Pultruded I Beam

Pultruded I-beams made from fiber-reinforced polymer (FRP) composites are used as structural members where light weight and corrosion resistance are important. They are common in industrial platforms, walkways, coastal structures, and electrical installations. Here is an overview of pultruded I-beams and their typical uses. Standard sections are listed on our fiberglass H beam and I-beam page.

Manufacturing Process

Pultrusion is a continuous process that produces FRP profiles with a constant cross-section. The steps are:

1. Raw Material Preparation: Continuous fibers (typically glass) are pulled through a resin bath.
2. Shaping: The resin-impregnated fibers are pulled through a heated die shaped like an I-beam.
3. Curing: The resin cures in the die, producing a solid, uniform cross-section.

We manufacture pultruded profiles using pultrusion machines and custom pultrusion dies matched to each profile shape.

Material Composition

Pultruded I-beams typically consist of:

• Reinforcing Fibers: Usually E-glass fibers; carbon fibers can be used for higher stiffness where required.
• Thermosetting Resin Matrix: Polyester, vinyl ester, or epoxy resins selected for the environment.
• Additives: UV inhibitors, flame retardants, and other modifiers as specified by the project.

Key Characteristics

Pultruded I-beams offer several useful properties:

1. Strength-to-Weight Ratio: Lighter than steel for equal cross-sectional dimensions, with good stiffness along the pultrusion direction.
2. Corrosion Resistance: Resists many chemicals and environmental factors better than bare steel.
3. Low Thermal Conductivity: Reduces thermal bridging compared with metal beams.
4. Dimensional Stability: Maintains shape well under typical service loads and environmental changes.
5. Electromagnetic Transparency: Does not interfere with RF signals.
6. Low Maintenance: Does not require painting or galvanizing in many environments.

Mechanical Properties

The mechanical properties of pultruded I-beams depend on fiber type, resin system, fiber fraction, and orientation. Typical ranges vary by grade. Contact us for material data sheets with tensile modulus, density, and flexural properties for the specific profile you need.

Pultruded I-beams are anisotropic, meaning their strength and stiffness are highest along the pultrusion axis and lower in transverse directions. Design calculations should account for this.

Applications

Pultruded I-beams are used in industries such as:

1. Construction: Structural supports for buildings, bridges, and walkways.
2. Industrial: Platforms, supports, and structures in corrosive environments.
3. Marine: Docks, piers, and offshore structures.
4. Electrical: Non-conductive structural components in substations and utility installations.
5. Transportation: Lightweight framing in vehicles and infrastructure.

Design Considerations

1. Shear Deformation: FRP beams can exhibit more shear deformation than steel; include this in deflection calculations.
2. Connection Design: Connections often require bolts, bonding, or specialty fittings rather than welded steel details.
3. Fire Resistance: Flame-retardant resins are available, but additional fire protection may be needed for some applications.
4. UV Exposure: Prolonged sunlight can degrade some resin surfaces; specify UV inhibitors or protective coatings for outdoor use.

Advantages and Limitations

Advantages:

• Lightweight
• Corrosion-resistant
• Good strength-to-weight ratio
• Low maintenance in many environments
• Electrical and thermal insulation

Limitations:

• Higher initial material cost than standard steel or wood in some cases
• Limited standard sizes compared with rolled steel sections
• Potential for UV degradation if not protected
• Lower stiffness than steel, so larger cross-sections may be needed for the same deflection limit

Available I-Beam Sizes

Item		W	H	T	Weight
		mm	mm	mm	kg/m
I Beam		38.5	16.5	4.1	0.50
		120	60	6	2.63
		150	150	9.5	7.87
		152	76	6.35	3.56
		152	76	9.5	5.20
		152	76	10	5.46
		200	100	9.5	6.95
		200	200	10	11.14

Other pultruded profiles, including channels, angles, and tubes, are available to match your structural design.

Frequently Asked Questions

What is a pultruded I-beam?

A pultruded I-beam is a fiberglass-reinforced structural profile made by pulling continuous fibers through a resin bath and heated die. The result is a straight, consistent beam with good corrosion resistance.

What are pultruded I-beams used for?

They are commonly used for platforms, stairways, walkways, roof supports, bridges, sewage plants, marine structures, and other applications where strength and corrosion resistance are important.

How does it compare to steel?

Compared with an equal cross-section, a pultruded I-beam is lighter and does not rust. It can reduce maintenance in corrosive environments, although steel typically has higher stiffness.

Is it suitable for outdoor or wet environments?

Yes. It can be used outdoors, in coastal areas, and in chemically aggressive environments because it resists moisture, salt, and many corrosive substances. Specify UV-stable resin for prolonged sun exposure.

Does it conduct electricity?

No. It is non-conductive, which makes it suitable for electrical installations, utility structures, and areas where electrical isolation is important.

Can it be cut and installed like steel?

It can be cut, drilled, and installed with tools and fasteners designed for composites. Welding is not used for FRP; mechanical fasteners or adhesive connections are typical.

Does it require painting or anti-rust treatment?

It does not rust like steel, and in many environments it does not require painting or galvanizing. UV protection may be needed for long-term outdoor exposure.

Can custom sizes be ordered?

Yes. Custom dimensions, resin systems, and fabrication options are available depending on project requirements.

Conclusion

Pultruded I-beams are a practical choice for structures where corrosion resistance, light weight, and low maintenance are priorities. They are widely used in industrial, marine, and electrical applications and can be specified in a range of sizes and resin systems.