Dorman Long Technology
Reference Project
Construction Equipment
Construction Engineering
Site Services
Infinity footbridge, UK

The Infinity Footbridge is the focal point for an urban regeneration scheme linking new development on the north shore of the River Tees in Stockton to an existing business park to the south.  This iconic structure is a 2-span tied arch, having its 120m main span structurally continuous with a 60m side span.  The steel arch is a single slender rib at each end widening and bifurcating within the spans to form a double rib over the river pier.  Thin precast concrete deck units are suspended from the arch and prestressed together longitudinally to form the arch ties. During completion of the bridge design DLT provided expert advice to the designer on erection methods and details for ease of fabrication and buildability.  DLT then provided full erection engineering services including erection scheme design, stage by stage erection analysis of the structure, aerodynamic response analysis, conceptual and detailed design of all temporary works and equipment, and production of method statements.  The erection method chosen utilised a tie cable linking the main span arch to the crown of the smaller arch to limit arch sway stresses during progressive erection of the deck units.  DLT also provided the strand jack equipment to install and adjust the tension in this tie.