This presentation highlights the effect of Fluid Viscous Dampers (FVDs) on the seismic performance of adjacent buildings connected through a ped-way. A part of this project also deals with the Qualitative Damage Analysis of the structure during an earthquake, with and without FVDs.

1. STUDY ON SEISMIC PERFORMANCE OF
ADJACENT BUILDINGS USING FVDs
CIV E 661- Dynamics of Structures
UNIVERSITY OF ALBERTA
Group Members
Course ID
Ayaz Malik
Luong Hong
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2. OBJECTIVES
 To study the effect of Fluid Viscous Dampers (FVDs)
on response of adjacent buildings during a past
earthquake (El Centro).
 To perform Qualitative Damage Analysis of the
structure under earthquake excitation, with and
without FVDs.

3. SPECIFICATIONS FOR ANALYSIS
AND DESIGN
 ACI 318-08, Building Code Requirements for
Structural Concrete
 AISC 360-05, Specification for Structural Steel
Buildings
 IBC (International Building Code), 2009
 ATC-40 Report on Seismic Evaluation and Retrofit of
Concrete Buildings, Volume 1
COMPUTER SOFTWARE USED: SAP 2000 Ver. 14

4. BUILDING MODEL
 Number of Stories = 11
 Storey height = 14 ft
 Bay width = 20 ft
 fc’ (Columns) = 4000 Psi
 fc’ (Beams/Slabs) = 3000 Psi
 fy (Reinforcement) = 60, 000 Psi
 fy (Steel beams) = 250 MPa
 Typical Beam Size = 18 x 21 in
 Typical Column Size = 24 x 24 in
 Slab Thickness = 6 in

5. LOADINGS FOR ANALYSIS
 Partition load = 20 lb/ft2
 Live Load = 80 lb/ft2
 Earthquake load = El Centro
Step size = 0.1 sec , Number of steps = 3000 (Chopra)
-0.4
-0.3
-0.2
-0.1
0
0.1
0.2
0.3
0.4
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32
Acceleration(g)
Time (sec)

6. ANALYSIS CASES
Case 1 Case 2
Case 3 Case 4
Building 2Building 1

7. ANALYSIS CASES
Case 5 Case 6
Case 7

8. FVDs consist of a closed cylinder filled with viscous fluid.
The movement of a piston in that cylinder causes a
friction and energy of the motion can be dissipated. For
non-linear FVDs, the force (𝑓𝐷) - velocity (𝑢) relation is;
𝒇 𝑫 = 𝒄 𝜶 𝒔𝒈𝒏(𝒖) 𝒖 𝜶 (Lin & Chopra, 2002)
Where: 𝒄 𝜶 – damping coefficient (571 Kips-sec/in)
𝜶 – positive exponent, 0.35 – 1.0 (0.5 in model)
sgn(𝑢) – signum function
𝜶 = 1.0 represents the linear FVDs and 𝜶 = 0 represents
the pure friction damper.
FLUID VISCOUS DAMPERS (FVDs)

9. SAN FRANCISCO CIVIC CENTER DAMPER INSTALLATION
(Tylor, Duflot)

10. Sa(g)
Performance Point (Sd, Sa, D)
Sd
Family of Demand Spectra for
different values of damping
Single Demand Curve with
variable damping
Capacity Curve
Acceleration Displacement Response Spectrum
CAPACITY SPECTRUM METHOD
ATC-40 Report on Seismic Evaluation and Retrofit of Concrete Buildings

11. Performance point;
(T = 2.85sec, D = 6.5in)
CAPACITY-DEMAND CURVES FOR
MODEL BUILDING

12. ANALYSIS RESULTS FOR CASES
Case
Deflection (in) No. of
DampersBuilding 1 Building 2
1 12.93 12.93 0
2 7.58 10.95 30
3 6.58 12.39 36
4 5.45 11.54 66
5 7.38 7.39 60
6 6.76 6.78 72
7 5.91 5.9 132
COMPARISON
Between1and6

13. -15
-10
-5
0
5
10
15
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32
RoofDisplacement(in)
Time (Sec)
Without Damping
With Damping
ROOF DISPLACEMENT VS TIME

14. -40
-30
-20
-10
0
10
20
30
40
50
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32
Velocity(in/sec)
Time (sec)
With damping
Without Damping
VELOCITY VS TIME

15. -250
-200
-150
-100
-50
0
50
100
150
200
250
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32
Acceleration(in/sec2)
Time (sec)
With damping
Without Damping
ACCELERATION VS TIME

16. -5000
-4000
-3000
-2000
-1000
0
1000
2000
3000
4000
5000
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32
BaseShear(Kips)
Time (sec)
With Damping
Without Damping
BASE SHEAR VS TIME

17.  Immediate Occupancy, SP-l: A stage where very limited
structural damage has occurred.
 Damage Control, SP-2: A range of post-earthquake damage
states that could vary from SP-I to SP-3.
 Life Safety, SP-3: At this level the risk of life-
threatening injury from structural damage is very low.
 Limited Safety, SP-4: A range of post-earthquake damage
states that are less than SP-3 and better than SP-5.
 Structural Stability, SP-5: A level at which structure is on
the verge of experiencing partial or total collapse.
SEISMIC PERFORMANCE LEVELS
ATC-40 Report on Seismic Evaluation and Retrofit of Concrete
Buildings, Volume 1

18. CASE 1
Roof Displacement > 10 inch
As expected from performance point
displacement, at displacements greater
than 6.5 inch the performance of the
structure became poor. Damage-level
hinges were formed for displacements
greater than 10in which means that the
structure is on the verge of global or
local failure under the given earthquake
load.

19. As the maximum displacement, i.e.
6.8 inch, was very close to
performance point displacement (6.5
inch), Only Immediate Occupancy
level hinges were formed for
displacements lesser than 7 inch.
Thus, for case-6, structure is safe
from stability as well as life safety
point of view under the given
earthquake load.
CASE 6
Roof Displacement < 7 inch

20. • Results showed a significant reduction in lateral
deflection and velocity of the structures when viscous
dampers were added. However, not much improvement
was observed in Acceleration and base shear.
• Their was a significant improvement in performance
level of the structure under earthquake when dampers
were added.
• Optimum level of performance depends on the type of
structure and the level of performance required by
the place holder.
CONCLUSIONS

21. (A California Structural Engineer)
“ WHEN IN DOUBT ……
DAMP IT OUT !! ”

22. ANY QUESTIONS