Bay Area Tunneling

The San Francisco area is teaming with tunneling activities these days with a variety of projects encompassing water, transit and vehicular tunnels. In October alone, the New Irvington Tunnel for the San Francisco Public Utilities Commission was expected to achieve its final hole through, and the second of two TBMs for the Central Subway project for the San Francisco MTA was scheduled to begin boring. Additionally, the Caldecott Fourth Bore highway project for CalTrans is nearing completion and is on track for a 2013 opening.

Not going unnoticed, San Francisco has played host to both the North American Tunnel (NAT) Conference (2008) and the Rapid Excavation Tunneling Conference (RETC, 2011). In 2016, the International Tunneling Association’s World Tunnel Conference will visit San Francisco – its first North American appearance since 2010 in Vancouver.

What is interesting about the number of projects in the Bay Area is the variety of construction methods being used to build the tunnels. For the New Irvington Tunnel in the East Bay, crews are using conventional mining techniques to drive more than 18,000 ft of tunnel. Miners are standing sets and timbering behind roadheaders or using controlled detonations to advance the exposed face. At Caldecott, crews are also using roadheaders for excavation as they advance using the New Austrian Tunneling Method (NATM) to drive the 990-m long tunnel. Meanwhile, the Bay Tunnel (boring complete) and Central Subway projects used EPB TBMs for tunneling. Of note, the Bay Tunnel is the first bored tunnel built under San Francisco Bay (the BART trans-bay tunnel was built as an immersed tube).

As the water improvement projects wind down, SFPUC is undertaking its Sewer System Improvement Program (SSIP), a 20-year program to upgrade aging infrastructure and ensure reliability and efficiency. At the same time, continued build outs of the transit system will be needed to keep people moving efficiently in this densely populated region.

Colorado School of Mines
Since 2008, the Colorado School of Mines’ Office of Special Programs and Continuing Education has hosted the Tunneling Short Course. The course is an intensive three-day discussion of all things related to tunnel planning, design and construction and taught by internationally recognized experts in the field.

This year the course attracted more than 150 participants, the most in the history of the course. Highlights included the presentation of the Tunnel Achievement Award to Kiewit Construction for its role in the Portland East Side CSO project. Also, Louis Brais of Bouygues spoke on the Port of Miami Tunnel project during the annual banquet. The 2014 course will be held Sept. 15-17, again at the campus in Golden.

Course directors are Levent Ozdemir, Ozdemir Engineering and professor emeritus at CSM, and Tim Coss, Microtunneling Inc. The two also collaborate on the Ground Improvement Short Course (May 19-21, 2014) and the Microtunneling Short Course. Coincidently, the Microtunneling course marks its 20th anniversary when the course is held Feb. 11-13, 2014, also in Golden (in conjunction with a one-day Pilot Tube Microtunneling seminar on Feb. 10).

For information, please visit: www.csmspace.com.