Stanley Pier reconstruction
Underwater welding, pile works and floating steel formwork for rebuilding a pier in open water, planned over 190 working days.
- Year
- 2005
- Location
- Stanley, Hong Kong Island
- Status
- Completed
- Category
- Underwater & marine
Rebuilding a pier over open water means working below the tide line. We planned the whole job around a set of reusable waterproof steel formworks that are floated into position, sunk around each pair of piles to form a watertight mould for the concrete.
Sequenced in five stages
- Day 30: underwater welding of I-beam ties between piles, removal of nine platform piles, a crane platform, and the first formworks at A7/F7 and A6/F6 with five cross beams. A7/F7 concreted.
- Day 60: five more platform piles removed and the platform partly rebuilt, formworks moved to A5/F5 and A4/F4, four precast beams installed, A6–A5 concreted.
- Day 90: formworks at A3/F3, four more precast beams, A4/F4 concreted.
- Day 120: the A4/F4 formwork modified for A2/F2, formworks at A1–A2, precast stair beams.
- Day 190: the last precast units at A1–A3, final concrete pours, formworks and pile ties removed, and the upper-deck working platform built.
Formwork designed to float
Each formwork unit was drawn with its own weight and buoyancy so it could be towed and placed without heavy lifting: the A3/F3 unit weighs 4.8 t with 28 t of buoyancy, A7/F7 7.5 t with 58.5 t, and the larger A5–A4 unit 14 t with 127 t. A temporary working platform was added in December 2005.
Drawings
