Weeping Oak Bridge

The Brief "I like what you have done for me before. I need a bridge over the stream in my garden, but don't think bridge, think dramatic and sculptural."
Intended Use The function of this structure is twofold. Its main use is a dramatic feature in a woodland setting. But it must also be a structurally sound bridge suitable to cross a small stream with private foot traffic.
	Structure, Design Features and Species Incorporated. The structure is a 26-foot diameter arch made of 3 segments of selected curved oak log, one of which is a fork. Each piece is stripped of bark and sapwood and shaped to maximise the effect of one near semicircular tree. They are then finished by hand with an adze. The deck is suspended by hangers from the joints in the arch. The joints are joggled to help the hangers obscure the joints, thus helping the illusion that it is one tree. One of the design concepts is to make it clear that this is a functioning arch, strong enough to allow the deck to be suspended from it, and not a beam bridge with a purely decorative arch above it. To achieve this the deck planks are longitudinal and there is purposely no room to hide a significant beam under them. The central concept is that this just might be one tree that we have somehow turned into a bridge. The deck planks are individually curved to fit their part of the deck plan, which is like a concave lens. This plan shape is decorative but is defined by the needs of the structure. It is wide at the fork to include the fork feet and to hide the stainless DPC/locators; it narrows in the middle to allow the hangers to be nearly vertical. It widens again and surrounds the butt to allow users to exit either side of the tree itself, but also to allow the illusion that it might still be rooted in the ground. The handrails are cut from grown bends and have the same plan shape as the edges of the decking. The edge of the decking was also designed to allow the toe boards to bend and follow its curves. All timber components are unseasoned English Oak from sustainably managed woodland. Our particular working method, which often involves starting from the tree, makes the design and construction of this type of structure possible. All timber is isolated from the concrete abutments by stainless steel spacers. Sapwood has been excluded from structurally and visually important areas. We used a selection of our usual suppliers for this project. Mike Smith the forester, who spotted the fork that was a good match to our specification, was pivotal in our success.

© AOC 2001