Third Street Bridge Rehabilitation, San Francisco, CA

TRC was retained by the City and County of San Francisco Public Works to provide design, environmental documentation and construction support services for the Third Street Bridge Rehabilitation project. The historic Third Street Bridge over Mission Channel, commonly known as the Lefty O’Doul Bridge, is a single leaf, heel trunnion type bascule span bridge designed by Joseph Strauss. The bridge is 295-feet-long and 81-feet-wide including sidewalks, with a single 143-foot-long Pratt through truss movable span, five south approach spans and a single north approach span. The structure carries five lanes of traffic, four through the truss and one which is cantilevered on the west side of the structure. The deck on the lift span is open grid steel with steel plates on the east side which were added for pedestrian traffic. In addition, the bridge has sidewalks on both sides and carries many pedestrians, especially during Giants baseball games.

TRC led a multi-disciplined team of structural, bridge and environmental engineers to perform a physical inspection of the bridge above and below the waterline; perform preliminary engineering studies and prepare preliminary design drawings; obtain environmental clearance and permitting; provide design and development of the 65%, 95% and 100% submittals along with the Final PS&E; and provide support to public works during the bidding, award process and construction support activities.

Included in the scope of the project, TRC developed a detailed 3-D model of the structure in order to perform a live load rating analysis of the truss members, floor beams and stringers as well as a gusset plate analysis using LRFR criteria. 3-D modeling was also performed in LUSAS to develop demands and custom spreadsheets were developed to compute the capacities and rating factors.

Located in the heart of San Francisco, this project was considered by many to be the highest profile job in the City due to the bridge’s proximity to the San Francisco Giants ballpark and the Chase Center, home to the Golden State Warriors basketball team.