**A capping beam (in Dutch deksloof) is a horizontal beam placed on top of a row of piles or a sheet pile wall to tie the heads of the individual elements together, distribute loads and create a continuous bearing strip.** It is a familiar element in foundation and marine works such as quay walls, pile foundations and dolphins.
Function of a capping beam
The capping beam serves three main purposes:
- Tying — connecting individual piles or sheet piles into a single structure
- Spreading loads — converting point loads from the structure above into an even line load on the piles
- Providing a bearing surface — a flat seat for the quay wall, beam or floor slab that sits on top
Material
Capping beams are usually made of:
- Reinforced concrete — the most common, cast in situ or precast
- Steel — on steel sheet pile walls and dolphins, often a double channel or H-section
- Timber — on historic quay walls and when reusing timber piles
Application
Capping beams are found in:
- Quay walls and bank revetments — as a top finish over piles or sheet piles
- Pile foundations for buildings — as a beam to which the ground-floor slab or wall structure connects
- Dolphins — steel beams guiding ships along quays
- Temporary excavations — tying sheet piles so they retain earth together
Construction detail
For steel sheet pile walls, the capping beam is fixed with clamps or welded connections. For concrete piles, the piles are broken back slightly below the underside of the capping beam so that exposed reinforcement bonds with the freshly poured concrete.
Related terms
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