CRAFTED EARTH, INC. | Steel Bridge Design
15433
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Steel Bridge Design

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About This Project

This canted arch bridge is designed for AASHTO loading and with minimal detailing could be built at a cost competitive with the more typical and mundane box girder bridges. The basic geometry of the bridge was conceived as a canted catenary arch. Two 80 ft tall catenary arches were modeled and splayed to accommodate the width of the bridge deck while sharing a single pin support.

Using the 3D modeling program Rhinoceros, in concert with the parametric scripting software Grasshopper, the curves of the bridge were divided evenly and lines drawn to corresponding points along the deck. In the design of a catenary arch, as opposed to a funicular arch, uniform division of the arch is essential to create uniform loading of the arch. In a funicular, the deck is uniformly divided,and vertical cables are strung to the arch. In this case, the arch determines the geometry, and we see a more dynamic, angular progression of cables strung to the deck.
Because the arches are canted outwards, their own weight keeping the top cables in tension, they provide stability to the structure with a fraction of the material of more conventional bridge types.