Amgen Incorporated, one of the world's largest biotechnology firms, recently developed a new research center on the Elliot Bay waterfront of Seattle, Washington. As part of the research center, a pedestrian bridge was built to connect the campus with a major transportation corridor. The owner's goal for the new pedestrian bridge was to create a signature gateway to Amgen's campus. The pedestrian bridge is a three-arch structure that depicts a three-dimensional helix. The overall shape of the bridge both reflects the helical DNA that connects all life and references the vital research under way at Amgen. The arches create the outline of the basic DNA helix, and the deck support and roof trusses complete the remaining components of the helix. The abstract double helix provided many design and construction challenges. The slim profile, large enclosed areas, and suspended deck meant wind and pedestrian vibration would be critical design considerations. The unique shape made it difficult to apply the standard building or bridge design codes. The contractor was faced with erecting this twisting structure over active railroad tracks while meeting tight geometric specifications. The bridge stands today as a testimony to the owner's vision, teamwork, innovation in bridge design, and creative construction techniques. The bridge combines both form and function to show how an ordinary pedestrian bridge can become an extraordinary statement while serving its intended function. The project has won broad community support in the few months that it has been open.
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