Lined, Then Sealed, Then Delivered This Fall. The New Irvington Tunnel Reaches Another Milestone

Imagine an 8.5 foot in diameter steel pipe roughly the length of a tractor trailer. Now imagine gently placing it into a 14-foot tube the length of 1½ Golden Gate Bridges? Now weld each of them together from the inside of the installed pipe in less than two months.

Well, that is EXACTLY what we did. This week the New Irvington Tunnel contractor completed the installation of a total of 14,600 feet (2.7 miles) of the welded steel liner into the tunnel. The 50 foot segments were all installed from the Sunol Valley and transported with a customized pipe placer westward into the tunnel. This completes the steel lining for the entire 18,660 foot (3.5 miles) New Irvington Tunnel.

What’s next? More grouting! Our teams will mobilize in March to prepare the tunnel to place cellular grout into the space between the steel liner and the excavated tunnel. This will effectively backfill the space between the tunnel pipe and tunnel wall, sealing it off to prevent water from seeping into or out of the tunnel.

We plan to bring the New Irvington Tunnel into service this fall, when drinking water will officially be transmitted through the new tunnel. Final project completion of the New Irvington Tunnel Project – including above ground restoration - is expected in mid-2015.

The New Irvington Tunnel will provide a seismically designed connection for water supply for 2.6 million bay area customers. 

50 ft segments of steel liner being delivered
Photo credit: Robin Scheswohl

View of steel liner from inside of Alameda West Portal
Photo credit: Robin Scheswohl

Welding work taking place on steel liners
Photo credit: Robin Scheswohl

New Irvington Tunnel Challenge Continues!

Tunneling excavation continues east from Mission Boulevard with the use of controlled detonation at a rate of approximately 12 feet per day. A road header travels west from I-680 at a rate of approximately 15 feet per day. When will the two meet?

Your challenge is to figure out the day and time you think the tunneling workers will meet. Guess correctly and you could win a prize pack featuring gift certificates to local business and other goodies! The chart has squares corresponding to a date and timeframe in June or July, when the rendezvous could happen. Selections submitted by contestants are indicated by a star.

Information to Help You Choose

In June or July, miners excavating the new tunnel from the Irvington Portal in Fremont will meet miners tunneling west from the Vargas Shaft. When it happens this hole-through will mark the completion of the Irvington-Vargas tunnel segment.

The tunnel segment between Irvington Portal and Vargas Shaft is 4,500 feet long. As of May 7th, miners have tunneled 1,747 feet east from Irvington and 1,955 feet west from Vargas. Ground conditions dictate excavation. In ideal ground conditions, crews have tunneled up to 98 feet in a day. When ground conditions are poor they excavate less than 20 feet. Miners do not tunnel on Sundays.

How to Enter

1) Choose your top three squares and e-mail your choices to: fzamora@sfwater.org

2) Include the date and time you think the hole-through will take place. Squares will be assigned first come, first serve. Only one square is allowed per person

3) If the first choice is available then the square is assigned to that person. If the square is unavailable then the next available choice is assigned.

4) Submissions will be accepted until May 31. Please include your name, address, phone number and e-mail so we can contact you if you're successful!

Good luck!

New Irvington Tunnel Challenge!

Tunneling excavation continues east from Mission Boulevard with the use of controlled detonation at a rate of approximately 12 feet per day. A road header travels west from I-680 at a rate of approximately 15 feet per day. When will the two meet?

Your challenge is to figure out the day and time you think the tunneling workers will meet. Guess correctly and you could win a prize pack featuring gift certificates to local business and other goodies! The chart has 101 squares each corresponding to a date and timeframe in June when the rendezvous could happen. Selections for this week are indicated by an “X”.

How to Enter

1) Choose your top three squares and e-mail your choices to: fzamora@sfwater.org

2) Include the date and time you think the hole-through will take place.

3) Squares will be assigned first come, first serve. Only one square is allowed per person

4) If the first choice is available then the square is assigned to that person. If the square is unavailable then the next available choice is assigned.

5) Submissions will be accepted until May 31. Please include your name, address, phone number and e-mail so we can contact you if you're successful!

Information to Help You Choose

In June, miners excavating the new tunnel from the Irvington Portal in Fremont will meet miners tunneling west from the Vargas Shaft. When it happens this hole-through will mark the completion of the Irvington-Vargas tunnel segment. The tunnel segment between Irvington Portal and Vargas Shaft is 4,500 feet long. As of April 28th, miners have tunneled 1,702 feet east from Irvington and 1,890 feet west from Vargas. Ground conditions dictate excavation. In ideal ground conditions, crews have tunneled up to 98 feet in a day. When ground conditions are poor they excavate less than 20 feet. Miners do not tunnel on Sundays. Good Luck!

Road Header Rendezvous Challenge

A road header travels east from Mission Boulevard at rate of 45 feet per day. A second road header travels west from I-680 at a rate of 35 feet per day. When will the two road headers meet?

At some point, we’ve all scratched our heads and tried to figure out a math problem like that. Here at the SFPUC we won’t ask you to solve word problems. Instead, we invite you to be part of our Road Header Rendezvous Challenge.

In June, miners excavating the new tunnel from the Irvington Portal in Fremont will meet miners tunneling west from the Vargas Shaft. When it happens this hole-through will mark the completion of the Irvington-Vargas tunnel segment.

The chart above has 101 squares each corresponding to a date and timeframe in June when the rendezvous could happen. Your challenge is to figure out the day and time combination. Guess correctly and you could win a prize pack featuring gift certificates to local business and other goodies.

How to Enter
Choose your top three squares and e-mail your choices to fzamora@sfwater.org. Include the date and time you think the hole-through will take place. Squares will be assigned first come, first serve. Only one square is allowed per person.

For example, someone could submit the following:

1. June 19 between 6:01 AM and 12:00 PM
2. June 5 between 6:01 PM and 12:00 AM 
3. June 28 between 12:01 AM and 6:00 AM 

If the first choice is available then the square is assigned to that person. If the square is unavailable then the next available choice is assigned.

Submissions will be accepted until May 31. Please include your name, address, phone number and e-mail so we can contact you if you're successful!

Information to Help You Choose
The tunnel segment between Irvington Portal and Vargas Shaft is 4,500 feet long. As of April 24, miners have tunneled 1,657 feet east from Irvington and 1,810 feet west from Vargas. Ground conditions dictate excavation. In ideal ground conditions, crews have tunneled up to 98 feet in a day. When ground conditions are poor they excavate less than 20 feet. In the last month miners averaged 38 feet per day. Miners do not tunnel on Sundays.

We’ll update the tunnel’s progress every week at www.sfwater.org/nit. Good luck!

New Irvington Tunnel: A Year in Construction

The New Irvington Tunnel Project celebrated its first year of construction this past September. When complete the new tunnel will provide a seismically-designed connection between water supplies from the Sierra Nevada Mountains and the Alameda Watershed to Bay Area water distribution systems. Take a look at the important work taking place above and below ground:



Year One by Numbers:

1 Tunnel Shaft: At 115-feet deep and 41-feet diameter, the Vargas Shaft is the starting point for two of the tunnel headings.

2 Tunnel Portals: Carved into hillsides between Sunol and Fremont the Alameda West and Irvington Portals are access and exit points for the new tunnel.

3 Road Headers: Weighing in at a combined 127 tons these mechanical tunneling machines are grinding their way through 3.5 miles of rock.

76 Secant Piles: Drilled and poured 115-feet into the ground this interlocking circle of piles form the support for the Vargas Shaft.

3057 Feet to Date: Miners have excavated this total from 4 tunnel headings.

@ Work: Deeper at Vargas

The Vargas Shaft gets deeper everyday and will soon reach its final depth of 120 feet. Here are some photos of the shaft at various stages. Feel free to guess the depth of the shaft and post your answers in the comment section. Sign up for the blog and we will send you the answers.

February 22, 2011: __ feet

Both photos on March 4, 2011: ___ feet

March 10, 2011: __ feet