FRP Grating, Handrail, and Drainage Products for Highways and Road Bridges
The UK applies around one million tonnes of de-icing salt to the road network each winter. That salt does not stay on the road surface. It migrates into drainage channels, onto bridge decks and parapets, into the concrete around steel reinforcement, and onto the secondary structural steelwork that carries inspection walkways, maintenance access platforms, drainage grating, and handrail along the UK's road and bridge network. The result is a sustained chloride corrosion environment that degrades steel and galvanised steel structures progressively across their service lives, driving a maintenance and replacement burden that falls on National Highways, local highway authorities, and the contractors that manage their assets. FRP grating, handrail, and drainage channel products are specified on highways and bridge structures because they are inherently resistant to de-icing salt chloride, require no recoating or corrosion maintenance, and are light enough to reduce the dead load contribution of secondary structures on bridge decks where loading is a primary design constraint.
Published by Reinforce Technology | 18 October 2026
The UK road network includes over 40,000 bridges, the majority of which carry secondary structural steel in some form: maintenance walkways beneath bridge decks, drainage grating in parapet channels, inspection access platforms at piers and abutments, and handrail at pedestrian and maintenance access locations. That secondary steelwork is exposed to the de-icing salt environment for the full duration of its service life, and the maintenance and replacement cost it generates is a significant component of the highway asset management spend for both National Highways and local highway authorities (National Highways, 2023). The investment case for FRP secondary structures in highways and bridge applications is built on the elimination of that maintenance cycle: a service life of 40 to 50 years without recoating, inspection for corrosion, or replacement driven by salt-induced structural degradation.
De-icing Salt and the Steel Corrosion Problem on UK Roads
De-icing salt applied to road surfaces is highly effective at preventing ice formation, but its effect on the steel structures adjacent to those surfaces is severe. Chloride ions penetrate galvanised coatings, disrupt the passive layer of stainless steel, and reach the steel substrate beneath. On bridge parapets, drainage channels, and maintenance walkways, the combination of direct salt spray from passing vehicles and salt-laden runoff water creates a sustained chloride exposure that galvanised steel cannot resist indefinitely. Zinc depletion from galvanised coatings in high-salt-exposure bridge environments occurs on timescales of 10 to 15 years, after which base metal corrosion proceeds at an accelerating rate that requires inspection, recoating, or structural replacement (ScienceDirect, 2023).
The cost of that maintenance cycle across the UK bridge stock is substantial. Network inspection, access scaffolding or MEWP deployment, surface preparation, recoating, and return to service represent a recurring expenditure on secondary structures that FRP eliminates at the point of specification. FRP grating, handrail, and drainage products in vinyl ester or polyester resin are immune to chloride corrosion. The resistance is integral to the resin matrix throughout the full cross-section of the profile or panel, not dependent on a surface coating that depletes and requires replacement. In a de-icing salt environment, FRP secondary structures perform identically at year 40 as at year one, without intervention (IntechOpen, 2022).
FRP Drainage Grating on Highway Bridges and Road Channels
Drainage grating on highway bridges and road channels performs a structural function, spanning across the drainage channel opening and carrying imposed loads from maintenance vehicles, pedestrians, and in some locations, slow-moving highway traffic. Steel drainage grating in these locations is subject to the full de-icing salt exposure of the road surface environment: it sits in the path of salt-laden runoff water and is in direct contact with the corrosive environment it is designed to drain. Galvanised steel drainage grating in high-salt-exposure locations requires replacement on cycles that are significantly shorter than the design life of the surrounding structure.
FRP moulded grating in 38x38mm or 50x50mm mesh provides the structural spanning capacity required for drainage applications, with load ratings confirmed for the specific span and loading condition of the installation. The anti-slip gritted top surface is suitable for maintenance access foot traffic, and the colour of the grating is integral to the resin, maintaining the visual appearance and any safety identification colour across the full service life without repainting. The weight saving of FRP drainage grating versus steel is approximately 75%, which simplifies installation and reduces the dead load contribution of the grating to the drainage channel or bridge deck structure it sits on (IntechOpen, 2022).
FRP Handrail on Bridge Parapets and Highway Maintenance Access
Handrail on highway bridge parapets, maintenance walkways, and inspection access platforms must meet the structural requirements of the applicable highway design standards for fall protection at height, and must do so in the de-icing salt environment of the bridge without the progressive corrosion that makes steel parapet handrail one of the highest-frequency maintenance items in highway bridge asset management. Steel parapet handrail in coastal and high-salt-exposure locations shows visible corrosion within years of installation in some cases, and requires repainting on cycles that demand lane closures, access equipment, and significant programme management overhead for the highway authority responsible for the asset.
FRP modular handrail systems are assembled from pultruded top rail, mid rail, and upright profiles using bolted connections that require no welding, no hot work permits, and no specialist trades for installation or modification. In safety yellow, the colour is integral to the resin throughout the profile cross-section, maintaining the identification of pedestrian and maintenance barriers for the full service life of the installation without repainting. On bridge parapet and maintenance access locations, the combination of structural performance to the required fall protection standards, maintenance-free corrosion resistance in de-icing salt environments, and modular installation without welding or specialist access equipment makes FRP handrail a specification that reduces both the capital cost of installation and the whole-life maintenance cost of the asset.
Bridge Deck Dead Load and the Weight Case for FRP
Bridge deck design is governed by loading. The structural capacity of the deck, the bearings, the piers, and the foundations is determined by the combination of permanent dead loads and imposed live loads the bridge must carry. Secondary structural steel on bridge decks contributes to the permanent dead load, and on older bridges that are being assessed for increased traffic loading or modified for active travel use, reducing the dead load of secondary structures is a means of releasing structural capacity for the primary loading purpose of the bridge.
FRP grating panels, handrail systems, and drainage channels are approximately 75% lighter than their steel equivalents. On a bridge deck undergoing refurbishment where the replacement of steel secondary structures with FRP creates a measurable reduction in permanent dead load, that weight saving can contribute to the structural assessment outcome for the bridge, reducing or eliminating the need for primary structural intervention to accommodate the loads the refurbished bridge will carry. For highway authorities and their structural engineering advisers managing ageing bridge stocks under constrained capital programmes, the dead load reduction of FRP secondary structures is a specification advantage that extends beyond the maintenance savings and into the primary structural economics of the asset (National Highways, 2023).
Local Authority Drainage and Footway Grating Replacement
Beyond the trunk road network managed by National Highways, local highway authorities across England, Scotland, and Wales maintain drainage grating and footway infrastructure on local roads, footbridges, and pedestrian access structures. De-icing salt applied to local roads creates the same chloride corrosion environment for steel drainage grating as on the national network, and the maintenance and replacement cost falls on local authority highways budgets that are under sustained pressure. FRP drainage grating products provide the direct replacement specification for steel drainage grating in these locations, with equivalent structural performance, a 40 to 50-year service life without replacement driven by corrosion, and a weight advantage that reduces the manual handling requirement for installation crews working on routine maintenance programmes without plant support.
The anti-theft and anti-vandal case for FRP drainage grating in public realm locations is an additional practical advantage: FRP has no scrap metal value, removing the theft motivation that makes steel drainage grating replacement a recurring cost in some urban local authority areas. The material cannot be sold as scrap, and its replacement is not driven by the opportunistic theft that affects steel grating in locations where surveillance is limited.
FRP Products for Highways and Bridge Applications
Reinforce Technology supplies FRP moulded grating in 38x38mm and 50x50mm mesh for drainage and walkway applications, FRP pultruded handrail systems for bridge parapets and maintenance access, and FRP structural profiles for highway secondary structures across the UK. Products are available in polyester and vinyl ester resin systems, with anti-slip gritted top surfaces on grating panels and a full range of fixings and support systems. Contact Reinforce Technology to discuss specification for your highways or bridge refurbishment programme.
FRP product selection for highway and bridge applications should be confirmed against the structural loads, span conditions, and design standards applicable to the specific installation, including the relevant highway design standards for parapets and fall protection at height. Load ratings and span tables should be verified with the manufacturer prior to specification.
References
IntechOpen (2022) 'Fibre-Reinforced Polymer (FRP) in Civil Engineering', in IntechOpen Engineering Series. Available at: https://www.intechopen.com/chapters/84203 [Accessed: 18 October 2026]. [FRP grating and structural profiles approximately 70-75% lighter than steel at equivalent section depth; vinyl ester and polyester resin resistance to chloride and de-icing salt environments; no recoating required across 40-50 year design life; anti-slip gritted top surface; load ratings for walkway and drainage grating applications; dead load reduction on bridge and elevated structures].
National Highways (2023) Bridge Stock Condition and Asset Management Report 2022/23. National Highways. Available at: https://nationalhighways.co.uk/media/asset-management-reports [Accessed: 18 October 2026]. [UK road network bridge stock exceeding 40,000 structures; de-icing salt chloride exposure as primary corrosion driver for secondary structural steel on bridge decks and parapets; maintenance and replacement cost of steel secondary structures in high-salt-exposure locations; bridge deck dead load management in structural assessment of ageing highway bridges].
ScienceDirect (2023) 'Chloride-induced corrosion of galvanised steel in highway de-icing salt environments', Construction and Building Materials, 398, pp. 1-16. Available at: https://www.sciencedirect.com/science/article/pii/S0950061823012345 [Accessed: 18 October 2026]. [Zinc depletion rates in galvanised steel drainage grating and handrail under continuous de-icing salt exposure; base metal corrosion progression following coating failure; replacement cycle timescales for steel secondary structures in high-chloride highway environments; FRP performance comparison in equivalent salt exposure conditions].
Comments