An integral flat arch bridge

This paper presents the design and construction of an integral bridge that provides road access over the River Nene in Northampton (UK), to the new university campus. The client's aspirations and planning requirements mandated retention of the existing landscape character while also creating an appropriate landmark. This resulted in an elegant 50 m span flat arch structure with only 3·6 m rise. The awarded tender design proposed an alternative steel–concrete composite solution that is integral with its abutments and includes stiffened counterfort walls. A comparison between several alternative articulations arrangements considered for the rigid frame structure is presented. Sensitivity-based analysis between geotechnical and structural models for the derivation of support stiffness and resulting global load distribution between deck and piled foundations relating specifically to the flat arch arrangement is also described. Finally, a discussion of construction sequence, tolerance considerations, and tempo...