An Introduction to the Optimal Network Arch

The optimal network arch is a steel arch bridge with a concrete tie. Some hangers cross each other at least twice. The optimal network arch makes good use of high strength steels. The bridge type normally saves between 50% to 75% of the steel compared to other steel bridges. The welds are short and the cost of fabrication is low. The partially prestressed concrete tie and the small steel surfaces give low maintenance costs. Nevertheless the cost of the steel per tonne will be moderate. For detailed information on network arches refer to Ref. [1] The Brandanger Bridge in Norway currently under design will have a span of 220 m (Fig. 10). Preliminary investigations indicate that approximately 40% of the cost can be saved by using a network arch instead of a beam bridge. For many equal spans above navigable water high strength concrete can be used in the arches of spans that are floated to the pillars.