Low Cost Shape Memory Alloy Devices for Seismic Response Modification of Light-Frame Wood Buildings

摘要

Light-frame wood buildings have performed well with regard to life safety during recent U.S. earthquakes with several exceptions being the Loma Prieta and Northridge earthquakes. In these earthquakes, particularly Northridge, there was substantial damage resulting from several and perhaps even a single large amplitude inter-story drift during seismic excitation. Designing buildings to be more resilient to earthquakes is the impetus for the study presented in this paper. Architectural features and the ever-increasing demand for larger (and more) windows reduces the strength and stiffness of light-frame wood structures necessitating alternative procedures to be considered. An alternative procedure is developed and presented in this paper. Superelastic shape memory alloys (SMA's) which have been shown to perform well as energy dissipation devices thereby improving the response of civil engineering systems to earthquakes, are applied to modify the response of light-frame wood building systems with large openings. Fragility curves and design charts for a range of seismic weights and desired performance levels are developed for a portfolio of SMA walls to be treated as replacement walls for wood shear walls in design or retrofit. The design of a large custom residential building using this technology is presented and performance verification is achieved using nonlinear time history analysis.