Start from the real load
Take the heaviest item you will lift, then add the weight of the sling, magnet or grab. That is your gross load.
Apply dynamic factors
- Hoisting: lifting from rest adds ~1.1–1.3× (more for sudden snatch).
- Traversing: acceleration adds lateral force.
- Wind: outdoor gantry and RTG need wind load in the calc.
Add duty and future growth
Pick the duty group (A3–A8) by daily cycles and severity. Always size for the largest load you may handle in 10 years, not just today. Underspec and you risk the structure; overspec and you waste steel and energy.
Let Tongyu size it
Send us the item weight, lift height, span and duty. We return a sized plan with the right overhead or double girder — request a quote →