Calatrava's Turtle Bay Sundial Bridge

What price beauty? According to Metropolis Magazine (Buying The Bridge, November 2004) the final cost for Santiago Calatrava's footbridge over the Sacramento River for the town of Redding, California was $23.5 million, far above the original $3 to $5 million budgeted for the project.

The bridge connects the city's Turtle Bay Museum with parkland on the river's opposite shore. The bridge's 700 foot long by 23 foot wide deck is supported by a sculptural, inclined steel pylon and 14 cable stays. The steel pylon was fabricated in Vancouver, Washington and shipped to the site in sections weighing 30 to 40 tons each. In order to minimize the bridge's environmental impact, it avoids setting foot in the river or even casting shadows into the river's sensitive salmon spawning grounds. Yet the pylon does function as a sun dial, casting its shadow onto the large plaza formed at its base.

According to Modern Steel Construction's Sun Sculpture (October 2004), the project was not just a financial challenge for the client, but also a constructional challenge. The project required approximately 500 construction drawings to be completed by the construction team based on preliminary design drawings provided by Calatrava. This documentation work included:

• 3-d modeling of the original design
• Sophisticated mathematical adjustment of the 3-d model providing cambering to counteract dead and live loads on the structure
• Development of detailed descriptions of each of more than 1200 steel plates, including different angle cuts on each edge in preparation for full-penetration welding to adjacent plates
• Preparation of several scale models and an animation to assist with visualization of the bridge and its construction sequencing

Complicating this work was the fact that the pylon is a double-walled structure, with the non-parallel inner and outer walls. Detailing took almost 2 years to complete.