Superstructure Type | Bore 4 is 41.25 feet wide and has two 12-ft lanes for west-bound traffic on Highway 24, a 10-ft north shoulder, a 2-ft north emergency walkway, a 2-ft south shoulder, and a 3-ft south emergency walkway. Bore 4 is connected to Bore 3 by 7 cross-passages which serve as emergency exits. |
Substructure Type | The horseshoe-shaped tunnel is 50 feet wide and 32 feet high. |
Foundation Type | Bore 4 uses a double lining system consisting of an initial support system and a cast-in-place reinforced concrete final lining. A waterproof membrane was installed between the initial support and the final lining. |
Remarks | Bore 4 of Caldecott Tunnel opened to traffic on November 16, 2013. It was instrumented during construction under the interagency agreement between Caltrans and DOC. Bore 3 of Caldecott Tunnel (south of Bore 4; built in early 1960s) was instrumented in 1979 (CSMIP Sta. 58359). |