Construction methods · Cast-in-place concrete decks

Form travellers and traveller anchorage

The moving formwork of balanced cantilever construction: a steel frame anchored to the last segment carries the soffit, web and top forms for the next one, then rolls forward. Its anchorage is the most safety-critical bolt group on the site.

How bridges get built · Cast-in-place concrete decks · Form travellers and traveller anchorage

Also called: cantilever form traveller, traveller, CFT

How it is done

Erect the traveller on the pier table with rails and anchorages bolted through the deck; load-test it before the first segment.
Cycle: release the rear anchorage, roll forward on the rails, re-anchor, set the forms to the survey, pour.
Overhead and underslung travellers exist; underslung types keep the deck top clear.

Where it fits

All cast-in-place balanced cantilever decks, extradosed bridges, cable-stayed concrete decks cast on travellers with stays supporting the tip.

Where it does not

Unchecked anchorages; overloading the traveller with stored materials.

Plant, pace and money

PlantTraveller pair per pier, hydraulics, rails and anchor bars.

ProductivityThe traveller cycle of 5-9 days sets the pace of the cantilever.

CostUSD 0.5-1.5 million per pair.

Risks and controls

What goes wrong

Anchorage failure and traveller drop, wind, rail misalignment during rolling.

Quality assurance

Load test, anchor bar tension checks every cycle, wind limits for rolling.

Examples

Every balanced cantilever in the game's construction animation.