Axiom Engineers

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Axiom Engineers: Transit - CALDECOTT BORE 4 TUNNEL


This Caltrans project involved construction of a two-lane bore and a new Operations Maintenance Center (OMC). The new bore allows for four lanes of west-bound traffic to Oakland on State Route 24 and is connected to the existing bore 3 via pedestrian cross passages.
The commissioned systems included all electrical distribution from both of the 12KV PG&E connections at the east and west substations to the 120V panel-boards.

This included all medium voltage switchgear, circuit breakers, motor control centers, emergency generators, transformers and the automatic switching logic between the two substations.
Other commissioned electrical systems included radio rebroadcast, fire protection, battery chargers, carbon monoxide and nitric oxide detection, tunnel lighting controls, traffic control systems, and call boxes.
Commissioned mechanical systems included tunnel ventilation, cross passage ventilation, OMC HVAC, fire protection standpipe and dry fire protection.
Additional commissioned services included integration testing of all systems and operator response.

The Caldecott Tunnel

The Caldecott Tunnel gets its name from Thomas E. Caldecott (1878–1951), mayor of Berkeley from 1930–1932, member of the Alameda County Board of Supervisors 1933-1945, and president of Joint Highway District 13, which built the first two bores.