The Sundial Bridge (also known as the Sundial Bridge at Turtle Bay) is a cantilever spar cable-stayed bridge for bicycles and pedestrians that spans the Sacramento River in Redding, California, United States and forms a large sundial. It was designed by Santiago Calatrava and completed in 2004. The bridge has become iconic for Redding.
The 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. It also forms the gateway to the Sacramento River Trail, a 35-mile-long trail completed in 2010 that extends along both sides of the river and connects the bridge to the Shasta Dam.
The Sundial Bridge is a cantilever spar cable-stayed bridge, similar to Calatrava's earlier design of the Puente del Alamillo in Seville, Spain (1992). This type of bridge does not balance the forces by using a symmetrical arrangement of cable forces on each side of its support tower; instead, it uses a cantilever tower, set at a 42-degree angle and loaded by cable stays on only one side. This design 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.
The bridge is 213 m in length and crosses the river without touching the water, a design criterion that helps protect the salmon spawning grounds beneath the bridge. The cable stays are not centered on the walkway but instead divide the bridge into a major and minor path.
The cable for the bridge totals 1325 meter and was made in England. The dial of the sundial and a small plaza beneath the support tower are decorated with broken white tile from Spain. The bridge's deck is surfaced with translucent structural glass from Quebec, which is illuminated from beneath and glows aquamarine at night. The steel support structure of the bridge was made in Vancouver, Washington and transported in about 12-meter sections by truck to Redding.
Plans for the Sundial Bridge began in the 1990s, when the city of Redding budgeted $3 million for a pedestrian bridge across the river. However, costs escalated after Calatrava's design was chosen in 1996, and the project became a controversial one within Redding, supported by a small group of doctors, lawyers, and other professionals but opposed by other residents who thought it would be too expensive and who favored a more "folksy" covered bridge design. The bridge was completed in 2004, three years later than originally planned, at a cost of $23.5 million, with funding from the Redding-based McConnell Foundation. The expense was justified on the basis that it would increase tourism in the Redding area, which also features Shasta Dam as another architectural marvel, and it has been successful in that goal.