A blog from the UK about bridges and bridge design
04 November 2011
Merseyside Bridges: 8. Dutton Horse Bridge
This is a short detour from Merseyside, however broadly that area might be defined. From Runcorn, the journey heads south-east towards Northwich. I stopped off at two bridges before returning north to the River Mersey. In broad outline, this route follows the course of the River Weaver, which is a tributary to the Mersey.
The first of the two structures is Dutton Horse Bridge. This twin-span timber bridge was completed in 1919 to a design by John Saner, who was the engineer responsible for many works along the River Weaver when its navigability was improved. The Dutton Horse Bridge spans alongside the river's main course, over a secondary channel used to help regulate the water level.
It is historically significant as one of the earliest surviving bridges to feature laminated timber. The laminated arches span about 31m, with two ribs slightly out of line with each other. Triangulated timber struts stiffen the arches and support the deck.
As with many timber structures, it's certainly an attractive bridge, and it's great to see it has survived so well. Two span bridges are reputed to suffer from the problem of the "unresolved duality", where the viewer lacks a primary visual focus and so feels discomfited. This is a phenomenon that has received support from at least one experimental study, where viewers consistently tended to prefer one or three-span bridges to those with two spans. At Dutton, the bridge is rarely seen in full elevation, as the footpath on the opposite side of the river seems not to be the main route. From any other angle, the number of spans is hardly relevant. Even in full elevation, I think it looks fine.
The black-and-white paint scheme is characteristic of several bridges along the Weaver, including the one I'll come to next.