Pultruded FRP grating carries high loads over long spans because of continuous glass reinforcement; sizing uses the load table for the bearing-bar height and span you need.
- Best for: high-load, long-span industrial walkways
- Choose pultruded for: spans and loads beyond molded limits
- Key spec: ISO 9001, load table per bar height/span
1. What Is FRP Pultruded Grating?
FRP pultruded grating (also called pultruded fiberglass grating or GRP pultruded grating) is manufactured by pulling continuous glass fiber rovings through a resin bath and then through a heated steel die that cures the resin into a constant cross-section. Unlike molded grating which has bidirectional strength, pultruded grating delivers exceptional unidirectional strength along the bearing bar direction, making it ideal for long spans and heavy loads. Common profiles include I-bar, T-bar, and rectangular tube bars in depths from 25mm to 100mm.
2. I-Bar vs T-Bar: Which Profile?
I-bar (standard): The most common pultruded grating profile. Provides excellent strength-to-weight ratio with lower material cost. Recommended for most industrial walkways, platforms, and solar PV access paths. T-bar: Has a wider top flange (38-50mm) for improved wear resistance and anti-slip surface. Choose T-bar for high-traffic areas, stair treads, and areas with frequent rolling loads (trolleys, pallet jacks). Bar depths: 25mm (light duty), 38mm (medium duty), 50mm (standard heavy duty), 65mm (extra heavy, forklift rated), 100mm (extra long span).
3. Load Capacity Table (50mm I-Bar, 38mm Bar Spacing)
Span 600mm: Uniform load 45 kN/m², point load 8.0 kN, deflection L/240. Span 1000mm: Uniform load 25 kN/m², point load 5.0 kN. Span 1500mm: Uniform load 12 kN/m², point load 3.0 kN. Span 2000mm: Uniform load 7 kN/m², point load 2.0 kN. Span 2500mm: Uniform load 4.5 kN/m², point load 1.5 kN. For 65mm I-bar: at 1000mm span, uniform load reaches 45 kN/m² with 3-ton forklift rating. Always specify span measured between supports along bearing bars — pultruded grating strength is directional.
4. Deflection Limits & User Comfort
For industrial floors, L/200 deflection limit is standard (e.g., 5mm at 1000mm span). For office areas or sensitive equipment, use L/240 (4mm at 1000mm). For public spaces and premium feel, L/300 (3.3mm at 1000mm). Excessive deflection causes user discomfort and perceived instability even when structurally safe. For dynamic loads (walking, forklifts), multiply static load by 1.5 for impact factor. ZEALL provides free structural calculations with every quotation — send us your span and load requirements for a certified design.
5. When to Choose Pultruded Over Molded Grating
Choose pultruded FRP grating when: span exceeds 1200mm (molded grating max practical span), forklift or heavy vehicle traffic, high load capacity needed (>10 kN/m²), long-span bridges and walkways, offshore platforms requiring minimum deflection, or large industrial structures where weight matters. Choose molded grating for: standard walkways (600-1000mm spans), corrosive chemical environments (bidirectional corrosion resistance), irregular openings that require on-site cutting, and applications where both axes see load.
6. Resin Selection for Pultruded Grating
Isophthalic polyester: General corrosion, wastewater, food/pharma. Most economical. Vinyl ester: Strong acids, alkalis, marine salt spray. Best for chemical plants and offshore. Phenolic: Fire-retardant V-0, high-temperature environments. Offshore, mining, underground. Always specify UV-stabilized resin for outdoor applications. For marine/coastal, require SS316 clips — never galvanized steel in salt spray zones.
7. Request a Pultruded Grating Quote
ZEALL GRATING manufactures pultruded FRP grating in I-bar and T-bar profiles, 25-100mm depth, polyester/vinyl ester/phenolic resins. Factory direct pricing from our 20,000m² ISO 9001 facility in Nantong, China. Export to 40+ countries. Send your drawing or specifications for a free engineered quotation within 24 hours.
Design Standards & Data Basis
All load, span and capacity values in this article are typical/indicative, derived from laboratory tests per NAAMM MBG-01 (FRP Grating Design Manual) methodology. Molded grating values apply a 5:1 factor of safety on ultimate capacity; pultruded grating values apply a 3:1 factor of safety, both measured at static ambient conditions. Impact loads are limited to 50% of stated values; long-term loads require creep adjustment per ASCE Structural Plastics Design Manual. Certified load tables, stamped engineering calculations and third-party test reports are available on request.
For structural sizing of your specific application, contact our engineering team with your load requirements, span and environmental conditions — we provide free structural calculations within 24 hours. Browse our molded grating and pultruded grating product pages for full specifications and resin options.
Typical Allowable Uniform Load (kN/m²) - Pultruded I-bar Grating
| Model | Span 1000 mm | Span 1500 mm | Span 2000 mm | Span 2500 mm |
|---|---|---|---|---|
| FG-P5038 (50 mm I-bar x 38 mm spacing) | 22-28 | 10-14 | 5.5-7.5 | 3.5-5.0 |
| FG-P6538 (65 mm I-bar x 38 mm spacing) | 40-50 | 20-26 | 11-15 | 7-10 |
Unidirectional strength measured along bearing bars; spans must be taken between supports along the bar direction. Typical/indicative per NAAMM MBG-01; certified table on request.
Model Naming: Thickness x Mesh Reference
ZEALL molded FRP grating is designated by panel thickness x mesh opening. The standard catalog covers four depths (25 / 30 / 38 / 50 mm) and three mesh sizes (38x38, 19x19, 50x50 mm). A typical designation is "38 mm Molded Grating x 38x38 mm mesh" (model code FG-M3838). Common references:
| Model code | Thickness | Mesh | Duty class | Typical use |
|---|---|---|---|---|
| FG-M2538 | 25 mm | 38x38 mm | Light | Drainage covers, light walkways |
| FG-M3038 | 30 mm | 38x38 mm | Medium | General walkways, ramps |
| FG-M3838 | 38 mm | 38x38 mm | Standard | Industrial platforms, standard service |
| FG-M3819 | 38 mm | 19x19 mm | Standard mini-mesh | Tool handling, heel-safe walkways |
| FG-M5038 | 50 mm | 38x38 mm | Heavy | Forklift areas, long spans |
| FG-P5038 | 50 mm I-bar | 38 mm bar spacing | Heavy pultruded | Heavy-duty platforms, truck traffic |
Typical Structural Parameters (I / S / E)
The table below gives typical flexural stiffness ranges for FRP grating profiles. Values are typical per NAAMM MBG-01 and are not a substitute for a certified mill test report. E depends on resin system (isophthalic polyester approx. 10-12 GPa; vinyl ester approx. 12-15 GPa); I and S scale with bar depth and profile shape.
| Profile | E flexural (GPa) | I (cm⁴ / m width) | S (cm³ / m width) |
|---|---|---|---|
| 25 mm molded grid | 10-12 | 2.5-4.0 | 2.0-3.2 |
| 30 mm molded grid | 10-12 | 4.5-7.0 | 3.2-4.8 |
| 38 mm molded grid | 11-13 | 8-13 | 5.0-7.5 |
| 50 mm molded grid | 11-14 | 16-26 | 8.5-13 |
| 50 mm I-bar pultruded | 12-15 | 55-85 | 22-32 |
Typical values per NAAMM MBG-01; certified values per project-specific mill test report on request.
Browse our product pages for full specifications: FRP pultruded grating.
Frequently Asked Questions
FRP (Fiberglass Reinforced Plastic) grating is a molded or pultruded fiberglass composite grid used for corrosion-resistant walkways, platforms and floorings. It combines glass fiber reinforcement with thermoset resin (polyester, vinyl ester, epoxy) for superior strength-to-weight ratio, zero rust and 20+ year service life.
