The engineering task
A large pressure vessel is transported horizontally, lifted by two cranes and rotated upright at site. Sling angles, support reactions and lever arms vary continuously during tailing. Test weight, internals and temporary attachments may shift the centre of gravity.
Lifting devices require more than a tensile check. Bearing, net section, welds, trunnion bending and local shell effects at the attachment must be verified at the governing intermediate angle. Appropriate dynamic and unequal-load factors must be included.
Required design data
- Vessel weights and centres of gravity for all erection states
- Lifting and tailing sequence with sling geometry
- Lug, trunnion and attachment geometry
- Dynamic, unequal-load and safety factors
Technical solution approach
Define erection states
Treat transport, horizontal lift, intermediate angles and vertical final position as separate load cases.
Resolve static forces
Calculate crane, sling and tailing reactions from weight, centre of gravity and geometry at each angle.
Size lifting devices
Check lugs and trunnions for tension, shear, bending, bearing and local stability.
Verify attachments
Assess welds and local shell effects using the actual load application.
Define the lifting instruction
Document allowable sling angles, crane loads, spreaders and temporary reinforcement for erection.
Expected deliverables
Suitable SOL ALPHA modules
The modules form a technically plausible toolchain. Their final selection and sequence will be confirmed during the later calculation against the applicable code and project conditions.