Section properties (calculated, example sizes)
Computed from geometry for a parallel-flange I-section at 1.9 g/cm³, ignoring corner radii. Example sections only; actual catalogue sizes and thicknesses differ. I is the second moment of area about the strong axis, S the section modulus.
| Depth × flange width (mm) | Flange / web thickness (mm) | kg/m | I (cm⁴) | S (cm³) |
|---|---|---|---|---|
| 100 × 50 | 6 / 6 | 2.1 | 167 | 33 |
| 127 × 63 | 6.4 / 6.4 | 2.9 | 373 | 59 |
| 152 × 76 | 8 / 8 | 4.4 | 799 | 105 |
| 203 × 101 | 9.5 / 9.5 | 7.0 | 2291 | 226 |
| 254 × 127 | 9.5 / 9.5 | 8.8 | 4635 | 365 |
| 305 × 152 | 12.7 / 9.5 | 12.4 | 9982 | 655 |
Worked load check
The 203×101 section above (I = 2291 cm⁴, E = 20 GPa, a conservative value) on a 3 m simply supported span, limited to span/200 = 15 mm. From δ = 5wL⁴/(384EI):
wmax = 15 × 384 × 20000 × 22909043 / (5 × 3000⁴) = 6.52 N/mm = 6.52 kN/m (bending-only estimate)
Shear deflection and creep are not included and are significant for FRP, so the real allowable load is lower; check the supplier’s table and use a designer experienced with pultruded FRP. For the method and an equal-stiffness comparison with steel see fiberglass vs steel beams.
Typical material data
| Property (along the fibres) | Typical range |
|---|---|
| Tensile strength | 250–400 MPa |
| Flexural modulus | 10–17 GPa |
| Tensile modulus | 17–25 GPa |
| Density | 1.8–2.0 g/cm³ |
Ranges only. Ask for test reports of the exact resin and glass content.
Where I-beams, H-profiles and flange beams are used
- platforms and mezzanines in chemical, water and food plants;
- cooling-tower and coastal structures;
- bridge and walkway framing, cable-tray supports;
- areas where non-conductive or non-magnetic framing is needed.
H-profiles and wide-flange beams follow the same design logic; ask for the section you need. Compare with steel: FRP vs steel.
Send us your requirement
Guangdong Haikuo Composite Materials Co., Ltd. (Huizhou, Guangdong) designs pultrusion moulds in-house and produces custom FRP profiles. Send a drawing, a sample or just the application and the environment, and we will tell you what is feasible.
Email: helena@frphk.cn | Phone: +86 189 5198 8522