The cost of suspension bridges rises rapidly with increases in span. This is partly due to the need to provide torsional stiffness to prevent flutter in high winds. The. extra material required to do this does not increase the strength, but its weight means that thicker cables are required to support it. If the need for torsional stiffness could be reduced or eliminated, the cost of a bridge would be significantly reduced.

The report describes a bridge configuration in which flutter is entire1y eliminated without the use of a torsion box. Two bridges were built side by side with their decks connected by lightweight transverse beams at intervals along the span. The only aerodynamic instability is a static divergence whose critical wind speed can be increased to any value by spacing the decks further apart.