Margaret Hunt Hill Bridge

Carrying six traffic lanes across the Trinity River corridor, the Margaret Hunt Hill Bridge is 368 meters (1206 feet) long, 36.7 meters (120 feet) wide and spans 184 meters (603 feet). The parabolic pylon (gleaming white steel arch) rises 136 meters (446 feet) above the banks of the Trinity River, not only serving as a new icon to the Dallas skyline, it also acts as the central support for the new bridge's deck via cable-stays enabling the use of a light, efficient deck system. Laced through that soaring arch are 58 cables, with diameters ranging from 165 to 127 millimeters (6.5 to 5 inches) and length ranging from 196 to 119 meters (642 to 390 feet). These extended in web-like sweeps to either side of the bridge. This array of cables effectively distributes the forces over the pylon and the symmetry of permanent loads helps maintain a slender, balanced arch pylon.

The arch pylon is a closed steel tube with internal diaphragms, stiffeners and anchor-ages for the cables. The central box girder acts as a spine and contributes greatly to the torsional rigidity of the system, which allows the cables to anchor along the centre-line of the bridge. The regularlyspaced ribs and the edge box girders help provide a frame which is stiff in-plane. The Margaret Hunt Hill Bridge is the first of a series of bridges designed by Santiago Calatrava to span across the Trinity River and at the same time, it is also Calatrava's first vehicular span in the United States. Work continues on the design of a new sister bridge further along the basin as part of the scheme to replace the existing Interstate Highway 30."