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| Eastern portal of the Broadway High Level/Kennedy Tunnel. (Courtesy of Lafayette Historical Society) |
Caldecott Tunnel Timeline:
BEFORE THE CALDECOTT THROUGH TODAY’S NEW
FOURTH BORE
As we all eagerly await the opening of the new Fourth Bore of the Caldecott Tunnel it’s of interest to look back and see what folks had to deal with before there was a Caldecott Tunnel. For years we’ve complained about the long lines of backed-up traffic approaching the tunnel, but prior to 1937 the only way of getting from Oakland or Orinda, or vise versa , was to either go all the way around via Richmond or use this rickety single bore tunnel ! (Thanks to Mercury News/Contra Costa Times and Lafayette Historical Society for photos/info)
The Broadway Tunnel, as it was called then was opened in 1903. It was located above where the current Caldecott Tunnel stands. The single bore was only wide enough for a single car so drivers had to take a good gander that the tunnel was
clear to proceed.
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| Western portal of the Broadway High Level/Kennedy Tunnel. (Courtesy of Lafayette Historical Society) |
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| Snow at the western portal of the Broadway High Level/Kennedy Tunnel. (Courtesy of Lafayette Historical Society) |
March 10, 1934 – A man points to dark spots in the ceiling of the old tunnel where timbers fell earlier in the day. They had weakened by years of water damage. (Oakland Tribune Photo)
March 12, 1934 – View from inside the Old Broadway Tunnel when it was closed for repairs after timbers fell. (Oakland Tribune Photo)
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| November 6, 1936 – Crews also worked on the west portal during after the cave-in to care for any injured workers. (Oakland Tribune Photo) Looks like about the Old Broadway Tunnel had had its day…
And the New Three Bore Caldecott Tunnel would open just one year later – and some today still remember it. Seventy five years later it’s still pumping out cars and BART, and now a Fourth Bore will finally ease some ofthe heaviest traffic in the nation |
Move ahead 75 Years… THE NEW CALDECOTT BORE
BOR-ING FACTS:
–Hwy 24 currently carries about 160,000 vehicles daily through the three existing tunnels. Traffic congestion is experienced in the peak and off-peak directions. The new fourth bore will relieve congestion in the noncommute direction by permanently dedicating two bores to westbound traffic and two to eastbound traffic.
– The new tunnel has sophisticated fire-life-safety systems .
– The VID cameras will monitor traffic patterns and alert an operator if there is a slowdown or accident. There are linear heat, carbon monoxide and nitrous oxide detectors to monitor fire and air quality.
– There are 17 emergency stations equipped with fire extinguishers, manual fire alarms and emergency phones. In the event of a fire, 19 bi-directional jet fans will be activated along with the ventilation system and can redirect air flow.
-The tunnel lining has been built with special fibers that shield the tunnel from heat to prevent a strong fire from damaging the tunnel structurally.
-Variable message signs at the portal and within the tunnel will display preprogrammed messages triggered automatically
Fourth Bore Timeline (in reverse order)
FALL 2013 – Finishing the Caldecott new fOURTH BORE.
Construction Activities Update: November 2013
Photo by Karl Nielsen, MTC
Testing of the Fourth Bore’s state-of-the-art tunnel systems is proceeding to ensure that incidents inside the tunnel, such as a car accident or fire, are detected and suppressed rapidly. Fire drills, including emergency responder preparedness exercises, are in progress the week of November 11th. For the tunnel to open, these drills must be completed successfully. Learn more about the tunnel’s life safety systems in the recent Fact Sheet(PDF).
Photo by John Huseby, Caltrans
In late September, Caltrans started testing the Variable Message Signs (VMS) in Bores #3 and #4. The signs will illuminate with pre-programmed messages in the event of an incident in the tunnel, from a stalled car or a lane closure to a more serious incident. The messages can also be tailored to the circumstances. The purpose of the signs is to provide important life-safety instructions to motorists in the two bores. The signs will only be illuminated if there is an issue in the tunnel.
The testing of the VMS is just one of many elements of the Fourth Bore’s Fire & Life Safety systems that are being thoroughly tested prior to the tunnel opening to traffic.
Shown: TOS (Traffic Operations System) interface in the Caldecott Tunnels’ new Operations and Maintenance Control (OMC) facility near the western portals.
In progress: the installation of state-of-the-art fire and safety systems in the Fourth Bore. These systems include state-of-the-art fire detection and suppression systems. When the Fourth Bore opens to traffic in late 2013, TOS and SCADA (Supervisory Control And Data Acquisition) systems will provide specially-trained operators with real-time information and management capabilities for the four tunnels’ traffic, fire detection, power supply, ventilation and lighting systems.
SUMMER 2013
The installation of the Fourth Bore’s state-of-the-art Fire and Life Safety Systems is underway. The tragic fire of 1982 in the Third Bore resulted in extensive revision to national tunnel fire safety standards, and the Fourth Bore is designed to meet these stringent requirements. Nineteen jet fans, which were installed earlier this summer, will remove smoke from the tunnel in the event of a fire. The jet fans will be triggered by fire alarms, carbon monoxide detectors, and nitrous oxide detectors located throughout the tunnel. All of the Fire and Life Safety systems will undergo extensive testing before the tunnel opens to traffic in late 2013. Learn more about these systems in the Spring 2013 Fact Sheet.
Clockwise from top left: Workers install one of 19 jet fans in the crown of Fourth Bore. Workers mount stainless steel panels along the length of the tunnel; designed primarily for aesthetic purposes, the panels will also will help create a “tunneling effect” to focus motorists’ attention on the road ahead. Workers dismantled an enormous temporary soundwall on the western side of the tunnel in Oakland; the wall has been replaced by a permanent berm and soundwall. All photos by Karl Nielsen, MTC.
SPRING/SUMMER 2013
A Project Update Fact Sheet is available for download. Click here to view – May 2013 (PDF, 541 KB)
SPRING 2013
Work on the final retaining walls continued, along with facade work at both portals, and preparation for roadway paving.
Clockwise from top left: Roadway paving, Crosspassage ventilation system, Final retaining wall, near east portal. All photos by Karl Nielsen, MTC.
WINTER 2012/2013
Finishing work, clockwise from top left: Support rods for the electrical system are custom fitted inside the tunnel. Crews put final touches on one of seven cross passages between bores #3 and #4. A worker completes a trench as part of the drainage system currently being installed. All photos by Karl Nielsen, MTC.
FALL 2012
A Project Update Document is available for download. Click here to view – September 2012 (PDF, 636 KB)
LATE SUMMER 2012
On August 8th, just two weeks shy of the second anniversary of the start of tunneling, primary excavation of the Fourth Bore tunnel was completed. Work continues on excavating the “invert,” which is a trench, filled with concrete and rebar, to compensate for groundswell on the East side of the Hills. The tunnel’s waterproof membrane, rebar cage, and final lining continue to be installed from West to East, and the final lining is approximately one-third complete.
SUMMER 2012
This gantry system is a frame that slides on a track to facilitate installation of the tunnel waterproofing and final lining.
SPRING 2012
As work progresses on the bench, or bottom portion of the tunnel, tunneling crews are beginning work on the waterproof membrane and final lining near the western portal.
The first step is to apply 7 mm of waterproofing membrane that is made of a polymer-based material over the top of the smoothed shotcrete that has already been applied throughout the length of the tunnel. For the final lining, the contractor will cast a wall of reinforced concrete by assembling a rebar cage, constructing formwork to contain the concrete and pouring the concrete through holes in the form and then plugging the holes when the wall space is filled.
The formwork will glide forward as work on the lining progresses.
WINTER 2011
Excavation of the top portion, or topheading, of the Fourth Bore was completed on November 29th, 2011. Crews are currently excavating the bottom portion, or bench, of the tunnel from the west side using the project’s excavator and from the east side with the roadheader. Click here for details on this progress.
As excavation on the west side proceeds crews will begin working on the waterproofing and concrete lining that must be in place before the final concrete is poured for the arch and roadway surface.
Work on the safety cross passages between bores four and three is ongoing. To date, crews have completed excavation of two of the seven cross passages.
Click here to view the construction photo gallery.
Click here to view the current activity archive.
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