May 8, 2013
For Immediate Release
Phase II Activity is Heating Up
SAN FRANCISCO - Phase II of construction is underway on the Presidio Parkway. Crews can be seen preparing the project site for construction of major Phase II elements, including the northbound Battery Tunnel, northbound High Viaduct, two Main Post Tunnels, Low Viaduct, and a new interchange to the Marina and the Presidio. The new design will open up views of San Francisco Bay, create new direct access to the Presidio from Doyle Drive, and enhance pedestrian and cyclist connections within the Presidio. Major construction of Phase II is scheduled to be complete in 2015 with an extensive landscaping program to follow through mid-2016.
The first step for the Phase II construction team involves clearing out the project site to make room for the new roadway. Removal of the old High Viaduct is underway; crews are carefully deconstructing the old bridge in the opposite order in which it was originally built. The road deck was first demolished, which will be followed by meticulous removal of the steel truss, then the columns, and finally the foundation of the structure.
To ensure safety during removal of the High Viaduct, there will be overnight closures of Northbound Highway 1 starting Tuesday, May 14. Nighttime work is expected to continue Monday through Saturday for approximately three weeks. Planned closure hours are Monday - Thursday from 12:00 - 4:00 a.m. and Friday - Saturday from 1:00- 4:00 a.m. Detour signage will direct motorists from Highway 1 to Highway 101 via Geary Boulevard/Van Ness Avenue/Lombard Street. These detour routes were selected because they are able to carry a high volume of traffic and use relatively flat streets. The signed detour must be accessible to all vehicles, including large trucks, motor homes, etc.; however, most people will choose their alternate route based on what is most convenient for their trip.
Site preparation is also underway at the site of the future Northbound Main Post Tunnel, where crews are employing Concrete Deep Soil Mixing (CDSM) to stabilize the soil for seismic safety. CDSM uses specialized equipment that functions like an immersion blender to combine cement, water, and soil at depths up to 60 feet. The result is a grid of reinforced soil beneath construction that will prevent settlement or liquefaction during a seismic event.
"We are excited to begin the second and final phase of this historic effort to transform the Presidio waterfront," says Deputy Director for Capital Projects at the San Francisco County Transportation Authority Lee Saage. "We will see a lot of progress in the coming months, starting with removal of the old High Viaduct to make room for construction of the new bridge. The team is now ready to lay the foundation for Phase II of this complex project."
Check out photos of recent activity in the Site Preparation Photo Album.