Pultruded FRP structural shapes are manufactured in standard dimensional series that parallel steel sections but with wall thicknesses and fiber architectures optimized for the material's orthotropic stiffness. The section properties tabulated below are representative of commercially available profiles with a fiber volume fraction of approximately 55% and an isophthalic polyester or vinyl ester resin matrix. The span tables that follow give the maximum allowable simply supported span for a uniform load that produces a midspan deflection of L/180 — the practical governing limit for FRP beams in walkway and platform construction.
Section Properties — Standard I-Beams, Channels, and Square Tubes
| Shape | Depth (mm) |
Width (mm) |
Mass (kg/m) |
Ix (10⁶ mm⁴) |
Sx (10³ mm³) |
Iy (10⁶ mm⁴) |
Sy (10³ mm³) |
|---|---|---|---|---|---|---|---|
| I-Beam | 152 | 76 | 6.8 | 9.15 | 120 | 1.51 | 39.7 |
| I-Beam | 203 | 102 | 9.2 | 22.7 | 223 | 3.97 | 77.8 |
| I-Beam | 254 | 127 | 12.4 | 49.1 | 387 | 8.23 | 130 |
| Channel | 152 | 43 | 5.1 | 5.18 | 68.2 | 0.38 | 15.9 |
| Channel | 203 | 51 | 7.0 | 13.0 | 128 | 1.17 | 38.8 |
| Square Tube | 100 | 100 | 5.4 | 3.61 | 72.2 | 3.61 | 72.2 |
| Square Tube | 150 | 150 | 9.2 | 13.3 | 177 | 13.3 | 177 |
Allowable Uniform Load Spans — Deflection Limit L/180
| Shape | Depth (mm) | Max Span (m) at 2.5 kN/m² | Max Span (m) at 5.0 kN/m² | Max Span (m) at 7.5 kN/m² |
|---|---|---|---|---|
| I-Beam | 152 | 2.1 | 1.7 | 1.5 |
| I-Beam | 203 | 2.8 | 2.2 | 1.9 |
| I-Beam | 254 | 3.5 | 2.8 | 2.4 |
| Channel | 152 | 1.8 | 1.4 | 1.2 |
| Channel | 203 | 2.4 | 1.9 | 1.6 |
| Square Tube | 100 | 1.9 | 1.5 | 1.3 |
| Square Tube | 150 | 2.8 | 2.2 | 1.9 |
Notes: Span values are for simply supported beams with full lateral restraint of the compression flange. For unbraced spans, a lateral-torsional buckling check is required. Loads are uniformly distributed and include an allowance for the beam self-weight. The longitudinal modulus of elasticity EL is taken as 23 GPa for deflection calculations. For concentrated loads, cantilever conditions, or combined loading, use the full section properties to perform a custom deflection analysis.
Source: Advanced FRP Systems Engineering Data. Free to cite with link. Last verified: 2026-05-15.
For complete section property tables and custom profile options, see FRP I-Beam and related structural shapes.