Nominee: On Time – Large Project
“We are celebrating a milestone for one of the most crucial and challenging public works projects in California’s history. The mile-long West Approach requires mind-boggling construction and engineering feats. And I could not be prouder of our incredible workers who made this space of the bridge a reality, and not only a reality but a full seven months ahead of schedule.”
The San Francisco-Oakland Bay Bridge West Approach structure is in the heart of a rapidly growing mixed residential and commercial neighborhood in San Francisco known as South of Market. The seismic retrofit-by-replacement of the one-mile stretch of Interstate 80 – ten lanes of west and eastbound roadway and associated off- and on-ramps – had to be done within the footprint of the original structure while not reducing mainline capacity during peak commute periods. Complicating the construction was the fact that portions of the structure are within inches of existing buildings. Caltrans, under the direction of the Toll Bridge Program Oversight Committee, and the prime contractor effectively worked together to eliminate significant delays to the project; the project was completed seven months ahead of schedule and within its $429 million budget.
Through innovative engineering, and design, the project was able to minimize right-of-way impacts and loss of key freeway lanes during commuting hours. Each deck of the new structure was constructed on an independent foundation system to maximize survivability during a major seismic event. The new foundation system had to be solidly embedded into the bedrock, which required using deep piles.
The original structure lacked shoulders and the 11-foot wide travel lanes were narrower than the currently mandated 12-foot width, which resulted in potential gridlock during minor traffic incidents. The new structures were designed with standard width lanes and 10-foot wide shoulders on both sides of the roadway, greatly improving operations and safety. Routine maintenance operations on the corridor can now be performed without closing one traffic lane, thus improving the operational aspect of the corridor.
Caltrans implemented a comprehensive array of erosion control measures to ensure the stability of the hillsides adjacent to, and impacted by, the project. Drought tolerant trees, shrubs and ground cover will be planted in all available “green space” within the project limits to provide seasonal interest and to compliment and soften the structural elements of the project. Architectural lighting will also be installed as an additional aesthetic component. As a result of Caltrans’ extraordinary investigation effort, more than 125,000 artifacts, as well as floral and faunal specimens, were collected and cataloged during the West Approach archaeology project and are currently at Sonoma State University.