Cable Suspension Bridge - Support of Continuious Cable at top of Tower

[CBEngi]

I'm currently working on a suspension bridge where the main cable will go over the top of the tower, then continue down to the rock anchor foundation, in once continuous piece.

I have previously completed work where cable size was critical compared to sheave diameter (d/D ratio) to ensure stress in the outer fibers of the cable was not exceeded.

My question really is since the cable is no longer bent at a 90 degree angle (Actually closer to 30). Is this still a major issue with ensuring cable life span. I would like any reference material for the reduced angle anyone might know of.

I'm looking to accomplish something like the link below, but with a much smaller cable (2 1/2" Diameter) i'm wondering how complicated this assembly will need to be.

http://www.wsdot.wa.gov/TNBhistory/Machine/photos/M2-7-cable-saddle-drawing_l.jpg

Does anyone have any experience or reference tables for this application?

 

[KootK]

I'm no expert in this area but I don't feel that the reduced angle changes anything. It's curvature that stresses your cable and the curvature is the same at 30 degrees as it would be at 90 degrees.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[btrueblood]

Contact the manufacturer of the cable for their recommendations for the bend radius. It will be different for various cable wire layups and core materials, etc. One positive is that (unless you are planning to recreate the original Tacoma Narrows Bridge) the cable will not (like with sheaves/pulleys) undergo repetitive dynamic bending/straightening.