Ealing Bridge

The Ealing Bridge made entirely of timber except for the tie bars and carriage beam end bearing plates, spans 18 metres across the Grand Union Canal at Northolt. It connects a housing estate to a green lung creating a valuable local amenity. It is a tied 3 pin arch, though initially designed to be built as a simple 3 pin arch, we introduced the tie bars when a late request was made by Ealing Borough Council Landscape Department to reduce the gradient (rise to span ratio) in order to achieve a 1:12 allowing disabled access over the bridge. The tie rods were later removed, as after a while, they went slack indicating that the abutments were more than able to take thrust at the abutments of the main carriage beams.

The bridge was lifted into position as an entire structure excepting the decking boards and balustrade, thus forming its own scaffold to complete the remainder of the works. The carriage beams were cut from single large section of boxed heart Oak measuring 250mm wide x 600mm deep and curved and tapered to form a graceful sweep.

This pedestrian’s eye view of the structure gives a feel for what a pleasing experience it is to walk across this large timber structure. It was a challenging undertaking for all concerned and is we believe a rare example of a large single span public access timber bridge in the UK. The decision to build in timber was to some extent controversial as there were concerns over the safety of the structure with regards to fire. As it turned out the bridge was set alight during the Tottenham riots of 2011, when a local person walked onto the crown of the bridge with a can of petrol and set the structure alight. Oak being a dense heavy timber burnt slowly giving the fire brigade time to extinguish the fire before too much damage was done. Working with our engineer The Green Oak Carpentry Company scarfed new ends to the main carriage beams and central posts, also replacing the remainder of the charred members, thus leaving the structure almost as good as new. Had this been a steel structure it is doubtful that it could have been salvaged in this way, given that steel softens and buckles when heated.

Detailed fabrication drawing show the careful thought that has gone into the design of this exceptional structure. Note that the deck gradient is lower than the carriage beam gradient to assist in achieving disabled access compliance, thus keeping the span to rise ratio as great as possible.

Given the large span and builder tolerances for the casting of the concrete foundations, we made one end of the bridge bearing plate adjustable using steel shims. As it turned out the assembly went without a hitch and the structure installation was completed in under a week.