Lifting Lug Calculator

Lifting Lug Calculator — Report

Example project

Rev A

Generated 2026-04-18 00:37:35

Methodology: mechanics_raw

Units: SI

Inputs summary · SI (mm · kN · MPa)

Design load100.00 kN

Dynamic factor1.00

Lifting angle0°

Plate thickness20.0 mm

Plate width200.0 mm

Hole diameter52.0 mm

Pin diameter50.0 mm

Edge distance60.0 mm

Corrosion all.0.0 mm

F_{y}

355.0 MPa

F_{u}

490.0 MPa

Allow. tension213.0 MPa

Allow. shear123.0 MPa

Allow. bearing320.0 MPa

OffshoreNo

Weld leg8.0 mm

Weld length × count180.0 mm × 2

Weld allow.207.0 MPa

Schematic

Front elevation — plate, hole, pin, load at θ

Side view — fillet welds, leg s and throat a

Load decomposition — N, V, M on weld group

Figures are generated live from the inputs listed above. Geometry is drawn to scale within each viewBox; absolute sizes are illustrative only. Use the figures as a qualitative check that geometry and loading are not obviously wrong — they are not a CAD drawing.

Weld design — angle-aware fillet weld group

Lifting load $F$ at angle $θ$ (in-plane) is decomposed at the weld centroid into a normal component $N = F cos θ$ , a transverse shear $V = F sin θ$ , and an in-plane bending moment $M = V \cdot h$ , where $h$ is the pin-to-weld centroid distance.

Topology: Parallel side welds (two line welds along the lug sides).

Quantity	Symbol	Value
Lifting angle	$θ$	0.0°
Lever arm	$h$	150.0 mm
Applied load	$F$	100.00 kN
Normal component	$N = F cos θ$	100.00 kN
Transverse shear	$V = F sin θ$	0 N
Bending moment	$M = V \cdot h$	0.000 kN·m

Section property	Symbol	Value
Leg size	$s$	8.0 mm
Throat	$a = 0.707 s$	5.7 mm
Total weld length	$L_{tot}$	360.0 mm
Throat area	$A_{w} = a \cdot L_{tot}$	2036 mm²
Section modulus	$S_{w}$	61085 mm³

Throat stress	Formula	Value
Normal (⊥)	$σ_{⊥} = N / A_{w} + M / S_{w}$	49.11 MPa
Transverse shear	$τ_{⊥} = V / A_{w}$	0.00 MPa
Longitudinal shear	$τ_{∥}$	0.00 MPa
Equivalent (vM)	$σ_{eq} = σ_{⊥}^{2} + 3 (τ_{⊥}^{2} + τ_{∥}^{2})$	49.11 MPa
Resultant (\|R\|)	$∣ R ∣ = σ_{⊥}^{2} + τ_{⊥}^{2}$	49.11 MPa

Allow. shear (τ)207.0 MPa

Allow. tension (σ)358.0 MPa

F_{E X X}

483.0 MPa

Angle-aware stresses feed the Mechanics, ASME BTH-1, AISC 360-22 §J2.4, and EN 1993-1-8 §4.5.3 weld checks listed in the primary and cross-check tables. Out-of-plane effects remain out of scope — if present, FEA is recommended.

Governing summary

Governing checkDouble-plane shear-out (mechanics)

Utilisation0.598 (59.8%)

Overall statuspass

FEA recommendedNo

Primary checks — Mechanics of Materials

Check	Demand	Capacity	U	Status
Net-section tension (mechanics)	33.78 MPa	213.00 MPa	0.159	pass
Double-plane shear-out (mechanics)	73.53 MPa	123.00 MPa	0.598	pass
Pin bearing on lug (mechanics)	100.00 MPa	320.00 MPa	0.313	pass
Pin double shear (mechanics)	25.46 MPa	220.00 MPa	0.116	pass
Fillet weld throat resultant (mechanics)	49.11 MPa	207.00 MPa	0.237	pass
Fillet weld von Mises throat stress (mechanics)	49.11 MPa	358.00 MPa	0.137	pass
von Mises throat stress: $σ_{eq} = σ_{⊥}^{2} + 3 τ_{⊥}^{2}$ (longitudinal shear $τ_{∥} = 0$ for symmetric, in-plane loading).
Fillet weld strength — AISC 360-22 §J2.4	100.00 kN	442.56 kN	0.226	pass
Directional increase factor $(1 + 0.5 sin^{1.5} θ) = 1.500$ at $θ_{res} = 90. 0^{\circ}$ . Nominal throat strength $F_{n w} = 0.60 F_{E X X} (1 + 0.5 sin^{1.5} θ) = 434.7 MPa$ .

Cross-check (other frameworks)

Check	Demand	Capacity	U	Status
Net-section tension — BTH-1 §3-3.3.1	100.00 kN	220.09 kN	0.454	pass
Single-plane fracture — BTH-1 §3-3.3.2	100.00 kN	185.33 kN	0.540	pass
Double-plane shear-out — BTH-1 §3-3.3.3	100.00 kN	167.36 kN	0.598	pass
Pin bearing — BTH-1 §3-3.3.4	100.00 kN	147.92 kN	0.676	pass
Service Class 0 — static bearing coefficient $1.25$ applied (eq 3-53).
Fillet weld allowable — BTH-1 §3-3.4.3	49.11 MPa	80.50 MPa	0.610	pass
Clause allowable $F_{v} = \frac{0.60 F _{E X X}}{1.20 N _{d}} = 80.5 MPa$ ; compared to the von Mises throat equivalent $σ_{eq}$ .
Pin-plate geometry — EC3 §3.13.1	0.695	1.000	0.695	pass
Pin shear — EC3 §3.13.2	100.00 kN	1507.96 kN	0.066	pass
Two shear planes assumed (single lug in clevis).
Plate bearing — EC3 §3.13.2	100.00 kN	532.50 kN	0.188	pass
Pin bending — EC3 §3.13.2	0.05 kN·m	11.78 kN·m	0.004	pass
Moment from EN 1993-1-8 §3.13.2 Figure 3.11: $M_{Ed} = \frac{F _{Ed}}{8} (b + 4 c - 2 a)$ .
Pin combined shear + bending — EC3 §3.13.2	0.004	1.000	0.004	pass
Two shear planes assumed (single lug in clevis), matching the pin-shear check.
Fillet weld — EN 1993-1-8 §4.5.3.2 directional method	49.11 MPa	435.56 MPa	0.139	pass
Criterion (a) combined: $σ_{eq} = 49.1 MPa \leq \frac{f _{u}}{β _{w} γ _{M 2}} = 435.6 MPa$ → $u_{a} = 0.113$ . Criterion (b) normal: $σ_{⊥} = 49.1 MPa \leq \frac{0.9 f _{u}}{γ _{M 2}} = 352.8 MPa$ → $u_{b} = 0.139$ . Governing criterion: normal (b).
Fillet weld — EN 1993-1-8 §4.5.3.3 simplified method	277.78 N/mm	1422.30 N/mm	0.195	pass
Design throat shear $f_{v w, d} = \frac{f _{u} / 3}{β _{w} γ _{M 2}} = 251.5 MPa$ . Resistance per unit length $F_{w, R d} = f_{v w, d} \cdot a = 1422.3 N/mm$ ; demand $F_{w, E d} = 277.8 N/mm$ .
Dynamic amplification factor — DNV-ST-N001 §16	1.150×	—	—	info
Category default $DAF = 1.15$ selected automatically. Confirm against the project-specific clause before use.
Skew-load factor — DNV-ST-N001 §16	1.100×	—	—	info
Single-lug padeye default $SKL = 1.10$ . Multi-sling redistribution is out of scope for v1.

Assumptions used

Geometry is a single-plate lug / padeye without cheek plates. Cheek-plate configurations are out of scope for v1 and require detailed analysis.
Load is applied in the plane of the lug. Out-of-plane bending from sling misalignment is treated via a user-supplied dynamic / skew factor only.
Behaviour assumed linear-elastic, isotropic, homogeneous. No plastic redistribution, residual stresses, or fatigue effects are considered.
Load line passes through the hole centre. Eccentricities between sling and lug centreline are not explicitly evaluated.
Allowable stresses are supplied by the user. The app does NOT apply any code-specific allowable factor (ASME BTH-1 $0.45 F_{y}$ , Eurocode $γ_{M}$ , DNV DAF, etc.) until the corresponding source clause has been supplied and validated.
Pin-to-hole fit is assumed reasonable (pin diameter slightly less than hole diameter). Extreme clearances or wear are not modelled.
Bearing stress is taken as the projected nominal value $σ_{b} = \frac{F}{d _{p} t}$ ; actual contact stress peaks are not resolved.
Fillet welds are symmetric about the load line. The weld group is analysed with $N = F cos θ$ , $V = F sin θ$ , $M = V \cdot h$ (in-plane bending), and throat stresses $σ_{⊥} = N / A_{w} + M / S_{w}$ , $τ_{⊥} = V / A_{w}$ . Out-of-plane (sling skew) effects and asymmetric weld runs remain out of scope in v1.

Source traceability

MECH_NET_SECTIONMechanics of Materials — net-section tension
Average tensile stress on the net cross-section through the pin hole: $σ = \frac{F}{( w - d ) t}$ . Classical identity; no code-specific allowable applied.
MECH_DOUBLE_SHEAR_OUTMechanics of Materials — double-plane shear-out
Average shear stress on two tear-out planes between hole and free edge: $τ = \frac{F}{2 L _{s} t}$ , where $L_{s} = a - \frac{d}{2}$ . Classical identity; no code-specific allowable applied.
MECH_BEARINGMechanics of Materials — bearing stress
Nominal bearing stress on the projected pin-on-plate area: $σ_{b} = \frac{F}{d _{p} t}$ . Classical identity; no code-specific allowable applied.
MECH_PIN_SHEARMechanics of Materials — pin double shear
Average shear stress on two pin cross-sections (single-lug in clevis): $τ = \frac{F}{2 A _{pin}}$ . Classical identity; no code-specific allowable applied.
MECH_FILLET_WELD_THROATMechanics of Materials — fillet weld throat resultant
Resultant throat stress on a fillet weld group with angle-aware demand decomposition $N = F cos θ$ , $V = F sin θ$ , $M = V \cdot h$ . Throat stresses $σ_{⊥} = \frac{N}{A _{w}} + \frac{M}{S _{w}}$ , $τ_{⊥} = \frac{V}{A _{w}}$ ; compared to the user-supplied shear allowable. No $γ_{M}$ or electrode-specific factor applied.
MECH_FILLET_WELD_VMMechanics of Materials — von Mises throat stress
Combined throat stress for a fillet weld group using the von Mises equivalent $σ_{eq} = σ_{⊥}^{2} + 3 (τ_{⊥}^{2} + τ_{∥}^{2})$ , compared to the user-supplied tensile allowable (falls back to $τ_{allow} 3$ ).
AISC_WELD_J24AISC 360-22 §J2.4 · 2022 · §J2.4, Eq. J2-5 (directional strength increase)
Nominal fillet-weld strength per unit throat area $F_{n w} = 0.60 F_{E X X} (1.0 + 0.5 sin^{1.5} θ)$ , where $θ$ is the angle between the line of action of the force resultant and the weld longitudinal axis. ASD safety factor $Ω = 2.0$ per §B3.2.
BTH1_NET_TENSIONASME BTH-1-2020 §3-3.3.1 · 2020 · §3-3.3.1 (eqs 3-45 through 3-48)
Static strength of pin-connected plate — tension on the effective net area either side of the pin hole, with $C_{r}$ reduction for pin/hole clearance and $b_{eff} = min (4 t, 0.6 b_{e} \frac{F _{u} D _{h}}{F _{y} b _{e}})$ . Allowable includes design factor $N_{d}$ per §3-1.3.
BTH1_DESIGN_FACTORASME BTH-1-2020 §3-1.3 · 2020 · §3-1.3
Design factor $N_{d}$ : $2.00$ for Design Category A, $3.00$ for Design Category B. Applied to all §3-3 allowables.
BTH1_FRACTUREASME BTH-1-2020 §3-3.3.2 · 2020 · §3-3.3.2 (eq 3-49)
Single-plane fracture strength of the plate beyond the pin hole.
BTH1_SHEAR_OUTASME BTH-1-2020 §3-3.3.3 · 2020 · §3-3.3.3 (eqs 3-50 through 3-52)
Double-plane shear-out strength: $A_{v} = 2 t [a + \frac{D _{p}}{2} (1 - cos φ)]$ , with $φ = 5 5^{\circ} \frac{D _{p}}{D _{h}}$ and allowable $P_{v} = \frac{0.70 F _{u} A _{v}}{1.20 N _{d}}$ .
BTH1_BEARINGASME BTH-1-2020 §3-3.3.4 · 2020 · §3-3.3.4 (eqs 3-53 / 3-54)
Pin bearing strength on the lug plate. Static bearing allowable $\frac{1.25 F _{y}}{N _{d}}$ ; rotating (Service Class $\geq 1$ ) reduced to $\frac{0.63 F _{y}}{N _{d}}$ .
BTH1_WELDASME BTH-1-2020 §3-3.4.3 · 2020 · §3-3.4.3 (eq 3-55)
Allowable fillet-weld shear on the effective throat $F_{v} = \frac{0.60 F _{E X X}}{1.20 N _{d}}$ . Extended to combined in-plane loading by applying the von Mises throat equivalent $σ_{eq} = σ_{⊥}^{2} + 3 τ_{⊥}^{2}$ against $F_{v} 3$ (Tresca-to-von Mises bridge consistent with AISC 360-22 Commentary on §J2.4).
EC3_PIN_GEOMETRYEN 1993-1-8:2005 §3.13.1 · 2005 · §3.13.1, Table 3.9
Geometric requirements for pin-connected plates: minimum plate thickness, minimum distances $a$ and $c$ from hole centre to plate edges as functions of $F_{y}$ , $γ_{M 0}$ , and $d_{0}$ .
EC3_PIN_SHEAREN 1993-1-8:2005 §3.13.2 · 2005 · §3.13.2, Table 3.10 (shear)
Pin shear resistance per plane: $F_{v, Rd} = \frac{0.6 A f _{u p}}{γ _{M 2}}$ . A single-lug / clevis assembly presents two shear planes.
EC3_PLATE_BEARINGEN 1993-1-8:2005 §3.13.2 · 2005 · §3.13.2, Table 3.10 (bearing)
Pin/plate bearing resistance: $F_{b, Rd} = \frac{1.5 t d f _{y}}{γ _{M 0}}$ .
EC3_PIN_BENDINGEN 1993-1-8:2005 §3.13.2 · 2005 · §3.13.2, Table 3.10 & Figure 3.11 (bending)
Pin bending resistance: $M_{Rd} = \frac{1.5 W _{el} f _{y p}}{γ _{M 0}}$ with $W_{el} = \frac{π d ^{3}}{32}$ . The demand $M_{Ed}$ follows Figure 3.11: $M_{Ed} = \frac{F _{Ed}}{8} (b + 4 c - 2 a)$ ; evaluated when the user supplies the shackle fork geometry (jaw thickness $a$ and either inside-jaw width $W$ or clearance $c$ ).
EC3_PIN_COMBINEDEN 1993-1-8:2005 §3.13.2 · 2005 · §3.13.2, Table 3.10 & Figure 3.11 (combined)
Combined shear + bending interaction on the pin: $(\frac{M _{Ed}}{M _{Rd}})^{2} + (\frac{V _{Ed}}{F _{v, Rd}})^{2} \leq 1$ . Gated on the same shackle fork geometry as the pin-bending check.
EC3_WELD_DIRECTIONALEN 1993-1-8:2005 §4.5.3.2 · 2005 · §4.5.3.2 (directional method)
Directional check for a fillet weld throat. Two criteria: $σ_{⊥}^{2} + 3 (τ_{⊥}^{2} + τ_{∥}^{2}) \leq \frac{f _{u}}{β _{w} γ _{M 2}}$ and $σ_{⊥} \leq \frac{0.9 f _{u}}{γ _{M 2}}$ . Correlation factor $β_{w}$ taken from Table 4.1 based on the weaker joined steel grade.
EC3_WELD_SIMPLIFIEDEN 1993-1-8:2005 §4.5.3.3 · 2005 · §4.5.3.3 (simplified method)
Simplified check on the weld throat as a vector shear: $F_{w, E d} \leq F_{w, R d} = f_{v w, d} a$ with $f_{v w, d} = \frac{f _{u} / 3}{β _{w} γ _{M 2}}$ . Conservative relative to the directional method; shown as a cross-check.
DNV_N001_DAFDNV-ST-N001 §16 · 2020-01 · Section 16 (lifting)
Dynamic amplification factor applied to the static rigging load. Values depend on lift weight and environment category (onshore light / standard / heavy; offshore sheltered / open sea). Defaults below are starting values — user must confirm against the project-specific clause.
DNV_N001_SKEWDNV-ST-N001 §16 · 2020-01 · Section 16 (lifting)
Skew-load factor for multi-sling lifts. Single-lug padeyes receive only the SKL multiplier on the sling force; governing SKL redistribution applies to multi-point rigging.

Example engineering report.