Bolted end plate moment connection to EN 1993-1-8
A 457 × 191 × 67 beam on a 305 × 305 × 137 column with an extended 20 mm end plate and M20 class 10.9 bolts, carrying 150 kNm and 120 kN: the bolt-row T-stubs, the compression zone, the column web panel, the moment resistance, bolt shear and the welds. The numbers come from the free STATIX end plate calculator, which runs the STATIX app’s connection engine.
1. The problem
| Input | Value |
|---|---|
| Beam | 457 × 191 × 67 I-section, S355 |
| Column | 305 × 305 × 137 H-section, S355, connection on the column flange |
| End plate | 200 × 555 × 20 mm, extended above the beam top flange |
| Bolts | M20 class 10.9, gauge 100 mm: one row above the top flange and two rows below it (2 bolts per row) |
| Welds | 8 mm fillets to the flanges and the web |
| Design actions (factored) | M = 150 kNm (hogging), V = 120 kN, N = 0, braced frame |
The end plate calculator uses the component method of EN 1993-1-8 §6.2 on the STATIX app's connection engine: every bolt row gets a tension resistance from the weakest of its T-stubs and the bolts, the rows act alone and in groups, and the compression side, the column web and the welds are checked against the same forces.
2. The tension rows (6.2.6, 6.2.7)
For the outer row above the flange, the end plate in bending (6.2.6.5), the column flange in bending (6.2.6.4) and the bolts in tension (3.6.1, two bolts) each give 353 kN, and the column web in tension (6.2.6.3) gives 787 kN. The row carries 153 kN, so it works at 43%. The inner rows below the flange add their own resistances, limited by the group patterns of Table 6.4 / 6.6, which is why a row's share falls when it is close to another row.
3. The compression side and the web panel
column web in compression (6.2.6.2): 938 kN (40%)
beam flange and web in compression (6.2.6.7): 1 185 kN (32%)
column web panel in shear (6.2.6.1): 376 ≤ 886 kN (42%)
The column web stress factor kwc is taken as 1,0 because the column's own axial stress is not an input on this page. The calculator flags this, and it does not change the verdict here.
4. Moment resistance (6.2.7)
The moment resistance is the sum of each row's effective tension times its lever arm to the centre of compression:
5. Shear (Table 3.4)
The vertical shear goes to the bolts: rows that carry little tension take shear at their full resistance, and the rows working in tension add only 0,28 Fv,Rd each, as SCI P398 sets out:
bolt bearing on the plate: 20,0 ≤ 150 kN per bolt (13%)
shear and tension in one bolt: Fv/Fv,Rd + Ft/(1,4 Ft,Rd) = 0,51 ≤ 1,0
6. Welds and detailing
- Flange weld (directional method, 4.5.3): 376 ≤ 629 kN (60%). Web weld: 120 ≤ 1 155 kN (10%).
- Full-strength web weld (SCI P398 step 7, a rule for the weld size, not an applied action): 91% in tension.
- Bolt spacing: every end and edge distance and pitch is inside the limits of Table 3.3; the top row sits clear of the flange weld toe, and the beam sits within the plate.
7. Result
| Check | Result |
|---|---|
| Tension row 1 (plate, column flange, bolts) | 153 ≤ 353 kN (43%) |
| Column web in compression | 376 ≤ 938 kN (40%) |
| Column web panel shear | 376 ≤ 886 kN (42%) |
| Moment resistance Mj,Rd | 150 ≤ 347 kNm (43%) |
| Bolt shear group Vj,Rd | 120 ≤ 165 kN (73%), governs |
| Flange weld | 60% |
The joint is adequate at 73%, governed by vertical shear on the bolts. A third bolt in the shear zone, or a larger bolt, lifts Vj,Rd first; the moment side still has more than twice the capacity it needs.
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