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Dynamic characteristics of woodframe buildings

Citation

Camelo, Vanessa Sabrina (2003) Dynamic characteristics of woodframe buildings. Dissertation (Ph.D.), California Institute of Technology. http://resolver.caltech.edu/CaltechETD:etd-06092003-150851

Abstract

A database of dynamic characteristics of woodframe buildings was developed through analysis of recorded earthquake response and by forced vibration and shake-table testing. Modal identification was performed on eight sets of strong-motion records obtained from five buildings, and forced vibration tests were performed on five other buildings. The periods identified were sensitive to the amplitude of shaking, due to the reduction in lateral stiffness at stronger shaking levels. The equivalent viscous damping ratios were usually more than 10% of critical during earthquake shaking. A regression analysis was performed on the earthquake and forced vibration test data to obtain a simple, but reasonably accurate, period formula for woodframe buildings at low drift levels (less than 0.1%). Data obtained from the UC San Diego and UC Berkeley full-scale shake-table tests illustrate the shift in periods due to increasing shaking amplitude. Forced vibration tests of the UC Berkeley 3-story building before and after the shake-table tests showed how the periods and modeshapes shift due to damage. A simple analytical model of masses and springs was used to model the UC Berkeley test structure. The effects of diaphragm stiffness and mass distribution assumptions were evaluated and found to have a significant effect on the model torsional response. This model was used to find the equivalent wall stiffnesses giving frequency-response curves that best-fit the experimental data. These spring values were used to quantify the stiffness loss resulting from severe shaking of the structure, and the observed damage corresponded to stiffness losses of over 75%. The correlation between stiffness loss and damage to woodframe buildings has potential structural health monitoring implications.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:damping; dynamics; forced vibration tests; modeling; periods; shake-table tests; system identification; woodframe
Degree Grantor:California Institute of Technology
Division:Engineering and Applied Science
Major Option:Civil Engineering
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Beck, James L. (advisor)
  • Hall, John F. (advisor)
Thesis Committee:
  • Beck, James L. (chair)
  • Hall, John F.
  • Porter, Keith A.
  • Heaton, Thomas H.
  • Duron, Ziyad H.
Defense Date:23 May 2003
Record Number:CaltechETD:etd-06092003-150851
Persistent URL:http://resolver.caltech.edu/CaltechETD:etd-06092003-150851
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:2524
Collection:CaltechTHESIS
Deposited By: Imported from ETD-db
Deposited On:09 Jun 2003
Last Modified:26 Dec 2012 02:52

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