The Caldecott Tunnel channels State Highway 24, a major highway that wends its way east from San Francisco Bay through the East Bay hills. A much-anticipated fourth bore opened this month, and traffic officials predict legendary back-ups at the entrance to the old tunnels will no longer plague motorists.
Despite Henry J. Kaiser’s fame as a major 20th Century industrialist, few today know that his construction firm was part of the consortium that helped build the original two tunnel bores.
In 1934, during the depths of the Great Depression, the Six Companies won a bid to build what was to be called the Broadway Low Level Tunnel (it would later be named for Alameda County Supervisor Thomas E. Caldecott).
The “Six” that were just finishing up Hoover Dam included Bay Area construction powerhouses Henry J. Kaiser Company and the Bechtel Corporation, plus four firms from Utah, Oregon, and Idaho.
Funding came from a variety of sources, including the Public Works Administration (not to be confused with the Works Progress Administration), a bond issued by California Highway District 13, and the State of California.
Boring of the tunnels began on September 1, 1934. But the geology of the Berkeley Hills is complex, and the engineering studies drastically failed to anticipate the difficulty of the project. As a report published by the Six Companies described:
“. . . nature's furtive facts were lurking within the hills to attack the theories of geologists, engineers and builder alike.” [i]
The obstacles included fractured shale, three distinct geological formations, earthquake faults, and unexpected water drainage. The report further noted:
“When new water sources were uncovered — usually from fifty to seventy-five feet apart — they were difficult to control, because water came in gushes apparently under pressure, and would run as much as five hundred or six hundred gallons per minute in each bore.”
All resulted in an engineering nightmare that increased costs, pushed deadlines, and worse. Two cave-ins took the lives of three workers.
As costs skyrocketed, the Six Companies tried to raise more money; when that failed, and litigation erupted, The Six Companies were severely fined and pulled out of the job, even though it was nearly finished.
But Henry J. Kaiser hated failure and felt his professional reputation was at stake. He offered the highway district his cooperation in maintaining the present work as well as assisting them in finding a suitable contractor to finish the project — which was no easy task.
On September 11, 1936, bids for completing the tunnel were put out and no one applied. The next month, with Kaiser's assistance, the contract was broken into eight units, and the work was finished by Pollock & Clifford (excavation and concrete), Clifford (grouting), Duprey (ceilings and roadway), Alta Electric (ventilation and carbon monoxide detectors), Morre (highway), and Berkeley Steel (steel structures).
The tunnels opened to traffic on December 12, 1937, and Henry J. Kaiser went on to tackle the Grand Coulee Dam, the wartime shipyards, and the health plan now known as Kaiser Permanente.
[i] The Story of the Broadway Low Level Tunnel, Six Companies,