IQEG CALCULATION LAB
Fillet weld group stress
IQ-CAL-003 · Rev 0 Indicative · 11/11/2026 · Not a certificate
IQ Engineering Group · Sydney · IQ-CAL-003 · Fillet weld group stress · millimetres, kN, kNm, MPa unless noted
Connection
Actions at the group centroid C. x–x horizontal, y–y vertical.
Toggle lines
Glossary
- s
- Leg size of the fillet, mm. Throat tt = 0.707 s.
- B, D
- Plate width and depth of the group. The picture is a fixed template — only the notes update.
- On / off
- Gold lines are in the group. Dashed lines are omitted. End returns are 2s.
- C
- Centroid of the lines that are on.
- Red marker
- Governing throat — the point of maximum f*.
Weld group · x–x / y–y
Static plate. Gold strokes are welds on; dashed off. D and B are mill values — the picture does not scale.
Line group. Gold strokes are the welds. Dashed x–x / y–y through centroid C. Red marker is the governing throat. Actions at C: Vy 80 kN, Vx 0 kN, N 20 kN, Mxx 120 kNm, Myy 25 kNm, Mz 0 kNm. End returns 2s. le ≥ max(40 mm, 4s). Moment end plate — flange + web fillets. Mxx / Myy out of plane, V in plane.
Capacity
Calculation · separated by action
- 01
Design throat and capacity per millimetre of weld. φ SP = 0.80, GP = 0.60. tt = 0.707 s.
tt = 0.707 × 8 = 5.66 mm φ = 0.80 kr = 1.000 vw = 0.60 × fuw × tt × kr = 0.60 × 490 × 5.66 × 1.000 = 1,662.9 N/mm φvw = φ vw = 1,330.3 N/mm - 02
Same check as a throat shear stress. Compare τ* = f*/tt with τ_allow = φvw/tt = φ × 0.60 × fuw × kr.
τ_allow = 1,330.3 / 5.66 = 235.2 MPa - 03
Line-group properties about centroid C. Unit thickness 1 (or 2 if double fillet). Ixx about x–x, Iyy about y–y, J = Ixx + Iyy.
Lw = 3,042.0 mm C (100.0, 153.5) mm Ixx = 33,317,022 mm³ Iyy = 16,280,000 mm³ J = 49,597,022 mm³ - 04
Uniform force per unit length from direct actions. N is normal to the weld plane. Vx, Vy are in-plane.
fn(N) = N / Lw = 20 × 10³ / 3,042.0 = 6.57 N/mm fvx(Vx) = Vx / Lw = 0 × 10³ / 3,042.0 = 0.00 N/mm fvy(Vy) = Vy / Lw = 80 × 10³ / 3,042.0 = 26.30 N/mm - 05
Moment actions at a point (x, y) from C. Mxx and Myy are out-of-plane (normal force on the throat). Mz is in-plane torsion (shear on the throat).
Governing point (200.0, 307.0) on line T x = 100.0 y = 153.5 mm from C fn(Mxx) = Mxx·y / Ixx = 120×10⁶ × 153.5 / 33,317,022 = 552.87 N/mm fn(Myy) = Myy·x / Iyy = 25×10⁶ × 100.0 / 16,280,000 = 153.56 N/mm fvx(Mz) = −Mz·y / J = -0.00 fvy(Mz) = Mz·x / J = 0.00 N/mm - 06
Combine vectorially. f* is the resultant force per millimetre. τ* is the actual throat shear. Compare with φvw and τ_allow.
fn = fn(N)+fn(Mxx)+fn(Myy) = 6.57 + 552.87 + 153.56 = 713.01 N/mm fvx = fvx(Vx)+fvx(Mz) = 0.00 + -0.00 = 0.00 N/mm fvy = fvy(Vy)+fvy(Mz) = 26.30 + 0.00 = 26.30 N/mm f* = √(fn² + fvx² + fvy²) = 713.49 N/mm τ* = f*/tt = 126.1 MPa τ_allow = 235.2 MPa util = f*/φvw = 0.536
from N fn = 6.57 N/mm
from Mxx fn = 552.87 N/mm
from Myy fn = 153.56 N/mm
from Vx fvx = 0.00 N/mm
from Vy fvy = 26.30 N/mm
from Mz fvx = -0.00 fvy = 0.00 N/mm
combined f* 713.49 N/mm τ* = f*/tt = 126.1 MPa
φvw 1,330.3 N/mm τ_allow = 235.2 MPa util 0.536
Force per millimetre at the governing throat, by action. φvw is the design capacity.
| Line | x mm | y mm | fn(N) | fn(Mxx) | fn(Myy) | fn | fvx | fvy | f* N/mm | τ* MPa | util |
|---|---|---|---|---|---|---|---|---|---|---|---|
| T | 0.0 | 307.0 | 6.6 | 552.9 | -153.6 | 405.9 | 0.0 | 26.3 | 406.7 | 71.9 | 0.306 |
| T | 100.0 | 307.0 | 6.6 | 552.9 | 0.0 | 559.4 | 0.0 | 26.3 | 560.1 | 99.0 | 0.421 |
| T | 200.0 | 307.0 | 6.6 | 552.9 | 153.6 | 713.0 | 0.0 | 26.3 | 713.5 | 126.1 | 0.536 |
| Btm | 0.0 | 0.0 | 6.6 | -552.9 | -153.6 | -699.9 | 0.0 | 26.3 | 700.4 | 123.8 | 0.526 |
| Btm | 100.0 | 0.0 | 6.6 | -552.9 | 0.0 | -546.3 | 0.0 | 26.3 | 546.9 | 96.7 | 0.411 |
| Btm | 200.0 | 0.0 | 6.6 | -552.9 | 153.6 | -392.7 | 0.0 | 26.3 | 393.6 | 69.6 | 0.296 |
| L | 0.0 | 0.0 | 6.6 | -552.9 | -153.6 | -699.9 | 0.0 | 26.3 | 700.4 | 123.8 | 0.526 |
| L | 0.0 | 153.5 | 6.6 | 0.0 | -153.6 | -147.0 | 0.0 | 26.3 | 149.3 | 26.4 | 0.112 |
| L | 0.0 | 307.0 | 6.6 | 552.9 | -153.6 | 405.9 | 0.0 | 26.3 | 406.7 | 71.9 | 0.306 |
| R | 200.0 | 0.0 | 6.6 | -552.9 | 153.6 | -392.7 | 0.0 | 26.3 | 393.6 | 69.6 | 0.296 |
| R | 200.0 | 153.5 | 6.6 | 0.0 | 153.6 | 160.1 | 0.0 | 26.3 | 162.3 | 28.7 | 0.122 |
| R | 200.0 | 307.0 | 6.6 | 552.9 | 153.6 | 713.0 | 0.0 | 26.3 | 713.5 | 126.1 | 0.536 |
| web | 100.0 | 0.0 | 6.6 | -552.9 | 0.0 | -546.3 | 0.0 | 26.3 | 546.9 | 96.7 | 0.411 |
| web | 100.0 | 153.5 | 6.6 | 0.0 | 0.0 | 6.6 | 0.0 | 26.3 | 27.1 | 4.8 | 0.020 |
| web | 100.0 | 307.0 | 6.6 | 552.9 | 0.0 | 559.4 | 0.0 | 26.3 | 560.1 | 99.0 | 0.421 |
| midH | 0.0 | 153.5 | 6.6 | 0.0 | -153.6 | -147.0 | 0.0 | 26.3 | 149.3 | 26.4 | 0.112 |
| midH | 100.0 | 153.5 | 6.6 | 0.0 | 0.0 | 6.6 | 0.0 | 26.3 | 27.1 | 4.8 | 0.020 |
| midH | 200.0 | 153.5 | 6.6 | 0.0 | 153.6 | 160.1 | 0.0 | 26.3 | 162.3 | 28.7 | 0.122 |