Laminated Rubber Bearing Pad Rectangular Circular PTFE Sliding for Bridges

Laminated rubber bearing pads are support components installed between bridge beams and piers to transfer vertical loads and accommodate horizontal movement. The product is vulcanized from multiple rubber layers and reinforcing steel plates, available in rectangular, circular, and PTFE sliding configurations. Planar dimensions, rubber layer thickness, and steel plate layers are determined based on bridge structural form and displacement requirements. Key points at a glance:

Vertical load capacity comes from steel plates confining the rubber
Horizontal movement is accommodated through shear deformation of rubber layers
PTFE sliding configuration reduces sliding resistance
Rectangular and circular shapes match different pier geometries

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Model:
Customized
Brand:
MingHeng

Internal Structure

The internal structure of a laminated rubber bearing pad is straightforward, but each layer has a clear function. Rubber layers provide elasticity and deformation capacity, forming the basis for the bearing pad's displacement accommodation. Reinforcing steel plates sit between adjacent rubber layers, restraining the lateral bulging of rubber. When vertical load is applied, the rubber tends to bulge outward under compression, and the steel plates prevent this, placing the rubber in a triaxial compression state and increasing vertical stiffness.

The outer rubber layer fully encapsulates all steel plates, preventing direct contact between the plates and external moisture or air. For PTFE sliding bearing pads, an additional polytetrafluoroethylene plate is bonded to the upper surface, creating a low friction sliding interface. A stainless steel plate is installed at the corresponding position on the beam soffit. Together, they significantly reduce horizontal resistance during beam movement.

The difference between rectangular and circular shapes lies mainly in the planar profile. Rectangular bearing pads are easy to align with beam soffit surfaces and pad stone dimensions, while circular bearing pads have consistent deformation characteristics in all horizontal directions, making them suitable for circular piers or locations without directional requirements. The internal construction is the same for both, with differences concentrated in the way planar dimensions are determined.

Performance Behavior

Vertical Load Bearing: With steel plates restraining rubber bulging, the bearing pad achieves high vertical capacity within relatively modest thickness. Compression deformation remains controllable within the design load range.
Horizontal Displacement: Rubber layers deform under shear force with relatively low horizontal stiffness, producing small reaction forces on piers during beam movement.
Rotational Accommodation: When beam ends rotate due to loads or installation slope, rubber layers adjust contact through non uniform compression, reducing localized stress concentration.
Sliding Resistance Reduction: The friction coefficient of the PTFE sliding surface is lower than direct rubber to concrete contact, with greater advantages under large displacement.
Durability Protection: The outer rubber fully encapsulates steel plates. Chloroprene rubber performs stably in coastal and high UV environments.

How to Select

When selecting a laminated rubber bearing pad, first confirm the planar shape required by the bridge structure. Rectangular shapes suit most concrete beams with flat soffits, while circular shapes suit circular pier columns or locations where direction is not critical. Then confirm displacement requirements. If the bridge span is large or the region has significant temperature variation, PTFE sliding configuration should be considered.

For dimensions, planar size is determined by design load and local concrete compressive strength, while thickness is determined by horizontal displacement and rotational requirements. For rubber material, natural rubber is sufficient for conventional inland areas, while chloroprene rubber is recommended for coastal or high UV regions. Steel plate layers are determined by vertical load requirements. Increasing layers improves stiffness but also adds weight and cost.

Custom Production

All laminated rubber bearing pads are produced according to project requirements. Customization requires confirmation of planar shape, dimensions, rubber material, steel plate layers, and surface configuration. Rectangular products require length and width, while circular products require diameter.

Engineering Applications

Beam end support for small to medium span highway bridges
Pier to girder connection nodes in urban viaducts and ramp bridges
Beam end support locations in railway bridges
Beam ends with larger displacement requirements in long span continuous girder bridges
Bridge joint locations in regions with significant temperature variation
Custom matching for bearing replacement projects on existing bridges

Engineering Applications of Bridge Rubber Bearing Pads

Installation and Inspection

Before installation, check the flatness of the pad stone surface and remove dust and oil. Align the bearing pad centerline with the design position during placement to avoid eccentricity. PTFE sliding surfaces should remain clean, and stainless steel plates should be free of scratches or debris. Lower the beam slowly to avoid impact. After completion, check for void or eccentric compression. Routine inspection focuses on abnormal deformation, cracks, or steel plate exposure.