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 bySourabh Kumar Shubham Borkar

Under the guidanceProf. Sudhir Kapgate

Aim Objective Introduction Assumptions Plan Aspect ratio Slenderness ratio Literature Survey Methodology References

CONTENTS

AIM

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

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.

INTRODUCTION

Definition of flat slab :Flat slab is a reinforced concrete slab supportedBy columns with or without drops & columnHead.

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.

Flat slab with drop panel & column head

ASSUMPTIONS

STRUCTURE Multi- Storied R.C.C. Flat slab Structure NUMBER OF STOREY 11 PLAN DIMENSIONS

• AREA 1200 m2 • COLUMN SPACING

IN X DIRECTION 6mIN 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)

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

METHOD OF ANALYSIS RESPONSE SPECTRUM METHOD LOAD CASES

PLAN ASPECT RATIO (L/B)•AREA CONSTANT = 900 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 30 30 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

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

Width Of Building Constant

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 0.41M12 5 21.60 0.612M13 7 28.80 0.823M14 9 36.00 1.034M15 11 43.20 1.235

6

M2

M21

2

3 14.40 0.577 M22 5 21.60 0.868 M23 7 28.80 1.159 M24 9 36.00 1.4410 M25 11 43.20 1.7311

M3

M31

3

3 14.40 0.7212 M32 5 21.60 1.0813 M33 7 28.80 1.4414 M34 9 36.00 1.815 M35 11 43.20 2.16

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.

ANALYSIS OF 11 STOREY R.C. STRUCTURE

PLAN ASPECT RATIO (L/B)= 1

SLENDERNESS RATIO (H/B)= 0.96

ANALYSIS OF G+11 STOREY R.C. STRUCTURE

PLAN

LITERATURE SURVEYS.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, bs or euro code to design and analyze flat slabs/plates .

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.

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.

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.

METHODOLOGYSR.NO SEMESTER ACTIVITY DURATION1. 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

•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

THANK YOU