Fourth bore in Caldecott Tunnel is underway


Work on the Caldecott Tunnel's long-anticipated new fourth bore is in full swing. The shovels first hit the dirt two months ago, but you won't see any signs of an actual tunnel just yet. Caltrans senior bridge engineer Peter Stryker says right now it's all about preparing the site for excavation.

"The tunneling shouldn't start until mid-summer, in July. We still have to get the equipment in and everything like that. I mean, we've got a considerable amount of work here to get access to the mining operation," says Stryker.

On the east side, workers are drilling holes 60-80 feet deep. It is part of building retaining walls to keep the hillside intact when excavation does begin.

"Depending on whether you hit some hard material, it can take all day to drill one hole or it can take half a day to drill a hole. It really depends on what you hit when you get down there," says Stryker.

On the west side, a temporary sound wall is going in around what will be the heavy-equipment staging area and mining operation.

"The steel beams that are cast into the ground with timber panels and sound absorption material on both sides," says Stryker.

Once the tunnel is completed, the temporary sound wall will come down and a permanent, landscaped dirt berm and sound wall will go in.

ABC7 looked at a Caltrans simulation that shows what the finished east portal should look like and on the west side, providing two lanes of traffic going both directions 24/7, eliminating the chronic bottlenecks.

Most of the tunneling will be done by a piece of equipment called a road-header, like the one being used for the Devil's Slide tunnel. The Caldecott's road-header is being built in Germany and should arrive in June.

"Come this summer you'll see some really big machinery out here and that's going to be exciting. Stuff that dwarfs everything that is out here right now, so that's going to be really cool," says Jeffrey Weiss from Caltrans.

Target date for completion is 2013.

Copyright © 2023 KGO-TV. All Rights Reserved.