FRP I-beams provide exceptional strength-to-weight ratio for structural applications in corrosive environments
FRP I-beams are among the most efficient structural shapes available for applications that need high load-bearing capacity at minimal weight. The I-beam geometry concentrates material at the flanges, where stress is highest, making it well suited to bending loads. Manufactured via pultrusion, FRP I-beams combine that efficient geometry with the inherent advantages of fiberglass composite: corrosion resistance, electrical insulation, and durability.
At Guangdong Haikuo Composite Material Co., Ltd, we manufacture FRP I-beams in standard and custom sizes for structural applications worldwide.
1. Why Choose FRP I-Beams Over Steel
The choice between FRP and steel I-beams comes down to your specific application requirements:
| Factor | FRP I-Beam | Steel I-Beam | Advantage |
|---|---|---|---|
| Weight | 75-80% lighter | Baseline | FRP |
| Corrosion Resistance | Excellent | Requires coating | FRP |
| Electrical | Non-conductive | Conductive | FRP |
| Maintenance | Minimal | Repainting required | FRP |
| Installation | 30-50% faster | Standard | FRP |
| Initial Cost | Higher | Lower | Steel (initial) |
| Lifecycle Cost (20yr) | 40-60% lower | Higher | FRP |
2. Standard FRP I-Beam Sizes
FRP I-beams come in a range of standard sizes:
| Designation | Depth (mm) | Flange Width (mm) | Web Thickness (mm) | Flange Thickness (mm) | Weight (kg/m) |
|---|---|---|---|---|---|
| I-100 | 100 | 55 | 6 | 8 | 5.5 |
| I-125 | 125 | 65 | 6 | 9 | 7.2 |
| I-150 | 150 | 75 | 7 | 10 | 9.8 |
| I-175 | 175 | 90 | 7 | 11 | 12.5 |
| I-200 | 200 | 100 | 8 | 12 | 15.8 |
| I-250 | 250 | 125 | 9 | 14 | 23.5 |
| I-300 | 300 | 150 | 10 | 16 | 33.0 |
3. Mechanical Properties
Typical mechanical properties for pultruded FRP I-beams:
| Property | Value (Longitudinal) | Test Method |
|---|---|---|
| Tensile Strength | 250-400 MPa | ASTM D638 |
| Tensile Modulus | 17-25 GPa | ASTM D638 |
| Flexural Strength | 200-350 MPa | ASTM D790 |
| Flexural Modulus | 10-17 GPa | ASTM D790 |
| Compressive Strength | 150-250 MPa | ASTM D695 |
| Shear Strength | 20-30 MPa | ASTM D2344 |
| Density | 1.8-2.2 g/cm³ | ASTM D792 |
4. Section Properties
Typical section properties for standard FRP I-beams:
| Size | Area (mm²) | Ix (cm⁴) | Sx (cm³) | rx (mm) | Zx (cm³) |
|---|---|---|---|---|---|
| I-100 | 2,800 | 480 | 96 | 41 | 110 |
| I-125 | 3,650 | 980 | 157 | 52 | 180 |
| I-150 | 4,950 | 1,890 | 252 | 62 | 290 |
| I-200 | 7,980 | 5,400 | 540 | 82 | 620 |
| I-250 | 11,880 | 12,500 | 1,000 | 103 | 1,150 |
| I-300 | 16,650 | 25,200 | 1,680 | 123 | 1,930 |
5. Load Tables: Allowable Uniform Distributed Load (kN/m)
Based on simple span, a deflection limit of L/200, and an allowable flexural stress of 100 MPa:
| Span (m) | I-100 | I-125 | I-150 | I-200 | I-250 | I-300 |
|---|---|---|---|---|---|---|
| 2.0 | 5.5 | 9.0 | 14.5 | 31.0 | 57.5 | 96.5 |
| 3.0 | 2.4 | 4.0 | 6.4 | 13.8 | 25.6 | 42.9 |
| 4.0 | 1.4 | 2.3 | 3.6 | 7.8 | 14.4 | 24.1 |
| 5.0 | 0.9 | 1.4 | 2.3 | 5.0 | 9.2 | 15.4 |
| 6.0 | 0.6 | 1.0 | 1.6 | 3.5 | 6.4 | 10.7 |
Design Note
These values are for preliminary selection only. Final design should be performed by a qualified structural engineer familiar with pultruded FRP materials, applying appropriate safety factors and checking all limit states.
6. Primary Applications of FRP I-Beams
6.1 Marine and Offshore
- Deck supports and beams: used as structural supports for offshore decks, where the high strength-to-weight ratio enables significant topside weight reduction and improves platform buoyancy.
- Offshore platform walkways: combined with FRP grating, these beams create durable, slip-resistant walkways that hold up structurally even in wave splash zones.
- Boat lift structures: well suited to lifting frames in marinas since they resist moisture-laden air and don’t produce rust streaks that can stain or damage vessel hulls.
- Dock pilings and framing: offer a service life exceeding 50 years in submerged or semi-submerged marine conditions, resisting both oxidation and marine organisms.
6.2 Chemical and Industrial
- Process platform structures: used extensively in electroplating plants and wastewater treatment facilities, where acidic fumes would compromise steel structures quickly.
- Equipment supports: support heavy equipment like reaction vessels and storage tanks — their natural vibration-damping properties help protect connected sensitive machinery.
- Pipe rack systems: used to support piping carrying corrosive substances; as a poor thermal conductor, FRP reduces heat transfer between the pipe and the support.
- Corrosive environment structural members: important for cooling towers, where I-beams withstand constant high humidity and the chemical treatments used in water cycles.
6.3 Electrical Utilities
- Transformer mounting structures: removes the risk of eddy current losses and unwanted electrical paths while providing the mechanical strength heavy equipment needs.
- Substation platforms: provide a safety barrier in high-voltage areas, protecting maintenance personnel from accidental grounding or electrocution.
- Cable tray supports: support large cable runs without interfering with electromagnetic signals, making them a good fit for telecommunications and sensitive data centers.
- High-voltage area walkways: keep maintenance walkways non-conductive and safe for technicians under all operating conditions.
6.4 Architecture and Construction
- Canopy structures: 75% lighter than steel, allowing large, aesthetically pleasing cantilevered designs that can be installed without heavy-duty lifting equipment.
- Roofing supports: serve as purlins or trusses in environments like indoor swimming pools or industrial warehouses to resist internal moisture and chemical attack.
- Facade elements: compatible with concrete thermal expansion; resistance to thermal bridging improves the energy efficiency of building envelopes.
- Architectural features: can be manufactured in various colors and textures, letting architects combine modern performance with traditional aesthetics in public spaces.
7. Connection Methods
FRP I-beams can be connected using several methods:
| Method | Advantages | Notes |
|---|---|---|
| Bolted (through) | Simple, removable | Use stainless steel bolts |
| Plate connections | Strong, versatile | FRP or steel plates |
| Adhesive bonding | Smooth appearance | Surface prep critical |
| Welding (specialized) | Strong joints | Requires special equipment |
8. Design Considerations
- Deflection limits: typically L/200 for structural members
- Safety factors: 3.0 minimum for permanent loads
- Lateral bracing: provide lateral support to prevent buckling
- Connection design: ensure connections can develop full member strength
- Service environment: select the appropriate resin for chemical exposure
“FRP I-beams represent a real shift in structural design for corrosive environments. The initial material cost premium is consistently offset by reduced maintenance, extended service life, and easier installation — delivering superior lifecycle value.”
Need Custom FRP I-Beams?
Guangdong Haikuo manufactures FRP I-beams:
- Standard sizes: I-100 to I-300
- Custom sizes available
- Polyester, vinyl ester, or epoxy resin
- Various surface finishes
- Technical support for design
Related: FRP Profiles | Equipment | Dies
Browse Products: FRP I-Beam | FRP Channel
Frequently Asked Questions (FAQ)
Q: What’s the maximum span for FRP I-beams?
A: Maximum span depends on beam size and load. As a rough guide: an I-150 can span 4-6m under light loads; an I-250 can span 6-9m. Always verify with structural calculations.
Q: Can FRP I-beams be used outdoors?
A: Yes, with the right resin (vinyl ester recommended) and UV-resistant gelcoat — FRP I-beams suit outdoor applications where corrosion is a concern.
Q: How do FRP I-beams perform in fire?
A: Standard FRP has limited fire resistance. For fire-rated applications, specify phenolic resin or fire-retardant additives; certain formulations char and self-extinguish.
Q: What connections do you recommend?
A: Through-bolted connections with stainless steel fasteners are most common. Use flat washers to distribute load, and design connections to develop full member strength for best performance.
Q: Can you provide engineering calculations?
A: Yes, we can provide preliminary sizing and load tables. For final design, we recommend working with a structural engineer familiar with FRP materials.
