Simulation of cars heading west through the east portal of the 4th bore to be added to the Caldecott Tunnel Simulation courtesy of CalTrans

"Fully funded and ready go" was the mantra of an enthusiastic team from the California Department of Transportation (CalTrans) as they outlined the plans for the Caldecott Tunnel Improvement Project-a.k.a. the Fourth Bore-at a community outreach meeting held in Orinda on December 10th. Construction of the two-lane bore on the north side of the Caldecott Tunnel is scheduled to get underway by mid-January and projected for completion by the winter of 2013-2014.
"It is a unique project in the state of California, because it is coming together through the partnership and funding of several agencies," stated Amy Worth, an Orinda City Council member and a representative to the Contra Costa County Transit Authority. The $420 million fourth bore project will be funded through regional, state, and federal funding sources, including $123 million in Contra Costa County Measure J monies and $192 million from the federal stimulus package. "This project is the largest recipient of American Recovery and Reinvestment Act funds in the nation," stated CalTrans Project Manager Cristina Ferraz, adding that approximately 7,000 to 8,000 jobs will be generated by the project.
The addition of the fourth bore will relieve traffic congestion in the non-peak direction, eliminate the daily lane-direction reversals of the center bore, improve travel times, and increase safety and evacuation access in the case of an emergency. "On top of all that, the fourth bore will look very nice," stated Ferraz, who also assured community members that they would continue to receive clear radio and cell phone transmissions (hands-free device required, of course) as they travel through the brightly lit tunnel.
A Little History. Work on the Highway 24 connector between the Contra Costa and Alameda counties, through the Berkeley hills, started almost 140 years ago in the 1870's. Public funding for infrastructure was as hard to come by then as it can sometimes be today, and it took until 1903 before a timber tunnel passageway opened. The design for two bores placed on the southern side of the hill began twenty years later, and bores one and two opened in 1937 followed by the addition of bore number three on the north side of the hill in 1964. Almost a half-century later, the construction of a fourth bore will get underway.
How's it Done? The 3,389 foot-long tunnel will have 12-foot lanes, a 10-foot north shoulder, a two-foot south shoulder, a two-foot north emergency walkway, and a three-foot south emergency walkway. Utilizing a sequential excavation method, crews working from both the east and west sides of the hill will be excavating and stabilizing small segments of the tunnel progressing about one to two meters a day. Situated less than half a mile from the Hayward fault, the project has been designed to withstand a significant seismic event and will include seven cross passages to the adjacent tunnel.
"We will be closing bore three quite a bit during excavation," stated a CalTrans construction manager, however he explained that these closures would be conducted between 10 p.m. and 4 a.m. "Traffic impact on a daily basis will be relatively small," he said adding, "there will never be a full freeway closure during the project."
The Noise and Dust! There will be no blasting at night, and noise levels will be monitored throughout the project to ensure that the noise level is kept down, according to CalTrans. To control the dust and dirt, stockpiles of excavated material will be wet down, trucks hauling debris will be covered, truck wheels will be washed, and local streets swept.
CalTrans will conduct further community outreach meetings throughout the project as needed. A fourth bore website will be up and running by mid-January. Until then information about the project can be accessed at the Cal Trans website, http://www.dot.ca.gov/dist4/
caldecott/index.html.

Copyright Lamorinda Weekly, Moraga CA