810 Fifth Ave. – Suite 100 San Rafael, CA 94901
The infamous Doyle Drive built in 1936, and known as the most dangerous highway in the State of California, was redesigned in 2009 and re-named the Presidio Parkway. The shoring for the excavation of the new Southbound Battery Tunnel, a cut-and-cover tunnel that is 30 ft. to 40 ft below the original grade, was originally designed using 3 levels of struts. The General Contractor could see that this would impede the construction of the tunnel and hired PB&A to design a CRIP (Cost Reduction Incentive Proposal). PB&A used a creative design that employed one level of struts and one level of tiebacks. A very stringent deflection criteria was mandated due to the close proximity of the tunnel to the adjacent Veterans Administration Cemetery.
During Construction a Caltrans Official was heard to say, “The site is becoming quite impressive with the shoring walls now supporting a deep excavation. I think the CRIP redesign did save the contractor a lot time and hassle by not having to deal with multiple layers of struts and should facilitate the construction of the tunnel walls going back up.”