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2010 Weidlinger® Associates 1
The Benefits of Using
Viscous Dampers in a
42-Story Building
7 May 2010
Chukwuma Ekwueme, PhD, SE Gary C. Hart, PhD, CE
Kingsley C. Ozegbe Can Simsir, PhD, CE
Gregg E. Brandow, PhD, CE
2010 Weidlinger® Associates
THANK YOUTHANK YOU
2
David LeeDavid Lee
Douglas TaylorDouglas TaylorTaylor Damping Devices
2010 Weidlinger® Associates 3
2010 Weidlinger® Associates 4
Viscous Damper Viscous Damper
2010 Weidlinger® Associates
Viscous Damper: A Weidlinger Project Viscous Damper: A Weidlinger Project
2010 Weidlinger® Associates
2010 Weidlinger® Associates
1971 : Marshall Lew Start of a Great Career & 1971 : Marshall Lew Start of a Great Career &
Modern Earthquake Design of BuildingsModern Earthquake Design of Buildings
9
2010 Weidlinger® Associates
Earthquake Shaking Potential for Southern CaliforniaEarthquake Shaking Potential for Southern California
Source: California Department of Conservation, California Geological Survey
2010 Weidlinger® Associates
Areas shaded in pink have an acceleration of 75%g or higher
Source: U.S. Department of the Interior - U.S. Geological Survey
MCE Ground Motion for 1.0 Sec Spectral AccelerationMCE Ground Motion for 1.0 Sec Spectral Acceleration
2010 Weidlinger® Associates 12
2010 Weidlinger® Associates 13
2010 Weidlinger® Associates 14
“Passive energy dissipation is
an emerging technology that
enhances the performance of
buildings by adding damping
to buildings.”(ASCE/SEI 41-06, pg 280)
2010 Weidlinger® Associates 15
“Passive energy dissipation is
an emerging technologyemerging technology that
enhances the performance of
buildings by adding damping
to buildings.”(ASCE/SEI 41-06, pg 280)
2010 Weidlinger® Associates
In the Last Century in Southern CaliforniaIn the Last Century in Southern California
16
DateDate # of # of
IsolatorsIsolatorsProject / CommentsProject / Comments
19961996 1616 Kaiser Corona w/ base isolatorsKaiser Corona w/ base isolators
19961996 186186 Arrowhead Regional Medical Center w/ base isolatorsArrowhead Regional Medical Center w/ base isolators
19971997 22 Studio Parking Garage, control seismic movementStudio Parking Garage, control seismic movement
19971997 66 Rockwell Bldg 505, control seismic movementRockwell Bldg 505, control seismic movement
19981998 8484 UCLA Knudsen Hall, concreteUCLA Knudsen Hall, concrete
19991999 3232 Nethercutt Collection, Auto MuseumNethercutt Collection, Auto Museum
19991999 6868 LA City Hall, w/ base isolatorsLA City Hall, w/ base isolators
2010 Weidlinger® Associates
Arrowhead Medical Center
2010 Weidlinger® Associates 21
“The forces and deformations in the
energy dissipation devices that
develop during the Design
Earthquake should be
demonstrated to be adequate by
prototype testing in accordance
with Section 9.3.8.”
(ASCE/SEI 41-06, pg 286)
2010 Weidlinger® Associates 22
“The forces and deformations in the
energy dissipation devices that
develop during the Design
Earthquake should be
demonstrated to be adequate by demonstrated to be adequate by
prototype testingprototype testing in accordance
with Section 9.3.8.”
(ASCE/SEI 41-06, pg 286)
2010 Weidlinger® Associates 23
LATBSDC & LA City Design Criteria LATBSDC & LA City Design Criteria
2010 Weidlinger® Associates
OBJECTIVES
25
� Use LATBSDC Design Criteria for Buildings with
Dampers
� Eliminate shear walls and evaluate impact
� Improve typical preliminary design approach
using structural optimization theory
� Compare story drift and acceleration response
for less than 50% in 30 year earthquake
2010 Weidlinger® Associates
� Less displacement . . . over 50% reduction in drift in many cases
� Decreased base shear and inter-story shear, up to 40%
� Much lower “g” forces in the structure. Equipment keeps working and people are not injured
� Reduced displacements and forces can mean less steel and concrete. This offsets the damper cost and can sometimes even reduce overall cost
Why Use Viscous Dampers?Why Use Viscous Dampers?
Viscous Dampers dramatically decrease earthquake induced motion . . .
Hysteresis Loops With & Without DampersHysteresis Loops With & Without Dampers
2010 Weidlinger® Associates
Tuning The Viscous DampersTuning The Viscous Dampers
2010 Weidlinger® Associates
Tuning The Brace with DampersTuning The Brace with Dampers
2010 Weidlinger® Associates 30
2010 Weidlinger® Associates
Typical Plan ViewTypical Plan View
31
2010 Weidlinger® Associates
Building 2BD Peak Top Floor Response for 50% in 50 yr Building 2BD Peak Top Floor Response for 50% in 50 yr
32
2010 Weidlinger® Associates
Periods of Vibration with and without Core Shear WallsPeriods of Vibration with and without Core Shear Walls
33
With Core Shear Walls Without Core Shear Walls
Period
(seconds)Dominant Direction
Period
(seconds)Dominant Direction
1 4.01 East-West Direction 1 5.75 North-South Direction
2 3.53 North-South Direction 2 5.54 East-West Direction
3 2.12 Torsion 3 3.09 Torsion
2010 Weidlinger® Associates
Comparison of Maximum Story Drifts for 43Comparison of Maximum Story Drifts for 43--Year Earthquake Year Earthquake
34
0
100
200
300
400
500
0 0.001 0.002 0.003 0.004 0.005
He
igh
t (f
t)
Story Drift Ratio (in/in)
With Core
Shear Walls
Without Core
Walls
0
100
200
300
400
500
0 0.001 0.002 0.003 0.004 0.005
Height (ft)
Story Drift Ratio (in/in)
With Core
Shear Walls
Without
Core Walls
2010 Weidlinger® Associates
Typical Floor Plan with Viscous Damping DevicesTypical Floor Plan with Viscous Damping Devices
35
1 2
15’-6” 19’-3” 19’-3” 19’-3” 19’-3” 15’-6”
23’-0
”23
’-0”
7’-6
”7’
-6”
23’-0
”23
’-0”
3 3.5 4 5 6
A
B
C
C.5
D
E
F
Typical Damper Location
FRAME A
FRAME F
FR
AM
E 5
FR
AM
E 2N
2010 Weidlinger® Associates
Building 2BNSW Beams and Columns Building 2BNSW Beams and Columns
36
2010 Weidlinger® Associates
EE--W InterW Inter--Story Drifts for 50% in 30 years (ASCE 7)Story Drifts for 50% in 30 years (ASCE 7)
37
0
100
200
300
400
500
0 0.001 0.002 0.003 0.004 0.005
He
igh
t (f
t)
Story Drift Ratio (in/in)
With Core Walls
Without Core Walls (No
Dampers)
Without Core Walls
(Optimized Dampers)
2010 Weidlinger® Associates
Comparison of Maximum Story Drifts for a 43Comparison of Maximum Story Drifts for a 43--Year Year
Earthquake Obtained from Time History AnalysesEarthquake Obtained from Time History Analyses
38
0
100
200
300
400
500
0 0.001 0.002 0.003 0.004 0.005
He
igh
t (f
t)
Story Drift Ratio (in/in)
No Core Walls,
No Dampers
No Core Walls,
Optimized
Dampers
0
100
200
300
400
500
0 0.001 0.002 0.003 0.004 0.005
He
igh
t (f
t)
Story Drift Ratio (in/in)
No Core Walls,
No Dampers
No Core Walls,
Optimized
Dampers
2010 Weidlinger® Associates
EE--W Floor Acceleration for 50% in 30 YearsW Floor Acceleration for 50% in 30 Years
39
-0.15
-0.10
-0.05
0.00
0.05
0.10
0.15
0 5 10 15 20 25 30 35 40 45
Acc
ele
rati
on
(g)
Time (sec)
No Core Walls, No
Dampers
No Core Walls,
Optimized Dampers
2010 Weidlinger® Associates
Wind Loading on Tall BuildingsWind Loading on Tall Buildings
2010 Weidlinger®
Associates
Time History of Wind Loading Time History of Wind Loading
-1.0E+05
-5.0E+04
0.0E+00
5.0E+04
1.0E+05
1.5E+05
2.0E+05
2.5E+05
3.0E+05
0102030405060708090
Time (second)
Be
nd
ing
Mo
me
nt (K
ip-ft)
Moment - CD
Moment - CL
M vector
CD1
020
4060
80100
120140
1600 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
Time (Interval .029 sec)
Win
d L
oa
d (k
ips
)
Wind Lift Force, FL1 (t)
Wind Drag Force, FD2 (t)
Wind Lift Force, FL3 (t)
Wind Lift Force, FL4 (t)
Wind Lift Force, FL5 (t)
Wind Lift Force, FL6 (t)
Wind Lift Force, FL7 (t)
Wind Lift Force, FL8 (t)
Wind Lift Force, FL2 (t)
Wind Drag Force, FD3 (t)
Wind Drag Force, FD4 (t)
Wind Drag Force, FD5 (t)
Wind Drag Force, FD6 (t)
Wind Drag Force, FD7 (t)
Wind Drag Force, FD8 (t)
Wind Drag Forces, FDi (t)
Wind Lift Forces, FLi (t)
CL1
-80-60
-40-20
020
4060
80100
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
Time (Interval .029 sec)
Win
d L
oa
d (k
ips
)
Wind Drag Forces, FD1 (t)
X
Y
2010 Weidlinger® Associates 42
2010 Weidlinger® Associates
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