Bar stock for Bridge Building
iglidur® RN 326 – a newly developed iglidur® material as alternative to your incremental launching bearings
You would be forgiven for not associating huge bridges with igus® but actually you would be wrong! igus® products are everywhere and there is now a material that is being used as an alternative to incremental launching bearings. If like me, you have no idea what an incremental launching bearing is, hopefully this blog will help you understand the fundamentals.
What is incremental launching and how is iglidur® used as an alternative material?
The incremental launching method is a method for building bridge superstructures, preferably used for bridging deep valleys. This method is reminiscent of industrial production; individual roadway elements or concreting sections are manufactured at a point. After one section is finished, it is moved by a hydraulic system and the next section can be started. In order to bridge the first pier, a cantilever is used which allows sliding elements to move concrete sections over the bridge piers. These are also known as incremental launching bearings.
What do these launch bearings do?
Fundamentally, the incremental launching bearings enable displacement, reduces forces and maintains a low coefficient of friction whilst moving the sections. Due to the uneven load distribution and edge loads that can occur during displacement, the material must have a degree of elasticity to prevent breakages.
The bridge between technical improvement and decreasing costs:
In the traditional incremental launching process, PTFE or PE sliding elements constructed of a combination of PTFE, elastomer and a steel plate are often used but these have disadvantages that once the PTFE layer has been worn away, the bearings no longer has any sliding properties, deeming it useless and require replacement.
This is where the new iglidur® RN326 comes into its own. This material has been designed especially for high impact applications, durable with low moisture absorption.
Sliding elements made entirely of iglidur® RN326 material are homogeneous over the entire material thickness and therefore do not lose any of their tribological properties. The iglidur® material also exhibits high strength therefore edge loads do not pose a problem. This is all without requiring reinforcements in steel plates!
With a maximum surface pressure of 38 N/mm², the material can withstand considerably higher loads compared to PTFE and yet the material remains highly wear resistant. The factors mentioned above increase the service life of the plates, which means that the need for sliding elements can be reduced increasing sustainability.
This material is very new to igus® and is being successfully tested on bridges in Germany.
It won’t be long until the UK starts to implement decisions, whereby they change materials that wear easily and require regular replacement for materials which help keep technology up and long-term costs down.