Construction methods · Heavy lift, moving and accelerated construction

Bridge jacking and lifting

Lifting an existing or new deck on hydraulic jacks: to replace bearings, to raise a bridge for clearance, to correct settlement, or to lift a launched deck onto its bearings. Millimetres matter, and every jack must move together.

How bridges get built · Heavy lift, moving and accelerated construction · Bridge jacking and lifting

Also called: deck jacking, bridge raising, bearing jacking, synchronised lifting

How it is done

Design jacking points on the pier or on temporary brackets; check the deck for the new support conditions.
Install jacks with load cells and mechanical locks; lift in small steps with synchronised control, monitoring the deck for differential movement.
Do the work (bearing change, plinth raising), then lower in steps onto the new support.

Where it fits

Bearing replacement, clearance increases, ILM and slide landing, settlement correction.

Where it does not

Jacking without locks (hydraulic failure drops the deck); jacking a continuous deck at one pier without checking the others.

Plant, pace and money

PlantHydraulic jacks (50-1,000 t), synchronised pumps, load cells, locking rings, brackets.

ProductivityA pier in a day.

CostUSD 20,000-200,000 per pier.

Risks and controls

What goes wrong

Differential lift cracking the deck, jack slippage, bracket failure.

Quality assurance

Jacking procedure with limits per step, load and displacement logs, survey of the deck during the lift.

Examples

Bearing replacements on every ageing viaduct; raising of Sydney and Bayonne-type bridges for shipping clearance.