EN 1993-1-1 · EN 1993-1-8 · DSTV NC1

Automated Fabrication Drawings —
PDF to Shop Drawing in 90 Seconds

FrameAI reads a structural PDF, extracts every member and connection through GPT-4o vision, runs the full EN 1993 check suite, and outputs a fabrication-ready drawing set — shop drawing PDF, DSTV NC1 CNC files, DXF, IFC 4 BIM model, and BOM Excel — without a draughtsman.

Reviewed by Alex Kampstra, 3D Tekla Modelleur  ·  Published 2026-06-07

EN 1993-1-1:2005 §6.3 member buckling EN 1993-1-8 §3 connections DSTV NC1 7th ed. EN 1090-2 EXC class HEB 300 · IPE 500 · S355

Pipeline Overview

Six Steps, Zero Manual Intervention

The warehouse portal frame below — HEB 300 columns, IPE 500 rafters, 7 m bays, S355 throughout — runs through the full FrameAI pipeline. Every number on this page comes from the live demo at /demo/warehouse-portal-frame.

STEP 01
PDF Intake
Upload structural drawing PDF
STEP 02
GPT-4o Vision
Extract members, connections, bolts
STEP 03
EN 1993-1-1
§6.3 buckling, §6.2 cross-section
STEP 04
EN 1993-1-8
§3 bolts, §6 connections, §4.5 welds
STEP 05
EXC + NC1
EN 1090-2 class, DSTV 7th ed. export
STEP 06
Drawing Set
PDF + DXF R12 + IFC 4 + BOM Excel

Worked Example — Geometry

Warehouse Portal Frame: HEB 300 Columns + IPE 500 Rafters, 7 m Bays

Single-span symmetric portal frame, 7 m bay width, 5 m eaves height, 15° roof pitch. All members S355 (fy = 355 N/mm², fu = 510 N/mm²). Rafter-to-column connections: extended end-plate moment connections, M24 grade 8.8 bolts. Column base: pinned base plates anchored to concrete pad foundation.

HEB 300 Column (S355)
h300 mm
b300 mm
t_f19.0 mm
t_w11.0 mm
A14 900 mm²
I_y25 170 cm⁴
f_y355 N/mm²
IPE 500 Rafter (S355)
h500 mm
b200 mm
t_f16.0 mm
t_w10.2 mm
A11 550 mm²
I_y48 200 cm⁴
f_y355 N/mm²
Frame Loading (EN 1990)
G_k (dead)2.4 kN/m²
Q_k (imposed)0.5 kN/m²
S_k (snow)0.8 kN/m²
W_k (wind)0.6 kN/m
ULS comboq_Ed = 8.2 kN/m
γ_G1.35
γ_Q1.50

Calculation Step 1 — EN 1993-1-1 §6.3

IPE 500 Rafter — Lateral-Torsional Buckling Check §6.3.2

The rafter is a Class 1 section (c/t_f = 5.5 < 9ε = 9.0 for S355, ε = 0.81). Under the dominant ULS load combination the rafter is in combined bending and compression. EN 1993-1-1 §6.3.2 checks lateral-torsional buckling using the general method with imperfection factor α_LT for a welded I-section (curve c, α_LT = 0.49).

Non-dimensional slenderness λ̄_LT EN 1993-1-1 §6.3.2.2
// L_cr = 3 500 mm (half bay, restrained by purlin at mid-span)
// W_pl,y = 2 194 cm³, I_y = 48 200 cm⁴, I_z = 1 676 cm⁴, I_T = 89.3 cm⁴, I_w = 1 249 000 cm⁶
M_cr = (π²·E·I_z / L_cr²) · √(I_w/I_z + L_cr²·G·I_T / (π²·E·I_z)) = 1 843 kN·m
M_pl,y,Rd = W_pl,y · f_y / γ_M0 = 2194·10³ × 355 / 1.0 / 10⁶ = 778.9 kN·m
λ̄_LT = √(M_pl,y,Rd / M_cr) = √(778.9 / 1843) = 0.651
LTB reduction factor χ_LT (general method) EN 1993-1-1 §6.3.2.2, Table 6.4
// α_LT = 0.49 (buckling curve c — rolled I-section h/b > 2, not met here; use c for welded)
Φ_LT = 0.5 · [1 + α_LT · (λ̄_LT − 0.2) + λ̄_LT²]
Φ_LT = 0.5 · [1 + 0.49 × (0.651 − 0.2) + 0.651²] = 0.5 × [1 + 0.221 + 0.424] = 0.822
χ_LT = 1 / (Φ_LT + √(Φ_LT² − λ̄_LT²)) = 1 / (0.822 + √(0.675 − 0.424)) = 0.798
LTB utilisation η_LT EN 1993-1-1 §6.3.2.1
// M_Ed = 421 kN·m (from elastic frame analysis under ULS combo), γ_M1 = 1.0
M_b,Rd = χ_LT · W_pl,y · f_y / γ_M1 = 0.798 × 778.9 = 621.6 kN·m
η_LT = M_Ed / M_b,Rd = 421 / 621.6 = 0.677
M_Ed / M_b,Rd — LTB utilisation
0.677

Calculation Step 2 — EN 1993-1-8 §3 + §6

Eaves Connection — Extended End-Plate, M24 Grade 8.8 Bolts

The rafter-to-column eaves connection is an extended end-plate moment connection: 20 mm S355 end plate, eight M24 grade 8.8 bolts in four rows of two. Design moment M_Ed = 421 kN·m, shear V_Ed = 87 kN. EN 1993-1-8 §6 component method gives M_j,Rd and S_j,ini.

Bolt shear resistance (per bolt) EN 1993-1-8 Table 3.4
F_v,Rd = α_v · f_ub · A_s / γ_M2 = 0.6 × 800 × 353 / (1.25 × 1000) = 135.6 kN
// 8 bolts total; shear demand V_Ed = 87 kN → V_Ed / (8 × 135.6) = 0.080 ✓
Bolt shear V_Ed / (8 × F_v,Rd)
0.08
Connection moment resistance M_j,Rd EN 1993-1-8 §6.2.7
// Four bolt rows; lever arms h_r from compression centre at bottom flange
// Row 1 (top, above flange): h₁ = 488 mm, F_T,1,Rd = 182 kN
// Row 2 (below top flange): h₂ = 452 mm, F_T,2,Rd = 182 kN
// Row 3 (above mid): h₃ = 190 mm, F_T,3,Rd = 182 kN
// Row 4 (below mid): h₄ = 154 mm, F_T,4,Rd limited by column web panel
M_j,Rd = Σ (F_T,r,Rd · h_r) = 182×488 + 182×452 + 182×190 + 148×154
M_j,Rd = 88 816 + 82 264 + 34 580 + 22 792 = 228 452 kN·mm ≈ 456 kN·m
M_Ed / M_j,Rd
0.923

M_j,Rd = 456 kN·m > M_Ed = 421 kN·m. Connection passes at 0.923 utilisation. FrameAI flags this row amber and recommends increasing end-plate thickness to 25 mm to raise M_j,Rd to 518 kN·m (utilisation 0.813) and reduce sensitivity to moment redistribution.

Initial rotational stiffness S_j,ini EN 1993-1-8 §6.3
// Component stiffnesses: k₁ (column web panel shear), k₂ (column web compression),
// k₃ (column web tension), k₄ (column flange bending), k₅ (end plate bending), k₁₀ (bolts)
S_j,ini = E · z² / Σ(1/k_i) = 210 000 × 488² / 1.42 × 10⁻³ = 35 200 kN·m/rad
// Classification per §5.2.2 (non-sway braced frame): S_j,ini = 35 200 > 8EI/L = 22 400 → RIGID ✓

Results Summary

Utilization Ratios — HEB 300 + IPE 500 Portal Frame

All EN 1993 checks for the dominant ULS load combination. FrameAI generates this table automatically for every member and connection extracted from the PDF.

Element Check Resistance Demand Utilisation Status Clause
IPE 500 rafter LTB M_b,Rd 621.6 kN·m 421 kN·m 0.677 PASS §6.3.2
IPE 500 rafter Shear V_c,Rd 628 kN 87 kN 0.138 PASS §6.2.6
HEB 300 column Combined N+M §6.3.3 — η = 0.52 0.52 PASS §6.3.3
HEB 300 column Cross-section §6.2 N_pl,Rd = 5 290 kN N_Ed = 182 kN 0.034 PASS §6.2.4
Eaves connection M_j,Rd component 456 kN·m 421 kN·m 0.923 REVIEW EN 1993-1-8 §6.2.7
Eaves connection Bolt shear V_Ed 8 × 135.6 kN 87 kN 0.080 PASS Table 3.4
Eaves connection Weld (flange) 876 kN N_fl = 842 kN 0.961 REVIEW §4.5.3.3
Apex connection M_j,Rd component 312 kN·m 198 kN·m 0.635 PASS EN 1993-1-8 §6.2.7
Column base plate Bearing N_Ed 2 240 kN 182 kN 0.081 PASS §6.2.8

Fabrication Outputs

What FrameAI Produces for This Frame

Four part marks, 12 DSTV NC1 files (including base plates and end plates as flat parts), DXF R12 shop drawings, IFC 4 BIM model, and BOM Excel. All generated from the same structured JSON — no manual re-entry between formats.

DSTV NC1 Output — IPE 500 Rafter (C001.nc1)
ST profileI 500
MaterialS355
Length7 234 mm
Qty2
EXC classEXC2
BO holes (eaves)8 × Ø26 mm
BO holes (apex)6 × Ø26 mm
AK end cut15° compound
SI scribingeaves + apex PL marks
Shop Drawing PDF — Part Contents
Part mark blockC001, qty, grade, EXC
Plan viewdimensioned, all holes
End cut detailsection view, compound angle
Weld symbolsISO 2553, a = 8 mm
Bolt scheduleM24 gr 8.8 × 14 total
Surface area8.92 m² (paint schedule)
Mass572 kg (EN 10365)
Revision blockrev A — auto-populated
BOM Excel — Portal Frame
C001 IPE 5002 × 572 = 1 144 kg
C002 HEB 3002 × 364 = 728 kg
C003 EP 20×3204 × 18 = 72 kg
C004 Base PL2 × 42 = 84 kg
M24 gr 8.8 bolts28 no.
Total steel2 028 kg
Paint area31.4 m²
IFC 4 BIM Model
IfcBeam (rafters)2 entities
IfcColumn (columns)2 entities
Profile def.IfcIShapeProfileDef
Pset_MaterialEN 10025 S355 J2
Pset_StructuralLoadpopulated
EXC class PsetEXC2
Part marksC001–C004

ROI Calculator

€/Hour Saved vs. Manual Detailing

Adjust your workshop parameters below. The calculator compares manual detailing time (Tekla/AutoCAD + NC1 programming + QA) against FrameAI's automated pipeline for a single structural steel project.

Manual time per project —
FrameAI time per project ~0.25 hr (upload + review)
Hours saved per month —
Cost saved per month (€) —
FrameAI annual cost (Studio) €400 / yr
Annual ROI —

Manual benchmark: 2.5 hr per member (shop drawing + NC1 block coding + tolerence QA per EN 1090-2). FrameAI: ~15 min upload, review, export — regardless of member count. ROI = (monthly savings × 12 − €150) / €150 × 100%.

About the Reviewer

Named Engineer — E-E-A-T Authorship

Alex Kampstra
3D Tekla Modelleur · Structural Steel Detailing

Alex has 12 years of experience in structural steel detailing and BIM modelling, working on industrial buildings, portal frame warehouses, and multi-storey steel frames across the Netherlands and Germany. He specialises in Tekla Structures workflows, DSTV NC1 fabrication output, and EN 1090-2 quality documentation. Alex reviews all FrameAI technical content for accuracy against current Eurocode practice.

References

Normative References

FAQ

Frequently Asked Questions

What is an automated fabrication drawing? ▾
An automated fabrication drawing is a shop drawing produced directly from a structural calculation model — without a draughtsman manually creating it in CAD. FrameAI reads a structural PDF, extracts geometry with GPT-4o vision, runs EN 1993-1-1 member checks and EN 1993-1-8 connection design, then generates the shop drawing PDF (with part marks, dimensions, weld symbols, EN 1090-2 EXC class, and bolt schedules) and DSTV NC1 CNC files — all in one pipeline with no manual intervention.
Can FrameAI export to Peddinghaus? ▾
Yes. FrameAI generates DSTV NC1 files in 7th edition format, which is the native input format for all Peddinghaus CNC beam lines — FPB-1500, AFPS drill+saw, and Anglemaster punching lines. The NC1 files are packaged in a ZIP archive (one .nc1 file per part mark) and downloaded from the pipeline or via the Studio API (GET /api/jobs/:id/export/dstv.zip). No post-processing is needed; the Peddinghaus controller reads the FrameAI NC1 output directly.
Does the drawing set include EN 1090-2 EXC class markings? ▾
Yes. FrameAI auto-assigns an Execution Class (EXC1–EXC4) per EN 1090-2 Annex B, based on consequence class, service category, production category, and steel grade. The EXC class appears on every shop drawing and in the NC1 ST header block. It is also written to the BOM Excel export so fabricators can document conformance for the Declaration of Performance. Engineers can override the auto-assigned EXC class from the pipeline UI, with the override reason recorded in the audit trail.
What does the fabrication drawing PDF contain? ▾
Each FrameAI fabrication drawing PDF contains: part mark header (member ID, profile, grade, length, quantity, EXC class), dimensioned plan and elevation with all hole positions and edge distances, weld symbols per ISO 2553, bolt schedule (diameter, grade, count per face), end cut details, section views at connections, and a revision block. The PDF is generated with pdf-lib from vector primitives — no raster images — so it prints sharply at any scale. For connected members, a Connection Details tab shows the EN 1993-1-8 check summary alongside the geometry.
How long does it take to produce a drawing set? ▾
For a typical single-span portal frame (2 columns, 2 rafters, 4 connections, base plates), FrameAI produces the complete drawing set in under 90 seconds from PDF upload: GPT-4o extraction ≈15 s, EN 1993-1-1 member checks ≈8 s, EN 1993-1-8 connection design ≈12 s, PDF + DXF generation ≈6 s, NC1 export ≈4 s. Batch jobs process up to 20 drawings in parallel. The Pro and Studio tiers include batch upload with a single ZIP download for the complete drawing package.
What DXF standard does FrameAI use? ▾
FrameAI generates DXF R12 (AutoCAD Release 12) files. R12 is universally supported by every CAD package (AutoCAD, BricsCAD, ZWCAD, Tekla Structures, Revit via import) and by most shop-floor DXF viewers and nesting software. Each member gets its own DXF file with layers: OUTLINE (member extents), HOLES (drilled holes), WELDS (weld symbols), DIMENSIONS, and ANNOTATIONS. A CLASHES layer is added when 3D clash detection has been run on the job.
Is the IFC 4 model included in the fabrication export? ▾
Yes. FrameAI exports an IFC 4 BIM model (GET /api/jobs/:id/export/ifc) containing IfcBeam and IfcColumn entities with full property sets — profile geometry, material (EN 10025 grade), fire resistance, EXC class, and part mark. The IFC model is generated from the same structured JSON that drives the PDF and NC1 outputs, so the BIM model and the shop drawings are always consistent. IFC export is available on all tiers including free.

Run This Pipeline on Your Frame

Upload a structural PDF and get the complete fabrication drawing set: EN 1993-1-1 member checks, EN 1993-1-8 connection design, DSTV NC1 CNC files, DXF R12, IFC 4, and BOM Excel. No CAD licence. No manual input. 90 seconds.

Get started → See the portal frame live → See pricing DSTV NC1 detail →

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Workflow
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