How bridges get built · Finishing, articulation and maintenance · Deck replacement and widening
Also called: redecking, deck rehabilitation, bridge widening
How it is done
- Staged: close half the width, hydro-demolish the slab from the girders, replace the shear connectors, cast the new slab, switch traffic, repeat.
- Panel replacement: remove slab sections at night, set full-depth precast panels with grouted pockets, reopen by morning.
- Widening: new foundations and piers or extended caps, new girders, new slab with a wet joint to the old, matching camber.
Where it fits
- Decks past 40-60 years in de-icing climates, bridges needing more lanes, girders still sound.
Where it does not
- Redecking girders with unknown condition; widening on piers that cannot take the extra load without strengthening.
Plant, pace and money
PlantHydro-demolition, cranes, precast panels, traffic management.
ProductivityStaged redecking a span per month; panels a span per week of nights.
CostUSD 400-900 per m2 of deck replaced.
Risks and controls
What goes wrong
- Girder damage during demolition, traffic loading on a half deck, differential settlement between old and new.
Quality assurance
Girder inspection after demolition, connector installation records, camber matching.
Examples
US interstate redecking programmes; Korean expressway widening from four to six lanes.
Related methods
Deck slabs on girders: cast-in-place, precast panels and stay-in-place formsPrefabricated bridge elements and systems (PBES)Bridge demolition and deconstruction
Further reading
FHWA Bridge Preservation Guide · PCI full-depth panel guidelines