from "Take A Fresh Look", News Oakland Mayor Jean Quan, Oct. 6, 2012
On September 21, 2012 -- almost exactly two years from the start of tunneling -- all excavation of the Fourth Bore was completed. The tunnel now measures almost 10 meters (33 feet) high and 13 meters (43 feet) wide for its entire length. Crews are currently working around the clock to complete the installation of a waterproof membrane to prevent groundwater seepage, as well as a rebar cage and final lining arch, which will provide both flexibility and strength in the event of an earthquake. The final lining, which requires a total of 69 concrete pours, or "lifts," is what motorists will see as they travel through the tunnel.
There is still much work to be done before the tunnel is ready for traffic in late 2013, including paving of the roadway inside and outside of the tunnel, completion of the portal arch on the tunnel's eastern end, as well as the installation, configuration and integration of electrical, drainage and ventilation systems. Crews will also construct a permanent sound wall in Oakland measuring 2.5 meters (eight feet) high and 161 meters (528 feet) long.
For more info: see the Fall Project Update.
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