Structural & Mechanical

Lifting Lug Capacity Calculator

Screen net-section, shear-out and bearing limit states for a simple plate lug, with explicit dynamic and load-sharing assumptions.

We cut a 20 mm plate lug for a two-tonne lift. Is the pin-hole region obviously inadequate?
High-consequence screeningUse this result to screen and frame the problem—not to approve regulated or high-consequence work.
Core formulae

Lifting lug screening reference

Design demand per lugF_lug = W × dynamic / n_lugs × sharing
Net-section capacityF_net = (b − d) t f / SF
Shear-out capacityF_so = 2 e t τ / SF
Bearing capacityF_b = d t σ_b / SF
Simple arrangement sketch

Single plate lug

Fnet sectionet
1

Lift and simple plate geometry

This is deliberately a narrow screening model, not a lifting-device design.

Results

Plate-lug screening

Static lifted weight19.61 kN
Design demand per lug18.39 kN
Net-section capacity191.3 kN
Shear-out capacity114.8 kN
Bearing capacity75 kN
Governing screening capacity75 kN

Bearing

Governing utilisation24.5 %
Edge ligament35 mm
The three simple plate checks are below the entered screening limits

This is not enough to approve a lift. The result only means these three simplified checks did not govern under the assumptions entered.

High-consequence area — formal lifting design may be required

Not checked: welds, pin bending, plate bending, out-of-plane loading, lug eccentricity, local contact, combined stresses, fatigue, sling hardware, proof testing, lift points on the parent equipment, centre of gravity or lift planning.

Scope

Generic stress-based screening of net section, two-plane shear-out and projected bearing only. It does not claim compliance with AS 4991 or any other lifting standard.

Job-file record

Save the calculation, not just the number.

Copy a permalink that reloads these inputs, or download a PDF record with inputs, visible results, assumptions, a sensitivity note, date and disclaimer.

Important boundary

A calculator can show the arithmetic. It cannot establish every requirement that applies.

Confirm the actual equipment, loading, materials, condition, jurisdiction, contractual requirements, standard edition and current project documentation before using the result for design, repair, testing or lifting decisions.

Ask an engineer about this calculation →