Scope of supply
- Eight form travellers, 220 t capacity
- Pier head brackets and stability towers
- Internal and external post-tensioning
- Geometry control and camber monitoring
Divisions involved
The problem
The river carries its full discharge for seven months of the year and the piers stand in the active channel. Everything above pier cap level had to be built from the deck, in a season that closes without warning. A single traveller pair per pier would not have finished the cantilevers before the water returned.
What we did
Four pairs of travellers were built and commissioned before the season opened so all four piers could cantilever simultaneously. Each traveller was designed around a 6-day cycle rather than the more usual 7, by moving the rebar cage assembly off the traveller and onto a deck-level jig. Geometry was controlled against a daily survey with temperature-corrected camber targets issued each morning.
What happened
All four cantilevers closed within the season. Measured closure error at the mid-span joints was within 14 mm vertically and 6 mm horizontally against a permitted 25 mm.
Measured outcome
- 160 m
- Main span
- 9.5 – 3.5 m
- Deck depth
- 8 (4 pairs)
- Travellers
- 6 days
- Segment cycle