Walton Bridge – a new arch bridge over the River Thames, UK

Walton Bridge comprises a steel thrust arch with pad foundations supporting a steel-concrete composite ladder deck. The arch ribs have parabolic profile and varying hexagonal cross-section, tapering from springing points to crown, and span 96.1 m. The total rise of the arch is 14.77 m with a span to rise ratio of 6.5. The bridge deck is suspended from the arch by bar-type hangers. Continuous end spans carry the bridge deck between the arch and end abutments, which are full height reinforced concrete. This paper discusses the method of design employed, including the impact of construction methodology and environmental constraints, together with analysis of aerodynamic effects. It focuses on a number of innovations that were introduced and challenges that were resolved. Two key issues were:

• Arch design utilising plastic section properties with reductions to account for the continuously curved steel plating making up the arch ribs;

• Design and specification of bar-type arch hangers for brittle fracture and fatigue, noting that there was insufficient industry guidance on either subject.