A corduroy bridge — Dutch knuppelbrug — was originally a simple fixed bridge built from whole round logs. Later it became a bridge with one or two beams carrying small cross timbers or half-round logs as the walking surface. It is the most elementary timber bridge there is: no handrail, no plank deck, just round logs laid side by side.
Log paths across marshy ground are called by the same name, because they bridge waterlogged soil; in peat areas such a construction is also known as a peat causeway.
Where it is used
- Footpaths in nature reserves, across peat, marsh and wet hollows
- Informal and management tracks where a full bridge is neither practical nor needed
- Temporary crossings during forestry work
- Historic reconstructions of bog roads and old country tracks
The drawback
Round logs have one clear weakness: they get slippery fast. In shade, algae and moss grow within a season, and a corduroy bridge in the wet then becomes genuinely dangerous. An unfixed log also rolls or shifts underfoot.
Practical tips
- Make the walking surface grippy — flat-sawn tops, wire mesh over the logs or anti-slip strips remove most of the risk; bare round timber is the worst case
- Fix every log — screw or nail into the beams so nothing can roll
- Choose durable timber — ground contact and permanent wet call for durability class 1 or 2, or treated softwood
- Mind width and edge protection — for a public path a narrow log bridge without a handrail is not a safe solution; with a drop or deep water it needs a rail and a closed deck
- Inspect the bearings annually — where the beam meets the bank is where the timber rots first
Related terms
- Bridge
- Beam bridge
- Beam
- Timber
- Durability class
- Bank revetment
- Palisade
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