YERBA BUENA ISLAND TRANSITION STRUCTURE
Traducción al Español de esta página.
The Yerba Buena Island Transition Structure (YBITS) will connect the Self-Anchored Suspension (SAS) span to Yerba Buena Island (YBI), and will transition the East Span’s side-by-side road decks to the upper and lower decks of the YBI tunnel and West Span.
As with all of the Bay Bridge’s Seismic Retrofit Projects, crews must build the YBITS close to moving vehicles without disrupting traffic. To accomplish this daunting task, eastbound and westbound traffic were shifted off the existing roadway over YBI and onto a temporary detour during Labor Day weekend in 2009. The detour connects 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.
The first in a series of phases to build the temporary 900-foot-long detour, as well as the YBITS, took place during Labor Day weekend in 2007. During this historic milestone, the entire Bay Bridge was closed—for the first time since the Loma Prieta earthquake—so crews could replace a 350-foot-long, 6,500-ton section of viaduct on YBI, just before the tunnel. Crews replaced this with a seismically upgraded section of roadway that will serve as a connection to both the YBITS and detour. This marked the completion of the first part of the new bridge that drivers are already using.
YBI TEMPORARY DETOUR
Shifting traffic to this temporary detour will allow crews to attach the western end of the SAS span to the tunnel. This shift to the temporary detour has been the most significant realignment on the bridge to date. To accomplish this, crews cut away a 288-foot-portion of the existing truss bridge and replaced it with a connection to the detour. This maneuver completed over Labor Day weekend in 2009, was the most dramatic operation yet and involved aerial construction occuring more than 100 feet above YBI. Vehicles will travel on the detour until the completion of the new East Span. More on the Labor Day closure here
