Mechanical Advantage of Catenaries for Different Cable Materials

[EventEngineering]

Hello All

Standard mathematical equations for ascertaining tension within the catenary cable do not take account of the material it is made from.

Steel causes large mechanical advantage, hence the dramatic tension force for low sag. However in the field we have seen that cordage like Dynex & Dyneema, have the opposite effect with very low tension (which is great for your reaction connection!)

So my question:

Does anyone know of a formula which takes these factors (rope material/stretch) into account?

I have a few Uni papers on it but nothing to quickly equate tension in lines.

Cheers Team - hopefully someone has some insight!

Morgan - Structural Engineer

 

[Denial]

Over the course of quite a few years I have gradually developed a spreadsheet to calculate the forces in a single (point-loaded) cable.[ ] When trying to do this I eventually managed to find a method to allow for the stretch in the cable. It was in a paper by an electrical engineer.[ ] See "Precise Sags and Tensions in Multiple Span Transmission Lines", by J. Barrien, Electrical Engineering Transactions, 1975, The Institution of Engineers, Australia.

The author merely gives the method.[ ] He does not derive it, and he does not say where he obtained it.[ ] However before (and after) using it I checked it as far as I could, including against other software, and concluded that its results were "sensible".

If you simply want a tool that will give you the results, my spreadsheet is downloadable from my web site (

http://rmniall.com).

[ ] If you want the actual method, you can get it from Barrien's paper.

 

[EventEngineering]

Legend! Thank you very much.