
• TYPE OF FOUNDATION Isolated Column Footing
• DEPTH OF FOUNDATION 3.5m
• TYPE OF SOIL Type II, Medium As Per IS 1893
• BEARING CAPACITY OF SOIL 200 kN/m2
• IMPORTANCE FACTOR 1
• PERCENTAGE DAMPING 0.5%
• TYPE OF FRAME Special moment resisting Frame

10.  METHOD OF ANALYSIS RESPONSE SPECTRUM METHOD
 LOAD CASES

11. PLAN ASPECT RATIO (L/B)
• AREA CONSTANT = 1200 M2
• TABLE MODEL GROUP FOR ASPECT RATIO (L:B)
MAIN
GROUP
ASPECT
RATIO
LENGTH WIDTH COLUMN SPACING
L : B L (m) B(m) X(m) Z(m)
M1 1 35 35 6 6
M2 2 49 25 5.85 5.5
M3 3 60 20 5 6
M4 4 60 15 6 5
M5 5 90 18 6.25 6

12. SLENDERNESS RATIO (H/B)
• Various Slenderness Ratio Can Be Obtained By Changing No. Of Storey & Keeping
Width Of Building Constant

13. TABLE MODEL FOR SLENDERNESS RATIO (H:B)
SR.NO
MODEL
GROUP
MODEL
ASPECT
RATIO
NO. OF
STOREY
STOREY
HEIGHT
SLENDERNESS
RATIO
(L:B) G + 3.60 (H:B)
1
M1
M11
1
3 14.40 0.41
M12 5 21.60 0.612
M13 7 28.80 0.823
M14 9 36.00 1.034
M15 11 43.20 1.235
6
M2
M21
2
3 14.40 0.57
7 M22 5 21.60 0.86
8 M23 7 28.80 1.15
9 M24 9 36.00 1.44
10 M25 11 43.20 1.73
11
M3
M31
3
3 14.40 0.72
12 M32 5 21.60 1.08
13 M33 7 28.80 1.44
14 M34 9 36.00 1.8
15 M35 11 43.20 2.16

14. SR.NO
MODEL
GROUP
MODEL
ASPECT
RATIO
NO. OF STOREY
STOREY
HEIGHT
SLENDERNESS
RATIO
(L:B) 3.60 (H:B)
16
M4
M41
4
3 14.40 0.96
17 M42 5 21.60 1.44
18 M43 7 28.80 1.92
19 M44 9 36.00 2.4
20 M45 11 43.20 2.88
21
M5
M51
5
3 14.40 0.8
22 M52 5 21.60 1.2
23 M53 7 28.80 1.6
24 M54 9 36.00 2
25 M55 11 43.20 2.4
TABLE MODEL FOR SLENDERNESS RATIO (H:B)contd.

15. ANALYSIS OF 11 STOREY R.C. STRUCTURE
PLAN ASPECT RATIO
(L/B)= 1
SLENDERNESS RATIO
(H/B)= 1.23

16. ANALYSIS OF G+11 STOREY R.C. STRUCTURE
PLAN

17. LITERATURE SURVEY
S.S. Patil, Rupali A. Sigi(2014) [1]“Flat Slab Construction in India”:
This paper deals with the different type of RCC flat slab structure and design of flat
slab with the help of IS 456:2000 and ACI-381(2) codes.
Conclusion:-
• Design of conventional R.C.C flat plate/slab in India, utilizing Indian codes, has
many shortcomings, which have to be addressed and revised soon.
• Conventional R.C.C structure should be the preferred choice for spans up to 10
meters.
• Until then indian engineers will continue to use indian codes in combination with
other standards like the ACI & euro code to design and analyze flat slabs/plates .

18. Rucha.S.Banginwar, M.R.Vyawahare, P.O.Modani, [2] “Effect of Plan
Configurations on the Seismic Behaviour of the structure By Response
Spectrum Method”
• To evaluate the effect of plan configurations on the response of structure by
RSM(response spectrum method).
• The IS-1893 (Part I: 2002) guidelines and methodology are used to analyse the
problem.
• Behaviour of different geometrical configurations of structure which are located in
the same area during earthquake by RSM.
• More emphasis is made on the plan configurations and its is analysis by RSM.
Conclusion:-
• Plan configurations of structure has significant impact on the seismic response of
structure in terms of displacement, story drift, story shear. The torsion and
displacements were obtained on higher side in some shapes in comparison to other.

19. Prof. K S Sable, Er. V A Ghodechor, Prof. S B Kandekar,
[3]“Comparative Study of Seismic Behavior of Multistory Flat Slab and
Conventional Reinforced Concrete Framed Structures”
• Studied conventional R.C.C building and flat slab building for different floor
height.
• The effect of seismic load has been studied for the two types of building with
different height.
• Observation includes behaviour of structure under effect of seismic loading in
terms of changes in natural time period, base shear, sway moments and column axial
forces
Conclusion:-
• The natural time period increases as the height of building ( No. of stories)
increases, irrespective of type of building viz. conventional structure, flat slab
structure and flat slab with shear wall. However, the time period is same for flat slab
structure and flat slab with shear wall.

20. Mohit Sharma and Dr. Savita Maru (2014),
[4]“Dynamic Analysis of Multistoried Regular Building”:
• Performed the seismic analysis on G+30 storied regular building using STAAD Pro
V8i.
• Performed analysis with both static and a dynamic method as per the parameters
mentioned in IS 1893 2002 part I.
• Compared between two methods of analysis on the basis of Axial Forces, Torsion
and Moment at different nodes and beam.
Conclusion:-
• Result obtained for Dynamic Analysis were higher that the values as obtained by
Static Analysis for the same points and conditions.

21. METHODOLOGY
SR.NO SEMESTER ACTIVITY DURATION
1. VII Review of existing literature by different research 1 month
2. VII Study of IS 1893:2002 and IS 13920 learning
Software ETABS
3 month
3. VII Formulating the assumption stating the scope of
project by considering various parameter
1 month
4. VIII Modeling and analysis of the structure with the help
of software
1 month
5. VIII Comparison of the data obtained after analysis 2 month
6. VIII Understanding the results of analysis, formulating
Conclusion and further recommendation keeping scope of
study in mind
2 month
7. VIII Dissertation writing 1 month

22. • I.S. 456-2000, indian standard code of practice for plain and reinforced concrete, bureau of
indian standard, new delhi.
• Paz. Mario. “Structural dynamics" theory and computation, CBS, publishers and distributors
dayaganj, new delhi.
• Bis-1893, criteria for earthquake resistant design of structures-part-1, general provisions and
buildings, bureau of indian standards, new delhi -2002.
• I.S-13920."Ductile detailing of reinforced structures subjected to seismic force" code of practice
bureau of indian standards, new delhi -1993.
• I.S 4326 – 1993, earthquake resistant design and construction of buildings - code of practice,
bureau of indian standard, new delhi
• SP-16-1980- design aids for reinforced concrete to is-456-1978-bureau of indian standards, new
delhi.
• IS-875-1987.".Indian standard code of practice for structural safety loadings standards Part-1,
2" Bureau of Indian Standards, New Delhi.
• Www.Nicee.Org, the national information centre of earthquake engineering(nicee - established
1999) .
REFRENCES

23. THANK
YOU