How Does a Crane Lift a Bridge Into Position?
Before the lift begins, the bridge or bridge section is assembled and its lifting points are confirmed. The crane is then configured around the known load, required radius and planned lift path, with the appropriate rigging selected for the operation.
During the lift, the structure is raised from its starting position, moved through the planned path and lowered onto its final bearings or supports.
Some bridge lifting operations can be completed using a single heavy crane. Others may require two or more cranes where the size, geometry or position of the structure means it needs to be supported at multiple points.
What Determines How a Bridge Is Lifted or Installed?
The installation method is selected around the bridge and the site. The largest available crane isn’t always the most suitable choice.
Bridge Weight, Dimensions and Centre of Gravity
Total lifted weight is an important factor, but it’s only part of crane selection.
The dimensions and shape of the bridge section, its centre of gravity and designed lifting points also affect the rigging arrangement and crane configuration.
These factors can determine whether the structure can be lifted in one piece or needs to be installed in smaller sections.
Lifting Radius and Crane Position
Crane capacity changes according to configuration and working radius. This means the distance between the crane and the bridge’s final position can be just as important as the load itself.
Crane positioning therefore needs to be considered alongside the required lift path and available setup space.
Access, Ground Conditions and Temporary Works
The crane needs suitable access and enough working space for its planned setup and operation.
Ainscough can provide relevant crane loading information within the agreed scope. Unless otherwise agreed within the project scope, the client or Temporary Works Engineer remains responsible for assessing the underlying ground bearing capacity and any required temporary works.
Roads, Railways, Rivers and Other Constraints
Bridge installation often takes place around live or restricted infrastructure. Road closures, rail possessions, overhead services, waterways, nearby structures and limited working areas can all affect the lifting method and programme.
These constraints may influence crane position, lift timing and the route the bridge section takes into place.
Weather and Programme Windows
Environmental conditions can affect whether a planned lift can proceed. Wind is particularly important, but there’s no single operating limit that applies to every bridge lift. Permissible conditions depend on the crane, its configuration and the project-specific lifting plan.
What Types of Cranes Are Used for Bridge Installation?
Different bridge projects require different crane arrangements.
Mobile Cranes
High-capacity mobile cranes can be used for prefabricated spans, bridge decks, beams and replacement works where suitable access and setup space are available.
Their configuration is selected around the required load, radius and site conditions.
Crawler Cranes
Crawler cranes may suit projects requiring higher lifting capacity, longer setup periods or repeated lifting from an established working area.
Tandem and Multi-Crane Lifts
Two or more cranes can be used where a bridge section needs support at multiple lifting points or where the required geometry cannot be achieved with one crane.
Tandem lifts are complex operations and require detailed planning, coordination and suitably competent personnel.
Are Bridges Always Installed With Cranes?
No. Launching, sliding and rotation techniques can provide alternatives where a conventional crane lift is unsuitable for the structure or site.
Other projects may use equipment such as self-propelled modular transporters, hydraulic systems or strand jacks where access, overhead restrictions, closure windows or the distance the structure needs to travel make a crane-only installation less suitable.
How Is a Bridge Lift Planned and Controlled?
Under the Lifting Operations and Lifting Equipment Regulations 1998 (LOLER), lifting operations must be properly planned by a competent person, appropriately supervised and carried out safely.
For bridge lifts, planning must account for confirmed load information, lifting points, crane configuration, radius, rigging, lift path, access, obstructions, environmental conditions and the wider site programme.
Risk Assessments and Method Statements perform different roles within this process. The Risk Assessment identifies hazards and establishes controls, while the Method Statement explains how the planned lift will be carried out.
Responsibility also depends on the hire arrangement. Under CPA Crane Hire, the customer is responsible for planning and managing the lifting operation.
Under a managed contract lift, Ainscough can assume the agreed responsibilities for planning, organising, supervising and carrying out the lift within the defined scope.
Bridge Installation Examples From Ainscough
Ainscough projects show how different bridge structures can require very different lifting methods.
M20 Footbridge Installation in Kent
For an M20 footbridge installation, the structure was supplied in two sections and two cranes were used during the operation before the bridge was positioned over the motorway.
The project demonstrates how the lifting arrangement can be adapted to the geometry of a prefabricated bridge structure and the constraints of a motorway installation.
Cockcrow Green Bridge Beam Installation
On the A3 project, Ainscough installed 22 bridge beams, rather than lifting the bridge as one complete structure.
Crane repositioning was required around the temporary works constraints, showing how bridge installation can be shaped by the site as much as the structure itself.
Crane-Assisted Assembly Before SPMT Positioning
For the Osmondthorpe Lane bridge project, Ainscough supplied crane support during assembly before the completed bridge structure was moved into position using an SPMT by the wider project team.
This illustrates how crane support can form one part of a larger installation method rather than being responsible for the final positioning itself.
Ainscough Supports Complex Bridge Lifting Projects
Ainscough supports road, rail and wider infrastructure projects with heavy crane capability and planned lifting support. Under a managed Contract Lift, our team can take responsibility for planning, organising, supervising and carrying out the lifting operation within the agreed scope.
To discuss a bridge lifting or installation project, discuss your lifting requirements with our team.
Frequently Asked Questions
Can A Whole Bridge Be Lifted Into Place?
Yes – a whole bridge can be lifted into position where its design, weight, lifting points, crane configuration and site conditions allow it. Other projects may require the structure to be installed as separate beams or pre-assembled sections instead.
How Long Does It Take To Lift A Bridge Into Position?
There’s no standard timeframe for bridge lifting. The duration depends on factors such as the bridge design, crane configuration, site constraints, access, rigging requirements and the available programme or closure window.
What Is A Tandem Crane Lift?
A tandem crane lift uses two cranes to lift and control the same structure. This approach may be required where a bridge section needs support at multiple points or where one crane cannot provide the necessary lifting geometry.
What Happens If A Bridge Is Too Heavy For One Crane?
Where one crane cannot complete the lift, the project may use multiple cranes, divide the bridge into smaller installation sections or select another positioning method. The approach depends on the structure, lifting points, site conditions and planned installation method.
How Are Bridges Installed Over Motorways Or Railway Lines?
Bridge installation over motorways or railway lines is planned around the available access and closure arrangements, such as road closures or rail possessions. The lifting method and programme must also account for surrounding infrastructure, restricted working areas and the available installation window.