Lifting Lug Design

The calculator does not assume one: it computes every limit state, shows each utilisation, and names the highest in each code and overall. Two effects are worth knowing. Pin bearing depends only on the plate thickness, the pin diameter and the yield strength, so a thicker plate helps it and a wider one does not. And once the sling is inclined, the moment of its horizontal component about the base acts on the base section and the weld, and either can then govern.

No. The sling is assumed to lie in the plane of the plate, at the entered angle from vertical. The pin-hole checks take the full sling force; the base section and the weld take its vertical and horizontal components and the in-plane moment of the horizontal component about the base. A sling out of the plane of the plate bends the base about its weak axis, and that is not computed. Nor are local bending above the hole, cheek plates, the shackle and pin, or the lifted object.

ASME BTH-1-2020 cl. 3-1.3.1: N_d is 2.00 for Design Category A, 3.00 for Category B and 6.00 for Category C. Category A is predictable, controlled service; Category B is general service where the loads are not precisely defined; Category C is selected where the specification for the lift requires it. Fracture and connection limit states carry a further factor of 1.20. Choosing the category is a judgement about the lift, not about the plate.

On fracture and connection limit states: tension through the hole (3-45), single-plane fracture (3-49), double-plane shear (3-50) and the weld (3-55) are divided by 1.20 N_d, once. The base-section stress (3-1) and pin bearing: Eq. (3-53), or Eq. (3-54) for a connection that rotates under load at Service Class 1 or higher: are divided by N_d. The factor column of the checks table prints the divisor used on every line.

Because 360-16 is the edition the AISC checks implement. AISC 360-22 adds a clearance-dependent factor C_r to Eq. D5-2, and this calculator does not apply it, so the AISC column is labelled AISC 360-16 (ASD). In the BTH-1 checks, pin-to-hole clearance is penalised through C_r in Eqs. (3-45) and (3-49) and through the tear-out angle φ in Eq. (3-50), and those are applied.