Project Design
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Navigating the Geologic Puzzle The East Bay Hills are a jigsaw puzzle of different rock formations and faults, including three rock formations and four inactive faults along the Caldecott Tunnel alignment. The varied geology of the project site poses a technical challenge for the tunnel engineers and designers and the new tunnel is designed to withstand up to a 1500 year seismic event. The new tunnel will be located to the north of the existing tunnels and have two 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. The new tunnel will be approximately 41 feet wide and 3,389 feet in length.  Other elements of the tunnel include seven emergency cross passages, a new two-story operations and maintenance building, construction of retaining walls and a noise barrier, pavement overlay at the State Route 24 /Caldecott Lane interchange, improvements to eastbound State Route 24, realignment of the westbound Fish Ranch Road on-ramp, and improvements to the eastbound Fish Ranch Road on-ramp. In addition to the tunnel, this project will also include improvements at the Kay Street overcrossing and realignment of westbound State Route 24 to the northbound State Route 13 connector. For more information, please visit the project schedule page. |
Did you know? The Caldecott Tunnel is located along a lifeline route of the State highway system. As a result, its design must meet stringent standards that allow the tunnel to re-open to emergency vehicles within 72 hours of a seismic event. While Caltrans typically designs to prevent collapse of a structure, the fourth bore was designed to maintain serviceability. |
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