ABSTRACT
In the present practice the pure box girder bridge is widely used for spans up to 150–200 m. For spans above 200 m the box girder is still applied but then in combination with an additional cable support, as it is found in cable-stayed and suspension bridges.
In the traditional cable supported bridges the cable system is generally arranged to give mainly vertical support so that the lateral (wind) load has to be carried primarily (and often exclusively) by the girder in transverse bending. Therefore, to achieve sufficient lateral stability the span-to-width ratio has to be restricted.
For bridges with long spans and relatively narrow roadways it might prove advantageous to apply a spatial cable system that render not only vertical but also lateral support to the girder. Thereby, the limitation of the span–to–width ratio can be omitted.
