Network arch bridge

Structure

The inclined hangers with multiple intersections make the network arch bridge act like a truss, with only axial compressible and tensile forces. Bending moments and shear forces are very small in network arches.

The hanger arrangement is what separates network tied arch structures from other types of tied arches, such as those with vertical hangers. It is defined by the number of hangers, hanger inclination and hanger distance. A radial hanger arrangement provides an efficient structure, as shown by Benjamin Brunn and Frank Schanack in 2003. In the radial hanger arrangement the distances between the upper hanger nodes and the angle between hangers and arch remain constant. In order to avoid too long hangers this angle may be increased towards the bridge ends.

History

The network arch idea was developed by the Norwegian engineer in the end of the 1950s.

Advantages

Because both the arch and the tie are mainly subject to axial forces, their cross sections can be very small. Usually, transverse bending in the deck is bigger than bending in longitudinal direction. Therefore, a concrete deck that spans between the arches is a good solution for bridges with arch distances that are not too large. The concrete deck has longitudinal prestressing tendons in the arch planes.

Difference to Nielsen-Lohse-Bridges

• http://www.network-arch.com (Information on network arch bridges)
• http://home.uia.no/pert/ (Information on network arch bridges by Per Tveit)
• http://www.pineapplestudios.com/IWAYSite (Information on the construction of Providence River Bridge)

References

1. Brunn B., Schanack F., Steimann U., (2004) “Network arches for railway bridges”, Arch Bridges IV, Advances in Assessment, Structural Design and Construction, P. Roca y C. Molins (Eds.), {{ISBN. 84-95999-63-3, pp. 671-680, Barcelona, Spanien