March 8, 2026
When specifying structural bearings for a new bridge or a rehabilitation project, the choice between elastomeric bearings and pot bearings is one of the most consequential decisions an engineer will make. Both bearing types are widely used across highway bridges, railway viaducts, and pedestrian structures worldwide, yet they differ fundamentally in their mechanical behaviour, load-carrying capacity, and long-term maintenance requirements. This article provides a rigorous technical comparison to guide engineers, procurement managers, and project owners toward the most appropriate selection for their specific application.
An elastomeric bearing — also known as a laminated elastomeric bearing pad or steel-reinforced elastomeric bearing — consists of alternating layers of natural or neoprene rubber bonded to internal steel reinforcing plates under high pressure and heat. This composite construction gives the bearing its remarkable ability to accommodate both vertical loads and horizontal movements simultaneously, through the shear deformation of the rubber layers.
The key technical advantage of elastomeric bearings is their simplicity. They contain no moving parts, require no lubrication, and are highly resistant to corrosion and environmental degradation. Standard laminated elastomeric bearings can accommodate rotations of up to 0.02 radians and horizontal displacements of ±50 mm, making them ideal for short to medium span bridges (typically up to 60 metres) with moderate movement demands. Their low initial cost and near-zero maintenance requirements over a 50-year design life make them the most economical choice for the vast majority of highway bridge applications.
However, elastomeric bearings have well-defined limitations. Under very high vertical loads — typically exceeding 5,000 kN — the required plan dimensions become impractically large. Similarly, when the design calls for large rotations combined with high vertical loads, the rubber layers may be subjected to tensile stress, which is detrimental to long-term performance.
Left: Laminated elastomeric bearing pad (natural rubber with steel shim plates). Right: Circular pot bearing with PTFE sliding disc. Both are standard bridge bearing types supplied by Bridgent.
A pot bearing consists of a circular steel cylinder (the "pot") containing a disc of unreinforced elastomeric material (the "piston"), which is confined under pressure by the pot walls. This confinement allows the rubber to behave as a near-incompressible fluid, enabling the bearing to carry very high vertical loads — routinely exceeding 50,000 kN — while accommodating rotation through the deformation of the confined rubber disc.
Pot bearings are available in three configurations: fixed (no horizontal movement), free-sliding (movement in all horizontal directions via a PTFE/stainless steel sliding interface), and guided (movement in one direction only). This flexibility makes them the preferred choice for long-span bridges, cable-stayed structures, and railway bridges where precise control of structural movement is essential.
The principal disadvantage of pot bearings is their complexity and associated maintenance requirements. The PTFE sliding surface will wear over time and requires periodic inspection and eventual replacement. Dust seals must be maintained to prevent contamination of the sliding interface.
| Parameter | Elastomeric Bearing | Pot Bearing |
|---|---|---|
| Vertical Load Capacity | Up to ~5,000 kN | 500 kN to >100,000 kN |
| Horizontal Movement | ±10 mm to ±50 mm (shear) | ±50 mm to ±500 mm (sliding) |
| Rotation Capacity | Up to 0.02 rad | Up to 0.03 rad |
| Moving Parts | None | PTFE sliding disc, dust seal |
| Maintenance | Minimal (visual inspection) | Periodic PTFE replacement |
| Design Life | 50+ years (typical) | 25–50 years (PTFE dependent) |
| Applicable Standards | EN 1337-3, AASHTO LRFD | EN 1337-5, AASHTO LRFD |
| Typical Applications | Short/medium span highway bridges | Long-span, railway, cable-stayed |
| Relative Cost | Low | Medium to High |
Cross-section comparison: The elastomeric bearing (left) accommodates movement through rubber shear deformation. The pot bearing (right) uses a confined rubber disc for rotation and a PTFE sliding surface for horizontal movement.
The decision framework is relatively straightforward. For highway bridges with spans up to 60 metres and moderate traffic loads, laminated elastomeric bearings offer the best combination of performance, durability, and economy. For long-span bridges, railway structures, or any application where vertical loads exceed 5,000 kN or movements exceed ±50 mm, pot bearings are the appropriate choice.
It is also worth considering hybrid solutions. On a continuous multi-span bridge, elastomeric bearings may be entirely appropriate for the intermediate piers, while pot bearings are specified at the abutments and expansion piers where movements are greatest.
Bridgent supplies both elastomeric and pot bearings manufactured to EN 1337 and AASHTO standards, with full factory acceptance testing documentation. Our technical team is available to assist with bearing schedule preparation and load/movement calculations for any bridge project worldwide.
Our engineering team provides free technical consultation for bearing selection, schedule preparation, and compliance with international standards.
Tags: Bridge Engineering Bridge Bearings Bridge Construction Bridge Maintenance Bridgent Products
Our engineering team provides free technical consultation for bearing selection, schedule preparation, and compliance with international standards.
Westcoast New Area, Qingdao City ,Shandong Province ,China
