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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
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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 • Occurs naturally in structures • Microcracks • Microslip among frictional interfaces • Joints 7 November 2012, EERI, Rice Chapter
Damping – SDOF system • SDOF – Single Degree of Freedom System 7 November 2012, EERI, Rice Chapter
Critical damping 7 November 2012, EERI, Rice Chapter
Spectrum 7 November 2012, EERI, Rice Chapter
Spectrum 7 November 2012, EERI, Rice Chapter
Multi Degree of Freedom System 7 November 2012, EERI, Rice Chapter
Tuned mass damper 7 November 2012, EERI, Rice Chapter
Tuned mass damper 7 November 2012, EERI, Rice Chapter
Tuned mass damper 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. 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. 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. 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. 7 November 2012, EERI, Rice Chapter
MR dampers (no damper) 7 November 2012, EERI, Rice Chapter
MR dampers (1 damper) 7 November 2012, EERI, Rice Chapter
MR dampers (>1 damper) 7 November 2012, EERI, Rice Chapter
Viscoelastic dampers 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. Wallace F. Bennet Building, Salt Lake City, Utah, USA 7 November 2012, EERI, Rice Chapter
Friction dampers 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). Constantinou, MC and Symans, MD, (1993), “Seismic response of structures with supplemental damping,” The Structural Design of Tall Buildings, vol. 2, 77-92. 7 November 2012, EERI, Rice Chapter
Friction dampers Patient Tower, Seattle, USA Monterey County Govt. Center, Monterey County, 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. 7 November 2012, EERI, Rice Chapter
Damping force - summary Friction Dampers Steel yielding device Viscoelastic device 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. 7 November 2012, EERI, Rice Chapter
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.
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. 7 November 2012, EERI, Rice Chapter