Investigation of Optimal Seismic Design of Typical Bridges in Colorado

In 2009, new American Association of State Highway and Transportation Officials (AASHTO) Guide Specifications for load rating factor design (LRFD) Seismic Bridge Design were introduced, based on a target displacement to achieve certain performance levels. States now have the option of using the new guide specifications or AASHTO's previous elastic force-based guidelines. Historically, Colorado has put little consideration into seismic design of bridges, due to seismicity being less of a concern than it is in seismic-prone states. The goal of this study of to increase the awareness of seismic risk of bridges in Colorado and identify the best seismic design methodology to follow in future bridge designs.