IQ-CAL-006REV 0NOT A CERTIFICATE
IQEG CALCULATION LAB
Built-up section inertia
IQ-CAL-006 · Rev 0 Indicative · 11/11/2026 · Not a certificate
INPUTS + RESULTSUNITS AS TABULATED
IQ Engineering Group · Sydney · IQ-CAL-006 · Built-up section inertia · millimetres, kN, kNm, MPa unless noted
Geometry — mm
s is inside face to inside face, independent of flange width. TF 400×25, webs 800×8/10, s 290, BF 350×20. Overall d = 845 mm.
Glossary
- Ixx, Iyy
- Second moments about the centroidal x–x (strong) and y–y (weak) axes. mm⁴.
- Z
- Elastic modulus I / ymax. σ = M / Z.
- s i/i
- Inside-face to inside-face between webs. Independent of flange width.
- ȳ, yt
- Distance from the bottom fibre to the centroid.
Assembled section
TF 400×25 · WA 8×800 · WB 10×800 · s 290 inside · BF 350×20
Properties
A — mm²31,400
Ixx — 10⁶ mm⁴3,596.9
Iyy — 10⁶ mm⁴527.0
Zxx — 10³ mm³7,819.8
Zyy — 10³ mm³2,634.9
rxx — mm338.5
ryy — mm129.5
ȳ — mm460.0
d — mm845
s c/c — mm299.0
Five fibres · σ = N/A + Mxx y/Ixx + Myy x/Iyy
| Pt | x mm | y mm | σN | σMxx | σMyy | σ MPa | σvm |
|---|---|---|---|---|---|---|---|
| P1 | -200.0 | 385.0 | 0.0 | 42.8 | -30.4 | 12.5 | 12.5 |
| P2 | 200.0 | 385.0 | 0.0 | 42.8 | 30.4 | 73.2 | 73.2 |
| P3 | 0.0 | 360.0 | 0.0 | 40.0 | 0.0 | 40.0 | 40.0 |
| P4 | -175.0 | -460.0 | 0.0 | -51.2 | -26.6 | -77.7 | 77.7 |
| P5 | 175.0 | -460.0 | 0.0 | -51.2 | 26.6 | -24.6 | 24.6 |
σvm / fy 0.26 · PASS
SECTION · FIVE FIBRES
- 01
Area and second moments about the centroid.
A = 31,400 mm² Ixx = 3,596.9×10⁶ mm⁴ Iyy = 527.0×10⁶ mm⁴ - 02
σ = N/A + Mxx y/Ixx + Myy x/Iyy. y from the NA, positive toward the top fibre.
Governing P4 x=-175.0 mm y=-460.0 mm σ=-77.7 MPa σvm=77.7 MPa - 03
Utilisation against fy (indicative, not a member check).
σvm / fy = 0.26