Caltrans engineers have learned lessons from every major seismic event and continue to refine that knowledge today. Caltrans’ retrofit program after the Sylmar earthquake was limited to tying structures together using restrainers at the bridge joints. By the mid-1980’s, additional seismic retrofit methods were researched and developed and our knowledge of the effects of seismic activity continued to evolve.
Caltrans Seismic Retrofit Program.
After the Northridge quake, California’s Seismic Activity Board reported that the 60 bridges retrofitted in the Los Angeles area during the 1980’s performed well. Since then, our work to strengthen the state’s aging bridges has continued and today we have completed retrofitting more than 2,200 bridges on the state highway system. While recognizing that bridges will likely be damaged by significant quake activity, the goal of our seismic retrofit program is to preserve life by preventing bridge collapse.