Like other structures, pipelines are subject to outside forces and movements, but they may also be subject to interior pressure changes that can cause movements. The expansion and contraction of pipelines, pipes and ducting can be brought about by several causes, and these can lead to substantial linear movement. This, in turn, may give rise to substantial and often dangerous stresses at the pipeline’s supports. For this reason pipeline bearings must be designed in such a way as to minimise stresses. Movement in a pipeline may be caused by:

• Thermal expansion and contraction
• Permanent creep and shrinkage
• Post tensioning strain
• Live load deflections
• Earth movement
• Internal pressure changes within the pipeline
• Internal temperature changes within the pipeline

Pipeline bearings provide a way of supporting pipelines and ducting while at the same time offering little or extremely small resistance to any movement. This is due to the extremely low friction qualities of Glacier DU dry bearing material. Glacier DU© material is a composite material comprising a steel backing strip clad with a porous sintered copper-lead layer which is impregnated with a PTFE mixture.

It is essential for consistent support to be achieved and so there are several different methods of attaching pipeline bearings to pipelines. If it is necessary to use multiple bearings at one support then the design of the structure is such that all sliding surfaces are parallel. If necessary the design can incorporate crosswise or vertical constraint at the pipeline bearing supports in accordance with the customer’s specifications. Call us at +27 (0) 11 605 2434 for any further information regarding pipeline bearings of any type.