Sundial Bridge at Turtle Bay - Design

Design

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 700 feet (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 4,342 feet 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 40-foot sections by truck to Redding.