511 Contra Costa

Now that the east and west sides of the Caldecott Tunnel meet, construction crews have started working on installing rails for a gantry system and waterproof membrane. Check out the newest construction photos below.

Above: Crews began installation of the rails for the gantry system and the waterproof membrane in early January 2012. The gantry system is a set of tracks and a frame that will enable the waterproofing and final lining installation equipment to slide from west to east as tunnel excavation is completed.

Above: Installation of the waterproofing membrane will be completed in sections followed by the concrete arch tunnel lining and roadway concrete.

And if you missed the Caldecott Tunnel Fourth Bore Breakthrough, here’s a neat time-lapse video:

For more official Caldecott Tunnel construction information, visit http://caldecott-tunnel.org

Diablo Magazine recently published an article, “Tunnel Vision”, on the Caldecott tunnel. Did you catch it?

Read more about the Caldecott project here.

Congratulations to Karen H. of San Francisco! She correctly answered what was significant about the Caldecott Tunnel “breakthrough” – completion of topheading excavation by construction crews – and won $10 to Peet’s.

That marks the end of our Caldecott Tunnel Trivia Contest. Thanks to all for participating! Click here to see a full list of questions, answers, and winners.

Photo credit: Karl Nielsen

Congratulations to Julie D. of Walnut Creek! She correctly answered how many vehicles travel through the Caldecott Tunnel every day – 160,000 – and won $10 to Peet’s.

The Fourth Bore Project recently celebrated a major milestone with the tunnel “breakthrough”. What does this significant milestone represent for the project?

On Tuesday, workers saw the light in the Caldecott tunnel. Still a lot more tunneling on the bench but see the progress!

Watch videos of the Caldecott Tunnel breakthrough on the SFGate Blog.

Congratulations to Thomas S., who answered Caldecott Trivia Question #3 correctly and won $10 to Peet’s Coffee & Tea!

Caldecott Tunnel workers keep on tunneling! Here’s the latest graphic and digging updates:

• Eastern side topheading: 2,529 feet
• West side topheading: 613 feet
• West side bench: 197 feet

Congratulations to Stephanie V., who answered Caldecott Trivia Question #2 correctly and won $10 to Peet’s Coffee & Tea!

If you entered but didn’t win, Question #3 is now out. Happy Internet sleuthing! Click here to view the newest Caldecott Tunnel Trivia Question.

It’s Caldecott Fourth Bore Trivia Time!

The Fourth Bore project is breaking new ground every day. Keep up by testing your Caldecott knowledge and you might learn something new. And use your Internet sleuthing skills, for Peet’s sake!

The Nitty Gritty Details

• New trivia questions will be posted bi-weekly
• One lucky winner will receive a $10 Peet’s Coffee gift card compliments of 511 Contra Costa (Winners will be randomly selected from all correct respondents)
• Answers can be found on the project website at www.caldecott-tunnel.org

Another question…

The Caldecott Fourth Bore Project is composed of four construction contracts. The project to build the Fourth Bore tunnel is by far the largest but several other contracts are included that improve traffic flow in the area. These include:

• Kay Street Project
• Route 24/Highway 13 Interchange Project­

Q. What is the 4th contract?

• A. Broadway Tunnel Project
• B. Landscaping Project
• C. Tunnel Road Project
• D. Caldecott Tunnel Third Bore

Last week’s winner

Last week, Roxanne R. answered our trivia question correctly and was randomly chosen to win $10 to Peet’s Coffee & Tea. Congratulations, Roxanne!

Last week’s question and answer to Trivia Quiz #1 was:

The topheading from both the east and the west is being excavated now,  and that work will be followed by the bench, or bottom portion.

Q: Why is the top section of the tunnel being excavated first?
A: By excavating the top section of the tunnel first the miners maintain better control of the surrounding rock, which allows more efficient tunneling.