7 november 2012, eeri, rice chapter
DESCRIPTION
Introduction to Damping and Dampers. Vishnu PhD Candidate Dept. of Civil and Environmental Engineering Rice University, Houston, TX. 7 November 2012, EERI, Rice Chapter. Fundamentals. Three fundamental properties of any structure Mass, m Stiffness, k Damping, c - PowerPoint PPT PresentationTRANSCRIPT
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7 November 2012, EERI, Rice Chapter
Introduction to Damping and Dampers
VishnuPhD Candidate
Dept. of Civil and Environmental EngineeringRice University, Houston, TX
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7 November 2012, EERI, Rice Chapter
Fundamentals
• Three fundamental properties of any structure– Mass, m– Stiffness, k– Damping, c
• Occurs naturally in structures– Microcracks– Microslip among frictional interfaces– Joints
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7 November 2012, EERI, Rice Chapter
Damping – SDOF system
• SDOF – Single Degree of Freedom System
0 2 4 6 8 10 12 14 16-100
-50
0
50
100
150Single Degree of Freedom System
Time (secs)
Inp
ut a
nd
Ou
tpu
t
Input acceleration
Output - = 5%
Output - = 10%
Output - = 20%
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7 November 2012, EERI, Rice Chapter
Critical damping
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7 November 2012, EERI, Rice Chapter
Spectrum
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7 November 2012, EERI, Rice Chapter
Spectrum
0 1 2 3 40
0.02
0.04
0.06
0.08
0.1
0.12
0.14
0.16
0.18
0.2
/p
x/x o
0 1 2 3 40
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
/p
Ba
se s
he
ar/
We
igh
t
= 1% = 5% = 10% = 20%
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7 November 2012, EERI, Rice Chapter
Multi Degree of Freedom System
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7 November 2012, EERI, Rice Chapter
Tuned mass damper
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7 November 2012, EERI, Rice Chapter
Tuned mass damper
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7 November 2012, EERI, Rice Chapter
Tuned mass damper
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7 November 2012, EERI, Rice Chapter
Fluid dampers
Constantinou, MC, Symans, MD, (1999) “Experimental study of seismic response of buildings with supplemental fluid dampers,” The Structural Design of Tall Buildings, Vol. 2, 93-132.
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7 November 2012, EERI, Rice Chapter
Fluid dampers
Constantinou, MC, Symans, MD, (1999) “Experimental study of seismic response of buildings with supplemental fluid dampers,” The Structural Design of Tall Buildings, Vol. 2, 93-132.
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7 November 2012, EERI, Rice Chapter
Fluid dampers
Constantinou, MC, Symans, MD, (1999) “Experimental study of seismic response of buildings with supplemental fluid dampers,” The Structural Design of Tall Buildings, Vol. 2, 93-132.
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7 November 2012, EERI, Rice Chapter
Fluid dampers
Constantinou, MC, Symans, MD, (1999) “Experimental study of seismic response of buildings with supplemental fluid dampers,” The Structural Design of Tall Buildings, Vol. 2, 93-132.
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Constantinou, MC, Symans, MD, (1999)
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Constantinou, MC, Symans, MD, (1999)
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7 November 2012, EERI, Rice Chapter
MR dampers (no damper)
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7 November 2012, EERI, Rice Chapter
MR dampers (1 damper)
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7 November 2012, EERI, Rice Chapter
MR dampers (>1 damper)
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7 November 2012, EERI, Rice Chapter
Viscoelastic dampers
Wallace F. Bennet Building, Salt Lake City, Utah, USA
Kaiser Santa Clara Medical Hospital, Santa Clara, California, USA
Symans, MD et al., (2008) “Energy Dissipation Systems for Seismic Applications: Current Practice and Recent Developments,” J. of Struct. Engrg, vol. 134, No.1, 3-21.
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7 November 2012, EERI, Rice Chapter
Friction dampers
Constantinou, MC and Symans, MD, (1993), “Seismic response of structures with supplemental damping,” The Structural Design of Tall Buildings, vol. 2, 77-92.
Nagarajaiah, S. et al. (1992) “Experimental study of sliding isolated structures with uplift restraint,” J. Struct. Engrg., vol. 118, no. 6, 1666-1682. (page no. 1678).
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7 November 2012, EERI, Rice Chapter
Friction dampers
Monterey County Govt. Center, Monterey County, California, USA
Patient Tower, Seattle, USA
Symans, MD et al., (2008) “Energy Dissipation Systems for Seismic Applications: Current Practice and Recent Developments,” J. of Struct. Engrg, vol. 134, No.1, 3-21.
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7 November 2012, EERI, Rice Chapter
Damping force - summary
a) Friction Dampersb) Steel yielding
devicec) Viscoelastic
deviced) Viscous device
Constantinou, MC and Symans, MD, (1993), “Seismic response of structures with supplemental damping,” The Structural Design of Tall Buildings, vol. 2, 77-92.
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Symans, MD et al., (2008) “Energy Dissipation Systems for Seismic Applications: Current Practice and Recent Developments,” J. of Struct. Engrg, vol. 134, No.1, 3-21.
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Symans, MD et al., (2008)
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7 November 2012, EERI, Rice Chapter
Summary
• Supplemental damping can be provided and is very effective.
• When choosing a supplemental damping strategy scaling is a very important phenomenon that needs to be taken into account.