Construction methods · Heavy lift, moving and accelerated construction

Strand jack lifting

Hydraulic jacks that climb bundles of strands lift thousands of tonnes slowly and precisely from a gantry on the structure above: deck sections of suspension bridges from barges, arches, and whole spans. Slow but unlimited in capacity and largely independent of crane vessels.

How bridges get built · Heavy lift, moving and accelerated construction · Strand jack lifting

Also called: heavy lifting by strand jacks, deck section lifting, lifting gantry

Strand jack lifting — concept diagram
Concept diagram (TheBridgeEng)

How it is done

  1. Mount lifting gantries with strand jacks on the completed structure (main cable, deck edge, temporary towers).
  2. Position the load on a barge below; connect the strands; lift at 5-20 m per hour with synchronised jacks; land and connect.
  3. Repeat; strand jacks also lower, slide and launch.

Where it fits

  • Suspension bridge deck erection, box girder sections for cable-stayed bridges, arch halves, spans up to 5,000 t or more.

Where it does not

  • Sites where a crane can do the lift faster; loads without a stable landing structure.

Plant, pace and money

PlantStrand jacks (50-800 t each), gantries, power packs, control system.
ProductivityOne section per day in a lifting campaign.
CostUSD 50,000-150,000 per section; system hire per campaign.

Risks and controls

What goes wrong

  • Strand jack synchronisation failure, gantry overload, barge drift under a partially lifted load.

Quality assurance

Lift procedure with load monitoring, strand inspection, synchronisation tests.

Examples

Every modern suspension bridge deck (Akashi, Great Belt, Xihoumen, Yi Sun-sin); Millau steel deck placement.

In the bridge game

What Bridge Master applies when you pick it

Deck types: Orthotropic steel box, Steel arch, Steel truss, Steel box girder, Cable-stayed, Suspension, Extradosed, Steel plate girder, Precast segmental box, Concrete arch, Network tied arch. Spans 100-300 m, up to 500 m.

  • +30: Central span over a shipping channel: float in and jack up.
  • -40: Needs barge draft.

Try it in the game →

Related methods

Suspension bridge erection: cables, hangers and deckFloating crane erectionLateral slide (slide-in bridge construction)

Further reading

Enerpac and VSL heavy lifting guides · DNV-ST-N001

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