Dynamic Analysis of Multistorey framed structure with roof tower

DYNAMIC ANALYSIS

OF

MULTISTOREY FRAMED STRUCTURE

WITH ROOF TOWER

Guide :- Mr. PRAMOD TIWARI

PRESENTED BY: Amit Ranjan (2002309) Gupta Abhishek (2002964) Mohit Jain (2002355) Navdeep Kumar (2002357) Siddhant Raturi (2002403) Vipin Thapliyal (2002854)

INTRODUCTION

• Telecommunication structure designed for supporting parabolic antennas. e.g. microwave transmission for communication , radio and T.V signals.

• Self-supporting structures.

• Three-legged and Four-legged space trussed structures.

• Consideration of load. Seismic load. Wind load.

OBJECTIVES

Modeling of the tower.

Modeling of the building.

Study of the Response Spectra Method on the building with roof tower.

Study of the wind load on the building.

BUILDING USED

Building usedHeight of the building = 9.9 mNo. of storey 3

Tower 4 legged space tower height of the tower = 15m

1. Type of structure Multi-storey rigid jointed framed structure

2. Seismic zone Zone -IV

3. Number of stories Three ( G+2 )

4. Floor height 3.3 m

5. Infill wall250 mm thick including plaster in longitudinal and 150 mm in transverse direction

6. Imposed load 3 kN/m2

7. Materials Concrete ( M 25) and reinforcement (Fe 500)

8.Size of columns

460 mm x 340 mm

530 mm x 340 mm

450 mm x 340 mm

9. Size of beams450 mm x 230 mm

300 mm x 230 mm

10. Depth of slab 150 mm thick

11. Specific weight of RCC 24 kN/m3

12. Specific weight of infill 20 kN/m3

13. Type of soil Medium soil

14. Response spectra As per IS 1893 ( part 1): 2002

15. Time historyCompatible to IS 1893 ( part 1): 2002 spectra at medium soil for 5% damping.

Detailing of Building

1. Type of structure 4-Legged Steel Structure

2. Seismic zone Zone –IV

3. Height 15 m

4. Base Width 2.1 m

5. Poisson’s ratio 0.3

6. Young’s modulus of elasticity, Es2.11 x 105MPa

7. Materials Steel ISA 50X50X6

ISA 40X40X6

8. Axial Force 10KN in comp.

4KN in ten.

Detailing of Tower

GEOMETRY

GENERAL

PROPERTY SUPPORTS LOAD &

DEFINITION

CROSS SECTION

FIXED AND PINNED

DEFINITION

DYNAMIC LOAD

RESPONSE SPECTRA METHOD

LOAD CASE & DETAILS

ANALYSE

STEPS INVOLVED IN WORKING OF STAAD- PRO

RESPONSE SPECTRA

Response spectra is a very useful tool of earthquake engineering for analysing the performance of structure during earthquake. Response spectra is simply a plot of the peak or steady state response (disp., vel., ace.) Response spectra is measured using accelerograph.

RESPONSE SPECTRUM METHOD BY USING STAADPRO

The design lateral shear force at each floor in each mode is computed by STAAD in accordance with the IS: 1893 (Part 1) -2002

STAAD utilizes the following procedure to generate the lateral seismic loads.

[1] User provides the value for as factors for input spectrum. I* Z / 2 R

[2] Program calculates time periods for first six modes or as specified by the user.

[3] Program calculates Sa/g for each mode utilizing time period and damping for each mode.

[5] The program then calculates mode participation factor for different modes.

[6] The peak lateral seismic force at each floor in each mode is calculated.

[7] All response quantities for each mode are calculated.

[8] The peak response quantities are then combined as per method (CQC or SRSS or ABS ) as defined by the user to get the final results

[4] The program calculates design horizontal acceleration spectrum for different modes

RESPONSE SPECTRUM DATA SPECIFICATION

Mode shapeMode shape is the deformed shape of the building when shaken at natural period

Factors influencing Mode Shapes

(1)Effect of Flexural Stiffness of Structural Elements

(2) Effect of Axial Stiffness of Vertical Members

(3) Effect of Degree of Fixity at Member Ends

(4) Effect of Building Height

Wind :Wind is the term used for air in motion and is usually applied to the natural horizontal motion of the atmosphere.

Types of wind:1. Prevailing wind

2. Seasonal wind

3. Local wind

Design analysis of wind :

Design Wind Speed (Vz) :

Vz = Vb k1 k2 k3

Vz = design wind speed at any height z in m/s, k1 = probability factor (risk coefficient) k2 = terrain roughness and height factor k3 = topography factor

Design Wind Pressure (pz):

pz = 0.6 vz2

pz = wind pressure in N/m2 at height z, and Vz = design wind speed in m/s at height z.

1) 1.5(DL+LL) 2) 1.2(DL+LL) 3) 1.2(DL+LL+EQX)4) 1.2(DL+LL-EQX) 5) 1.2(DL+LL+EQZ) 6) 1.2(DL+LL-EQZ)7) 1.5DL8) 1.5(DL+EQX) 9) 1.5(DL+EQZ) 10) 1.5(DL-EQX) 11) 1.5(DL-EQZ) 12) 0.9DL+1.5EQX13) 0.9DL+1.5EQZ14) 0.9DL-1.5EQX15) 0.9DL-1.5EQZ

LOAD COMBINATIONS CONSIDERED IN THIS ANALYSIS ARE

PLAN

ELEVATION

PLAN AND ELEVATION OF STRUCTURE 1

PLAN

ELEVATION

PLAN AND ELEVATION OF STRUCTURE 2

PLAN

ELEVATION

PLAN AND ELEVATION OF STRUCTURE 3

0

12

Beam No.

Dis

pla

cem

ent

(mm

439 451 452 454 5580

0.5

1

1.5

Column No.

Dis

pla

cem

ent

(mm

)

CALCULATIONS FOR THE DISPLACEMENT OF BEAMS AND COLUMNS

FOR STRUCTURE 1

47648150951151253453591591791891992101234

Beam No.

Dis

pla

cem

en

t (m

m)

441 444 445 447 4500

0.5

1

1.5

2

Column No.

Dis

pla

cem

en

t (m

m)

FOR STRUCTURE 2

457

459

464

470

496

903

907

909

0

1

2

3

4

5

6

Beam No

Dis

pla

cem

en

t (m

m)

433 436 437 438 4390

0.5

1

1.5

Column No.

Dis

pla

cem

en

t (m

m)

FOR STRUCTURE 3

1. The displacement of structure 2 and 3 are more than that of structure 1 by comparing their graphical values which are generated with the help of software.

2. As the height of the building is 9.9 m and according to IS code the wind load is applied on the structures whose height is more than 10 m ,So there is no need of applying wind load.

RESULT AND CONCLUSION

Max. Displacement of beams and columns for structure with tower at 1st position

BEAM 486 488 489 493 494 498 499 537

MAX DISPLACEMENT 0.678 0.337 0.887 0.467 0.22 0.256 0.636 1.054

BEAM 540 917 918 919 920 921 922

MAX DISPLACEMENT 1.835 0.155 0.755 0.145 0.191 0.629 0.037

486

488

489

493

494

498

499

537

540

917

918

919

920

921

922

00.5

11.5

2

Beam No.

Dis

pla

cem

ent

(mm

)

439 451 452 454 5580

0.5

1

1.5

Column No.

Dis

pla

cem

ent

(mm

)

COLUMN 439 451 452 454 558

MAX DISPLACEMENT 1.224 1.143 0.815 0.861 0.602

REFERENCES

IS - 1893 – 2002 (part - 1)

IS - 875 (part - 3)

Bhosale N.Kumar P., Pandey A.D., (2012), Influence of Host Structure Characteristics on Response of Rooftop Telecommunication Towers, International Journal of Civil and Structural Engineering, 2(3), 2012.

Siddhesha H., (2010), Wind analysis of Microwave Towers, International Journal of Applied Engineering Research, Dindigul, 1(3), 574-584. Amiri G., Barkhordari M.A., Massah S. R., Vafaei M.R.,(2007), Earthquake Amplification Factors for Self-supporting 4-legged Telecommunication Towers, World Applied Sciences Journal, 6(2), 635-643.

McClure G., Georgi L., Assi R, (2004), Seismic considerations for telecommunication towers mounted on building rooftop, 13th World Conference on Earthquake Engineering, Vancouver, Canada, Paper No. 1988.

THANK

YOU