Sundial Bridge at Turtle Bay

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Coordinates: 40°35′34.27″N, 122°22′39.46″W

Sundial Bridge
Sundial Bridge
Official name Sundial Bridge at Turtle Bay
Carries Bicycles and pedestrians
Crosses Sacramento River
Locale Redding, California
Design Cantilever spar cable-stayed bridge
Total length 700 ft (213 m)
Width 23 ft (7 m)
Clearance below 26 ft (8 m)
Opening date July 4, 2004

The Sundial Bridge is a cantilever spar cable-stayed bridge that spans the Sacramento River in Redding, California. It was designed by Santiago Calatrava and completed in 2004 at a cost of US$23,000,000.

Similar to his earlier (1992) design (the Puente del Alamillo in Seville, Spain), this subtype uniquely does not balance the forces by using a symmetrical arrangement of cable forces on each side of the tower; instead it uses an angled cantilever tower loaded by cable stays on only one side. This requires that the spar resist bending and torsional forces and that its foundation resists overturning. While this leads to a less structurally efficient structure, the architectural statement is dramatic.

This pedestrian bridge features a single 217 foot (66 metre) mast that serves as the gnomon of the world's largest sundial. Sundial Bridge's shadow is cast upon a large dial to the north of the bridge, though the shadow cast by the bridge is exactly accurate on only one day in a year - the summer solstice, June 21. The tip of the shadow moves at approximately one foot per minute so that the Earth's rotation about its axis can be seen with the naked eye.[1]

Sundial Bridge provides pedestrian access to the north and south areas of Turtle Bay Exploration Park, a complex containing environmental, art and history museums and the McConnell Arboretum and Gardens, and to the Sacramento River Trail.

The bridge's deck is surfaced with translucent structural glass, which is illuminated from beneath and glows aquamarine at night. Drift boats of fishermen are often seen passing beneath the bridge as they fish for salmon, steelhead and rainbow trout. In the distance, Shasta is barely visible. Sundial bridge is 700 feet (213 m) in length and crosses the river without touching the water. The cable stays are not centered on the walkway but instead divide the bridge into a major and minor path.

The bridge is the cover image of a general physics textbook by Serway and Jewett as demonstrating the bridge's resisting of wind and gravity.[1]


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  1. ^ a b Physics: For scientists and engineers with modern physics. Serway and Jewett, 7th Ed. Thomson, Brooks/Cole. 2007. Back cover.

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