The design of lifting lugs is critical to ensure the safe lifting and handling of heavy equipment, tanks, or structural components. Lifting lugs are subjected to significant stresses during hoisting operations, and the integrity of their weld connections is paramount. This Excel sheet simplifies the design of welds for lifting lugs, ensuring compliance with standard engineering practices and safety requirements.
What Is a Lifting Lug?
A lifting lug (also called a lifting eye or padeye) is a steel plate welded or bolted to a structure or piece of equipment to provide a attachment point for rigging during lifting operations. They are used extensively in the construction, petrochemical, offshore, and manufacturing industries. A properly designed lifting lug must resist the full dynamic load imposed by the lift, including any dynamic amplification factor (DAF) or sling angle effects.
Forces Acting on a Lifting Lug Weld
The weld connecting a lifting lug to the parent structure is subject to combined loading:
- Vertical shear — from the lifted weight
- Horizontal shear — from the sling angle (if not vertical)
- Bending moment — due to eccentricity between the load application point and the weld root
- Out-of-plane bending — for multi-directional lifts
The sling angle is a critical factor. As the sling angle from vertical increases, the in-plane force component increases significantly and the weld must be designed for the worst-case lift configuration.
What This Excel Sheet Covers
- Input: lifted load, DAF, sling angle, lug plate geometry, weld size and type
- Calculation of weld throat area and section modulus
- Combined stress check at the critical weld location
- Comparison against allowable weld shear stress
- Safety factor output for design verification
Download the Lifting Lug Weld Design Sheet
Proper weld design for lifting lugs is a safety-critical task that must comply with applicable lifting and structural codes. This sheet provides a systematic, code-consistent method that reduces design time and gives engineers confidence in their lifting attachment designs. Download the free Excel sheet below.
