Tetron Spherical Bearings S3
FREYSSINET – SPHERICAL ‘S3’
Bearings are advanced and sophisticated support components, offering complete structural freedom in terms of rotation and horizontal sliding.
All Freyssinet bearings are manufactured in accordance with BS 5400: Section 9.2:1983.
Material specifications
Tetron ‘S3’ bases and rockers use maintenance-free aluminium alloy.
Sliding plates are made of structural steel, faced with high quality stainless steel.
Sliding surfaces are lined with pure PTFE according to BS 6564.
Pins for side restraints are made by special spring steel with minimum yield strength 1100 N/mm².
All permanently exposed steel parts are fully corrosion protected. Several different treatments are available, full technical data on request.
Full details of material specifications are available on request.
Design
Sliding friction
The friction coefficient for PTFE decreases with increasing direct stress. Tetron bearings are permanently lubricated to reduce the static coefficient of friction.
Lateral restraint
It is emphasised that only one S3F bearing at a support should be provided to resist a full transverse force, because it is not possible to position two bearings in a rigid structure to guarantee that such a force will be shared equally between them. Also, adequate vertical load must be present to ensure stability. We recommend consultation by our Engineer.
High rotation
± 3° (0.052 radians) in any plane. More than adequate for most structural purposes.
Removability
All bearings are designed to be removable with minimum jacking of the structure.
Contact stress
The average base contact stress of the bearings illustrated approaches 17.5N/mm2. Direct contact between the aluminium parts of the bearings and dissimilar metals must be avoided.
