Evaluation of Fluid Dampers for Seismic Energy Dissipation of Woodframe Structures

For the 1994 Northridge, California Earthquake, it has been estimated that there was in excess of $20 billion dollars worth of damage to woodframed buildings. Such structures have generally received minimal attention from the earthquake engineering research community. One reason for this lack of attention is that such structures are considered to carry relatively small seismic forces due to their high strength-to-weight ratio and due to their inherent ability to dissipate energy. However, such structures have experienced significant damage during strong earthquakes to the extent that they are no longer capable of serving their function. Thus, there is a need for a cost-effective method by which light-framed wood buildings could be protected from strong earthquakes such that they remain intact with minimal damage.

The primary objective of this research project is to investigate the suitability of fluid viscous dampers for seismic protection of light-framed wood buildings. The objective was met by developing nonlinear finite element models of wood building components (shearwalls) and systems (three-dimensional houses) and performing numerical analysis to evaluate their seismic response with and without fluid dampers. In addition, some of the practical issues associated with implementation of fluid dampers within light-framed wood buildings have been explored. The results of the numerical study clearly demonstrate the ability of fluid dampers to dissipate a significant amount of seismic input energy, relieving the inelastic strain energy demand on the structure.