Three Mile Slough and Steamboat Slough Bridges
Sacramento Delta, California
Client:
California Department of Transportation
Date:
Design Completed 1995
Scope of work:
Seismic Retrofit Design
Construction cost:
N/A
Services Performed:
- Seismic retrofit design studies
Issues:
- Seismic retrofit of lift bridge
- Seismic retrofit of bascule bridge
- Steel member capacity evaluation
OPAC was a subconsultant to DeLeuw, Cather & Company to perform seismic engineering services for the existing Three Mile Slough Vertical Lift Bridge and the Steamboat Slough Bascule Bridge for the California Department of Transportation (Caltrans). OPAC's work scope for the project included:
- Modeling approach consultation.
- Steel member capacity evaluation.
- Seismic retrofit strategy development.
These two bridges were characterized by Caltrans as "difficult" seismic retrofits. OPAC provided guidance on modeling issues pertaining to these moveable bridge systems, determined the capacities of built-up, latticed, and rolled steel members, and assisted in retrofit strategy development.