Yerba Buena Island Transition Structure
THE YERBA BUENA ISLAND TRANSITION STRUCTURE (YBITS)
The Yerba Buena Island Transition Structure (YBITS) will connect the Self-Anchored Suspension Span (SAS) to Yerba Buena Island (YBI), and will transition the new East Span’s side-by-side road decks to the upper and lower decks of the YBI tunnel and West Span.
Crews face the challenge of building the YBITS without disrupting traffic. To accomplish this daunting task, eastbound and westbound traffic were shifted off the original roadway over YBI and onto a temporary detour during Labor Day weekend in 2009. The detour, built by prime contractor CC Myers, connects the East Span traffic to the tunnel. Drivers are using the detour, just south of the original roadway, until traffic is moved onto the new East Span. Due to a conflict between the YBITS and the original East Span, traffic was routed to the detour so crews can demolish the conflicting portion of the bridge leading to the YBI tunnel, and build the YBITS while traffic safely travels adjacent to the construction. MCM Construction is the prime contractor on the YBITS.
Crews are particularly careful during construction as to protect YBI’s rich military history, which dates back to the 1800s. YBI, which currently has an active coast guard station, saw its first military post and depot built in 1868. Since then the island has hosted a torpedo station (the torpedo shed still stands on the eastern shore) and a U.S. Naval Training Station. Many of those structures remain, including the Nimitz House, a classic revival-style naval commandant’s house used by Admiral Nimitz during World War II.
- Forms link between the SAS and the Yerba Buena Island Tunnel
- 7,600 tons of steel in the YBITS
- Made up of 13 supports (footings and columns)
- Transitions side-by-side roadways on the SAS to upper and lower decks of the tunnel
- 23,936 cubic meters of concrete make up the YBITS
- Length: 1,542 ft (470 meters)
- A new 300-foot-long viaduct was installed Labor Day weekend 2007
- An elevated detour was put into place Labor Day weekend 2009