WHY STEEL BOX GIRDERS

The steel box girder bridge is gaining popularity among bridge designers. In 1980, the American Association of State Highway and Transportation Officials (AASHTO) Guide Specifications for Horizontally Curved Bridges permitted new bridge forms, including the single box cross section and widely spaced boxes with large overhangs. The new design code was recognition of the torsional resistance of steel boxes. This article highlights certain aspects of steel box girder bridges: aesthetics, functionality, serviceability, maintainability, constructability, and economy. Overall, steel box girders are more visually appealing and require less maintenance than I girders. Economically, several situations warrant the use of steel box girders, such as sharp horizontal curvature and launched construction.