wind excitation control in skyscrapers by using the damper on intermediate floor. Using Indian standard codes analysis and coefficients were developed. The simulation is done in multiple software like Rhino-grasshopper,Ansys-fluent,Etab.

1. Wind Excitation
Control on
Skyscraper
By Prashant S. Borge
Seat no:5867
Guided by Dr. Sumant Kulkarni
Co-guide by Abhijeet Galatage

2. Skyscraper

3. Classification
• Tall-300m
• Supertall -300-600m
• Megatall – above 600m

4. Wind

5. Wind effect on structure
• Vortex shedding
• Buffeting
• Flutter
• Ovaling

6. • Vortex shedding

7. • Buffeting

8. • Galloping

9. • Ovalling

10. Objective :
• To check the drag coefficient of the modified
skyscrapers.
• To check wind excitation in the structure.
• To reduce the wind excitation in the structure by tune
mass damper.

11. LITERATURE REVIEW• Huang and Li et al. [9] experimented with building height and the natural vibration frequencies to
the predominant frequencies of the strong dynamic loads. The general inflow turbulence generator
for large eddy simulation was based on the discretizing and synthesizing of random flow
generation techniques. They used method which was able to generate a fluctuating turbulent flow
field satisfying desired spectra and spatial correlations including inhomogeneity and anisotropy. It
was found that combined methods fluid dynamics and solid structure dynamics computing help to
resolve detailed wind induced responses on high rise building.
• Torino and Corso [10] analyzed high rise structure for horizontal forces distribution. Wake
shapes were investigated by means of computational fluid dynamics [CFD] analysis. It was
observed that due to vortex created, when wind interact with the façade corners in these point a
separation airflows occurs creating air vortex. Also in twisting tower, it was found that positive and
negative coefficient values were varying along lateral sides of tower.
• Merrik and Bitsumlak [11] studied bluff bodies that plays important role in aerodynamic
principal response of high rise building. The dynamic loads and computed inertial loads
were then combined to provide the peak design loads. The scaled aerodynamic model was
light and rigid to avoid any resonance effect due to modal vibration and spectral response
due to high damping. They concluded square seed building had generated a torsion effect
two times greater than the circular building. Wind phenomena such as vortex shedding
generate high dynamic load and elliptical, triangular and rectangular shaped building were
identified as being more susceptible to high torsion loading.
• Mohotti and Danushka [14] experimented on free standing tall building of height 350m
which were irregular in shape with base diameter of 38 m. The tetrahedral mesh was
generated in Ansys Fluent for large eddy simulation modelling with K-ε solving method. The
first mode fundamental frequency could be larger than 0.2Hz.Wind significantly retarded to
a minimum at the face of the building surface and at the wake it formed a vortex. They
concluded that pressure increase along the height of the building was directly proportional
to velocity profile of wind.

12. • Nagarjaih and Vardhrajan [5] investigated the effectiveness of SAIVS-TMD for the response
control of a wind excited building. They considered a 76 storey 306m high concrete slender tower
with height-width ratio of 7.3. They developed EMD instantaneous frequency algorithm. They
concluded that TMD losses its effectiveness with 15% stiffness variation.
• Salvi, Rizzi et al. [6] optimized tuning of passive Tuned Mass Damper devices at given seismic
input signal. They considered five earthquake events and five shear-type frame structures. The
factors like frequency ratio, damping ratio were considered for analysis. They also used algorithms
available in MATLAB, which were based on Sequential Quadratic Programing (SQP) for tuning of
dampers. They concluded that an average reduction of about 18% was obtained for response of
structure with added TMD.
• Sinan and Bekads [7] investigated harmonic algorithm to find optimum mass ratio, period and
damping ratio of tuned mass dampers. The dampers were implemented on structures with
different periods and damping ratios. The authors concluded that the optimum damping ratio of
TMD was maximum for structures with 1.5-4.0 sec period. Also the best reduction of displacement
was observed for structures with period 1.0-1.5s and 3.0-3.5s.
• Said and Matsagar [8] investigated on 76 storey building was modeled as shear type structure
with lateral degree of freedom at each floor, and tune mass damper were installed at top storey of
building. They were used Newmark’s method to solve governing equation of motion of structure.
They concluded that MTMD were effectively performed vibration control under the wind load than
the STMD.

13. • Shape
• Single chamfered
• Double chamfered
• Twisting

14. • Single chamfered
0
2
4
6
8
10
12
0 0.2 0.4 0.6 0.8 1 1.2 1.4
H/b ratio
Coefficient of drag
0.05
0.1
0.15
0.2
0.25
a/B

15. • Double chamfered
0
2
4
6
8
10
12
0 0.5 1 1.5 2
H/b ratio
Coefficient of drag
0.05
0.1
0.15
0.2
0.25
a/B

16. • Twisting
0
2
4
6
8
10
12
0 0.5 1 1.5
H/b ratio
Drag coefficient
90°
180°
270°
360°

17. PRESENT STUDY

18. PASSIVE ENERGY
CONTROL METHOD
• TUNED MASS DAMPER

20. METHODOLOGY
1. Determine the mass and stiffness parameters, M and k of the primary system.
2. Specify the required modal damping ζ of the considered mode of primary system.
3. Calculate the damping ratio of secondary system.
2d 
4. Calculate the mass ratio.
2
2
2
1 2
d
d





5. Calculate the angular frequency of secondary system
1
.
1
d o 



6. Calculate Md,Cd and kd
Md= µ.M
2
.d d dk M
2
.
2. . .
d d d
d d d d
k M
C k M





21. RESULT AND
DISCUSSION
• FORCE ALONG DIRECTION
• FORCE ACROSS DIRECTION
• TORSION
• LATERAL DISPLACEMENT
• STORY DRIFT
• WIND SHEAR

22. • FORCE ALONG
DIRECTION

23. • FORCE ACROSS
DIRECTION

24. • TORSION

25. • LATERAL
DISPLACEMENT

27. 0
20
40
60
80
100
120
DISPLACEMENT
(MM)
STATIC LATERAL DISPLACEMENT X
DIRECTION
WTMD
0.50%
1%
2%
5%
DOUBLE
CHAMFERED

28. 65
70
75
80
85
90
DISPLACEMENT(
MM)
DYNAMIC LATERAL DISPLACEMENT X
DIRECTION
WTMD
0.50%
1%
2%
5%
Single chamfered Double
chamfered

29. Lateral
displacement in
top of storey in Y
direction(mm)
WTMD ζ=0.5% ζ=1% ζ=2% ζ=5%
Single chamfered 82.5 82.0 81 80.8 72.2
Double chamfered 69.5 69.3 69.0 67.6 57.6
efficiency 15.7 15.4 14.8 16.3 20.2
0
20
40
60
80
100
DISPLACEMENT
(MM)
STATIC LATERAL DISPLACEMENT IN Y
DIRECTION
WTMD
ζ=0.5%
ζ=1%
ζ=2%
ζ=5%
Single
chamfered
Double
chamfered

30. • STORY DRIFT

31. • Wind shear

32. • Damped time period
Single
chamfered
Damped
frequency(Hz)
Tuning
ratio
Double
chamfered
Damped
frequency
(Hz)
Tuning
ratio
0.5% 0.367 0.847 0.5% 0.404 0.933
1% 0.366 0.845 1% 0.404 0.933
2% 0.323 0.745 2% 0.405 0.935
5% 0.359 0.829 5% 0.396 0.914

33. • Conclusion
• The along and across direction force will be reduced at amount 9.17% and 6.28% due to 5% increase
damping of tuned mass damper. The rotational angle of skyscraper reduced in single chamfered
structure is 16.67% in static analysis and dynamic analysis 12.4%. The rotational angle of skyscraper
reduced in double chamfered skyscraper is 17.14% in static analysis and 15% in dynamic analysis.
• The lateral displacement in the skyscraper in X direction is reduced by providing MTMD of ζ-5% the
lateral displacement in X direction in single chamfered model in static condition reduced by 15.75% and
dynamic 13.19%.The lateral displacement in X direction in double chamfered model in load static
conditions 11.21% and dynamic 12.51%.
• The single chamfered building story drift is also considerably are reduces due to high damping ratio. For
5% damping ratio, the storey drift in X direction for 5% damping ratio single chamfered model reduced by
8.737% and double chamfered model 19.23%.
• The wind shear is reduces due to MTMD in the skyscraper. For 5% damping ratio, the wind shear in X
direction reduced due MTMD by single chamfered model 62.47% and double chamfered model 36.76%.
• The MTMD installation the damped time period increased in single chamfered skyscraper 98.23% and for
double chamfered skyscraper 99.24%, for increment of 5% in tune mass damper. The tuning ratio limit is
0.5-1.25. The single chamfered skyscraper the 2% increased damping is gives less tuning ratio. The
double chamfered skyscraper the 5% increased damping is gives less tuning ratio.
• The drag coefficient of single chamfered skyscraper is 0.1 ratios (chamfered width/base width). For
double chamfered skyscraper is 0.15ratios (chamfered width/base width). The twisting skyscraper
structure at 270° is less drag coefficient.

34. • Reference
• Tamura Y.,Kim Y.,Tanaka H.(2013), “Aerodynamic and Response Characteristic of Super
Tall Building with Various Configuration” The Eighth Asia-pacific Conference on wind
engineering , Chennai,India, pp. K219-K243
• Mohotti D.,Danushka K.,Mendis P(2015), “Wind Design of Slender Tall Building : CFD
Approach”. ICECM, pp. 194-203
• Mendis P., Ngo. T., Haritos N.(2007) “Wind Loading on Tall Buildings” EJSC, pp. 41-54
• Ahuja A.,Amin J.(2010), “ Aerodynamic Modification to the Shape of the Building”,Asian
Journal of Civil Engineering,Vol.11 pp. 433-450.
• NagarJanuary S.,VardhraJanuary N.(2004) “ Wind Response Control of Building With
Variable Stiffness TMD”, Journal of Engineering Mechanics, pp. 451-458.
• Salvi J.,Rizzi E.,Govazzeni M.(2014), “ Analysis of Optimum Performance of TMD
Devices”,9thInternationalConferenceonStructuralDynamics, Porto,Portugal, pp. 1729-
1736.
• Sinan M., Bekade G.(2010), “Application of TMD to Control Vibration”,Journal Of
Engineering, pp. 116-124.
• Said E.,Matsagar V.(2014), “Distribute Multiple TMD for Wind Vibration Response Control
of High Rise Building, Journal of Engineering , pp. 1-11.
• Codes
• IS 875(part-3)1987, code of practice for design loads (other than earthquake)for building
and structures(part 3)wind loads(Third Revisions).
• ETAB-pro user guide.

35. • Tall Building structural systems and Aerodynamic form, Mehemet Halis Gunel and
Huseyin Emre Ilgin.
• Wind and Earthquake resistant building structural analysis and design, Bungale
S.Tarnath (Ph.D), S.E. John a. martin and associates Inc.
• https://www.gerb.com/
• http://www.deicon.com/tuned-mass-dampers
• http://global.ctbuh.org
• http://www.arup.com/tall_buildings
• http://rwdi.com

36. •Thank you