The Oakland Portal's elaborate Beaux Arts façade conceals eight massive fans that draw in fresh air and expel foul air to prevent carbon monoxide buildup in the George A. Posey Tube, an underwater automobile tunnel that runs under Harrison Street between the cities of Oakland and Alameda. One block west sits the Webster Tube Portal, a 1963 structure that serves the same function as the more decorative Oakland Portal. At the time of its construction, the Posey Tube was the largest underground tunnel in the world. George Lucas filmed a scene in the tunnel for THX 1138, Lucas's first feature film.
Designer: Henry H. Meyers
Construction Date: 1925-28
Architectural Style: Beaux Arts derivative/Art Deco
The tube replaced the Webster Street Bridge to Alameda, allowed industrial development of Oakland’s Inner Harbor, and appeased restless divers tired of waiting for water traffic. The Portals (its twin is on the Alameda side) house ventilation equipment, eight huge fans, to exchange stale air for fresh in the tube. One visitor remembers leather belts operating machinery for the fans that looked like industrial strength hair dryers. It was the first underwater tunnel in the world constructed entirely of reinforced concrete. Forms were towed by tugs from Hunters Point in San Francisco. Art Deco in style, each portal has a three-story central section flanked by two hip roof towers, connected with a huge arched industrial sash window (now painted over). Two side piers, with vertical arched openings and decorative grillwork, create a stepped effect.
January 2016 - Posey Tube Renovation Project Begins
Caltrans will perform a historical renovation of the Posey Tube portal buildings and replace the pedestrian handrail inside of the tube. The work will include sandblasting and repainting the buildings, historical renovation of the sidewalks leading up to the portal, and retrofitting the inside of the building. Other work includes installing CCTVs, organizing signs and replacing cobra head lighting with the original historic lighting at the entrances of the Posey and Webster tubes.
- Work will take place at the two portal buildings, in Alameda and in the Jack London district of Oakland.
- In Oakland, scaffolding around the Posey Tube portal building will block parking adjacent to the building along Harrison Street and both sides of 4th. Also, the sidewalk behind the building will be blocked. A Pedestrian Detour will be provided.
- Pedestrian and bicycle access through the Posey tube will be blocked from February to May. A shuttle will be provided and signage indicating how to contact the shuttle will be posted at both entrances to the Posey Tube pedestrian walkways.
Schedule and Updates
The project is scheduled to start construction in January 2016 and to be completed in July 2016.
- Stationary mounted signs and changeable message signs (CMS) will be strategically placed to provide information regarding the project’s closures and detours.