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Lifting Equipment Design

LIFTING EQUIPMENT DESIGN

OPC designed a 6.5-tonne working load limit lifting beam for use with a crane manufacturer’s workshop gantry cranes. The project required a practical arrangement for handling loads with different lifting-point spacings and centres of gravity.
The design was developed for fabrication by Marine Repair B.V., with a complete engineering package covering structural verification, fabrication details and operating requirements.

Adjustable Picture-Frame Lugs

OPC proposed movable picture-frame lifting lugs to make the beam more versatile. These allow the lower attachment points to be repositioned along the beam to suit the item being lifted, giving the workshop greater flexibility than a fixed lifting-point arrangement.
The proposal was welcomed by the client and incorporated into the design. Two adjustable lower lugs, each rated at 5 tonnes, were provided alongside a fixed central lifting point rated at 6.5 tonnes. The overall beam working load limit remained 6.5 tonnes.
The movable lugs and their retaining stoppers were designed together, accounting for the forces arising from the permitted sling angles and beam inclination.

Structural Design and Load Distribution

The design was assessed in accordance with BS EN 13155:2020, covering the main beam, upper and lower lifting points, stoppers and welded connections. Calculations addressed bending, shear, deflection and local connection strength.

Adjustable lifting points also required clear limits on load distribution. OPC assessed the effects of an offset centre of gravity on the individual lug loads and crane reactions, then produced a dedicated drawing showing the allowable offsets for the illustrated lifting configurations.

This connected the structural calculations with the information needed by operators to select a suitable arrangement.

Fabrication and Operating Documentation

OPC supplied:

  • Basis of design and structural calculation report.
  • General arrangement, fabrication details and parts lists.
  • Welding details and equipment marking drawings.
  • Maximum allowable centre-of-gravity offset drawing.
  • Operation and maintenance manual, including inspection and proof-load testing requirements.

The package took the design from the initial lifting requirement through to fabrication and operating documentation, with the adjustable lug arrangement providing flexibility within clearly defined load limits.