Lifting and Rigging Plans for Heavy Steel Fabrication: What the Shop Should Document

Lifting and Rigging Plans for Heavy Steel Fabrication: What the Shop Should Document

A fabricated girder or heavy vessel section is most at risk when it is lifted, turned or moved between work stations. The steel itself is rarely the problem. The problem is an unplanned lift: a lifting point welded in the wrong place, a sling angle nobody calculated, or a load that was guessed rather than weighed. A written lifting plan removes most of that risk. It also gives a buyer something concrete to review before any heavy member moves.

What a lifting plan should state

A lifting plan for a shop lift does not need to be long, but it needs to answer the same questions every time:

• The weight of the member, from the drawing or a weighing record, with the basis of that figure stated
• The centre of gravity, marked on the drawing or calculated, and the lifting points placed around it
• The crane or hoist used, its rated capacity at the working radius, and the rigging it will use
• The sling type, size and configuration, with the included angle between legs
• The route the load will take, including any turning or set-down positions
• The person responsible for the lift and the person who signs the plan

Lifting points are part of the design

Lifting points should be shown on the fabrication drawing, not added on the shop floor. Each point needs a rated capacity, a welding procedure, and an inspection record. Where a point is welded to a primary member, the weld and the member plate at that location must be checked against the design load for the lift, which is usually higher than the in-service load because of dynamic effects and sling angles.

A common error is to treat a lifting point like any other attachment. It is a load-bearing detail and should be inspected like one, including surface testing of its welds where the quality plan requires it.

Sling angles change the load

The load in each sling rises as the angle between the legs widens. A two-leg sling that carries a fair share of the weight at a narrow angle can be overloaded at a wider one. The lifting plan should show the angle used, and the rigging should be selected from the rated capacities at that angle, not from the single-leg rating printed on the sling.

Spreader beams or lifting beams reduce the angle problem and keep the sling forces vertical. They are often the better choice for long girders, where the lifting points are far apart.

Check the weight before you lift

Weights on paper are often wrong. Plate sizes change, fittings are added late, and a coated member weighs more than the uncoated figure. For a critical lift, weigh the member, or calculate it from the as-built material list and record the difference. Where the calculated and weighed figures differ noticeably, stop and check the material list before the lift proceeds.

Practical checks before and during the lift

• Inspect slings, shackles and hooks for damage and confirm their current test or inspection status.
• Clear the route and the set-down area, and confirm that no one is under the load.
• Use tag lines to control rotation on long members.
• Lift a few centimetres first and check the load is level and the rigging is seating correctly before lifting further.
• Keep the lift within the crane's rated capacity at the actual radius, including the weight of the rigging.

What a buyer can ask for

For a heavy or long member, ask the fabricator to confirm the lifting points on the drawing, the weight basis, and the lifting plan reference for the job. This is a short document, and it tells you early whether the shop has planned the moves that the member will need before dispatch.

For how a heavy member moves from the shop to the site, see the notes on long steel girder transport and dispatch planning. For the facilities used for heavy handling, see the infrastructure page.