Construction methods · Cable-supported and arch bridges

Cable-stayed cantilever erection

The deck of a cable-stayed bridge is built outward from each pylon as a cantilever, each new segment (cast in a traveller or lifted as steel or precast) supported by the stay installed right behind it. The stays are the falsework; the cantilever grows 8-15 m per week from each pylon until closure at midspan and at the side-span piers.

How bridges get built · Cable-supported and arch bridges · Cable-stayed cantilever erection

Also called: stayed cantilever, cable-stayed deck erection, segment and stay cycle

segment, then the stay behind it; both sides in balancethe stays are the falseworkCable-stayed cantilever erection
Concept diagram (TheBridgeEng)

How it is done

  1. Build the pylon and the pier table; install the first stays to a short starter section on temporary supports.
  2. Cycle: erect a segment (traveller pour, steel lift from a barge with a deck crane, or precast segment), install and tension the corresponding stay pair, survey, adjust the next segment's geometry.
  3. Balance the side and main span cantilevers; tie the side span down at the anchor pier; use temporary stays or counterweights where the geometry is asymmetric.
  4. Close at midspan, re-tension the stays to the final force distribution, install the final surfacing and set the stays' anchorage protection.

Where it fits

  • Spans 200-1,100 m over navigable water, valleys and estuaries; steel, composite or concrete decks; anywhere the deck cannot be supported from below.

Where it does not

  • Sites where a single pylon cannot be balanced by a side span or anchor pier (the game rejects asymmetric layouts without room for side spans), very high wind without stability studies of the cantilever.

Plant, pace and money

PlantForm travellers or deck cranes (200-400 t), barges, stay installation equipment, stressing jacks, survey with GNSS and total stations.
ProductivityOne segment and stay pair per 5-10 days per cantilever; a 400 m main span in 8-14 months after the pylons.
CostDeck and stays USD 4,000-8,000 per m2 of main span; the game's cable-stayed rates.

Risks and controls

What goes wrong

  • Cantilever instability in wind or under an unbalanced load, stay force errors accumulating, geometry not closing, traveller or crane anchorage failure, vortex-induced vibration of stays before dampers.

Quality assurance

Stage-by-stage analysis with a construction control programme, stay force measurement by lift-off or vibration, survey after every segment with temperature correction, closure at the planned temperature.

Examples

Russky (1,104 m), Sutong (1,088 m), Stonecutters, Incheon (800 m), Millau's stayed spans; the game's pylons and stays follow this sequence in the animation.

In the bridge game

What Bridge Master applies when you pick it

Deck types: Cable-stayed, Extradosed, Orthotropic steel box, PSC box, balanced cantilever. Spans 200-800 m, up to 1100 m.

  • +30: The way cable-stayed bridges are built.
  • -10: Temporary tie-downs and wind tunnel tests of construction stages.

Try it in the game →

Related methods

Stay cable installation and tensioningPylon construction: concrete, anchorage zones and geometryBalanced cantilever, cast in place (form travellers)Cantilever erection of steel (derrick and lifting frames)Extradosed bridge construction

Further reading

Gimsing and Georgakis · PTI DC45.1 · fib Bulletin 30 Acceptance of stay cable systems

Stay cable installation and tensioning →