A serious calculator for preliminary lug design.
Single-plate lifting lugs sized in seconds — transparent assumptions, traceable sources, and a printable report.
Every active check is guarded by a hand-computed benchmark derived from the published clause equations.
Preliminary design, done properly.
The tool covers the checks you'd do by hand in the first pass of a lug design — faster, with clearer traceability and a report you can actually share.
Every implemented check prints the assumptions it relies on — load in plane, linear-elastic, user-supplied allowables, single-plate geometry. No hidden factors.
Every check links to a source reference with edition and clause number. Mechanics identities are labelled public-domain; ASME BTH-1, EN 1993-1-8, and DNV-ST-N001 are each guarded by a hand-computed benchmark.
All applicable checks run on every input change. The governing failure mode is selected from the methodology you pick; the other families appear alongside as cross-checks.
Edge distance below d_hole, large lifting angle, unusual pin-hole clearance, offshore — out-of-scope cases are flagged automatically with a recommendation to use a detailed method or FEA.
Structured report with project metadata, inputs summary, schematics, result table, source traceability, and revision stamp. PDF export is structured pages — not a screenshot.
Inputs live in the URL and in your browser. Share a link, reload, hand it off. The app doesn't need to own your data.
We don't claim "all standards supported." We tell you exactly which clauses are implemented, which route drives the governing utilisation, and what's out of scope.
Net-section tension, double-plane shear-out, pin bearing, pin double shear, and a full angle-aware fillet weld group (throat resultant + von Mises). Classical identities used as cross-checks and for the live report.
Pin-connected plate static strength (§3-3.3.1 – §3-3.3.4) and fillet-weld allowable (§3-3.4.3) extended to a combined-stress interpretation, with Design Category Nd and static/rotating service-class bearing allowables.
Pin-plate geometry (Table 3.9), pin shear and plate bearing (Table 3.10), pin bending + combined shear/bending (Figure 3.11, Table 3.10). New: directional and simplified fillet-weld methods on the lug base weld group (§4.5.3.2 / §4.5.3.3), β_w and γ_M2 user-editable.
Fillet weld nominal strength with the directional increase and ASD . Runs alongside the mechanics weld checks; uses the same electrode value as the BTH-1 allowable.
Weld-symbol convention used by the schematic: the fillet leg is shown on the symbol, closed-perimeter groups get the weld-all-around circle, and the schematic side view carries the throat dimension.
Dynamic amplification and skew-load factors from Section 16. Applied on the demand side of every resistance check — including all weld checks — when the DNV route is selected; project values can override the defaults.
A report that reads like engineering, not like marketing.
Structured sections: project metadata, inputs summary, live schematics, result table with demand / capacity / utilisation per check, governing check, warnings, source traceability, and a timestamped revision note. PDF export is rendered as structured pages — not a blurry screenshot.
Figures generated live from the inputs above. Geometry is drawn to scale within each viewBox; use as a qualitative check only — not a CAD drawing.
| Check | Demand | Capacity | U | Status |
|---|---|---|---|---|
| Net-section tension | 33.78 MPa | 213.00 MPa | 0.159 | pass |
| Shear-out (2-plane)governing | 41.67 MPa | 123.00 MPa | 0.339 | pass |
| Pin bearing | 100.00 MPa | 320.00 MPa | 0.313 | pass |
| Pin double shear | 25.46 MPa | 220.00 MPa | 0.116 | pass |
| Weld throat — von Mises | 49.08 MPa | 207.00 MPa | 0.237 | pass |
| Weld resultant |R| | 49.08 MPa | 207.00 MPa | 0.237 | pass |
| Check | Demand | Capacity | U | Status |
|---|---|---|---|---|
| Net-section §3-3.3.1 | 33.78 MPa | 179.73 MPa | 0.188 | pass |
| Shear-out §3-3.3.2 | 41.67 MPa | 83.56 MPa | 0.499 | pass |
| Bearing §3-3.3.3 | 100.00 MPa | 177.50 MPa | 0.563 | pass |
| Weld allowable §3-3.4.3 | 49.08 MPa | 110.42 MPa | 0.444 | pass |
| AISC 360-22 §J2.4 weld | 49.08 MPa | 120.31 MPa | 0.408 | pass |
- Load applied in the plane of the plate — no out-of-plane component.
- Linearly elastic material response. No plastic redistribution.
- Allowable stresses are user-supplied; no standard-derived reduction factors applied in the mechanics route.
- Single-plate geometry. Not applicable to multi-plate or cheek-plate arrangements.
- Corrosion allowance deducted from all plate thicknesses before checks.
- Pin perfectly fits hole within clearance; no eccentric bearing assumed.
- Weld group carries in-plane forces only; out-of-plane effects not included.
- Fillet weld topology: two parallel side welds. End welds not included.