What is a Slide Bearing?

Understanding Slide Bearings in Structural Engineering

In the world of structural engineering, one of the most common challenges is dealing with the movement of structures. This movement can occur due to various factors such as thermal expansion, seismic activity, or differential settlement forces. If not properly accounted for, such movements can lead to stress build-up, structural damage, and even failure over time. To counteract these forces and ensure the longevity and stability of structures, engineers incorporate slide bearings into their designs.

What Are Slide Bearings?

Slide bearings are specially designed components that allow controlled movement within a structure, reducing friction and stress caused by external forces. They are crucial in applications where high loads and low-speed movements occur, such as bridges, industrial plants, pipelines, and large buildings.

One of the most effective materials used in slide bearings is Polytetrafluoroethylene (PTFE). This material is highly valued for its self-lubricating properties, durability, and ability to function effectively under extreme conditions. PTFE slide bearings operate best at high loads and low speeds, which is when their self-lubricating characteristics perform at their peak.

How Do Slide Bearings Work?

The basic design of a slide bearing consists of two surfaces that slide against each other, minimising friction while allowing the necessary movement. The standard configuration includes two pads of PTFE sliding against each other, ensuring smooth displacement. However, in cases involving extremely high pressures, a single PTFE pad is used in conjunction with a polished stainless-steel plate. The polished surface enhances smooth movement while providing additional strength and wear resistance.

A crucial design aspect of slide bearings is ensuring continuous contact between the bearing pads. To achieve this, the top pad is typically larger than the bottom pad. This difference in size is greater than the expected movement of the structure, ensuring that the two components remain in contact throughout any shifts, preventing misalignment and reducing wear.

The slide bearing components can be fixed to the installation by bolting, tack-welding, full welding, or mortar embedment, and the appropriate type of bearing should be chosen according to the installation method.

Key Benefits of Slide Bearings

Reduced Friction and Wear: The use of PTFE in slide bearings significantly lowers friction, ensuring smooth movement while reducing the risk of wear and tear over time.

Load-Bearing Capacity: Slide bearings are designed to handle extremely high loads, making them suitable for heavy-duty applications such as bridges and industrial machinery.

Improved Structural Longevity: By allowing controlled movement and reducing stress, slide bearings contribute to the overall durability and lifespan of structures.

Maintenance-Free Operation: PTFE's self-lubricating properties eliminate the need for additional lubrication, reducing maintenance costs and effort.

Corrosion Resistance: PTFE and stainless-steel components are highly resistant to environmental factors, making slide bearings ideal for use in harsh conditions.

Benefits of using Fluorinoid® materials for slide bearings:

• The lowest coefficient of friction of any known solid ‘engineering material’ including lubricated metal
• No Stick-slip action
• Fluoroglide® Bearings have a near-infinite life since chemicals and weather do not affect PTFE
• No maintenance required
• Fluorinoid® PTFE will never cold weld to itself
• Fluoroglide® Bearings are easily installed on-site
• Fluoroglide® PTFE Bearings are less bulky than alternative assemblies
• There is no possibility of fatigue failure
• Small particles which may become embedded do not cause any binding of the surfaces
• Fluoroglide® Bearings can accommodate some misalignment in construction.

Applications of Slide Bearings

Slide bearings are widely used in various industries, including:

BRIDGES AND OVERPASSES

To accommodate expansion and contraction due to temperature fluctuations.

INDUSTRIAL AND POWER PLANTS

Where heavy machinery requires controlled movement to absorb vibrations and dynamic forces.

PIPELINES

To compensate for thermal expansion and ground settlement.

HIGH-RISE BUILDINGS

Where structural flexibility is necessary to withstand wind loads and seismic activity.

SUBSEA PUMPING STATION

To reduce friction between the pump shaft and the stationary housing, enabling smooth rotation and extending pump lifespan. 

Conclusion 

Slide bearings are an essential component in modern structural engineering, providing a simple yet highly effective solution for managing movement and reducing stress in large structures. With the use of high-performance materials such as PTFE, these bearings offer exceptional durability, low maintenance, and optimal performance under extreme conditions. By incorporating slide bearings into structural designs, engineers can enhance safety, reliability, and longevity, ensuring that structures remain stable and functional for decades to come.

To find out how we can support your projects, contact info@fluorocarbon.co.uk