wire rope area 3

[structSU10]

Does anyone have a reference that states the area of different wire ropes? I am looking at a 1x19 or 7x19 stainless steel cables at 1/4" diameter. I only find in my searches a max breaking strength and a weight per 100 ft. I could back figure the area based on the weight but I would still be relying on a guess to the unit weight of the steel that could make a bit of a difference.

 

[JStephen]

Along with the area, you need the apparent modulus of elasticity, which includes some geometrical factors rather than just the material.
Googling just now, I see some where they assume area equal to a round rod of that diameter, others where it varies depending on construction.
In either case, the manufacturer would have the apparent E, and you'd use the area for which E was tabulated.

 

[phamENG]

I have found this to be a useful resource:

Wire Rope User's Handbook

 

[BAretired]

If you need modulus of elasticity, you won't get it with wire rope. You'll have to go to prestressing tendons.

For Wire Rope:

BA

 

[BridgeSmith]

I would still be relying on a guess to the unit weight of the steel that could make a bit of a difference.

If you're looking for the actual cross-sectional area, using 490 pcf as the density of steel will easily get you within 2%.

Rod Smith, P.E., The artist formerly known as HotRod10

 

[Lomarandil]

I will also vouch for the info provided above.

For typical 6x19 wire rope, the apparent modulus E is usually just over half the material value, allowing for geometric elongation.

----
just call me Lo.

 

[structSU10]

To clarify what I am doing - I am looking at an exterior cable guard rail. I want to check the cable for deflection plus temperature swings effect on the cable. I have an example calculation for each for smaller cable than what is proposed, so A & E are important values to have for these calculations.

All cable rail manufacturer's sites don't seem to have the information either, and I come up dry looking at controlling ASTMs.

 

[Howlyn2]

ASTM A475 Standard Specification for Zinc-Coated Steel Wire Strand specifies the Nominal Diameter of Coated Wires in Strand and the Number of Wires in Strand for typical strand diameters in Table 1 - Physical Properties of Zinc-Coated Steel Wire Strand. You can back in to the total area using the summation of the individual areas. From there you can calculate breaking strengths as needed pending you know your yield stresses.

 

[BridgeSmith]

The area is easy to get. As I said, you can get plenty close enough by using the typical density of steel.

As others have said, the modulus of elasticity of the steel itself is a minor factor in the elongation of the cable subjected to tension force. However, it's about 29,000 ksi, maybe slightly lower, but that minor variation is well within the margin of error for the total effective elongation 'modulus' of the cable.

Rod Smith, P.E., The artist formerly known as HotRod10

 

[JedClampett]

File this (Wire Rope) under the billion things I thought were easy, but are not. Here's a reference, which might be different than the one above.

 

[BAretired]

Page 30 of Jed's reference comments on modulus of elasticity:

BA

 

[Ingenuity]

When the cables for the George Washington Bridge were being researched and developed by John A. Roebling & Sons Company (in late 1920's) - under the leadership of Charles Sunderland - they quickly realized that they would not be able to fabricate very long ropes to accurate lengths with accurate prediction of their tension-elongation behavior using current rope making methods.

When the working load on a rope exceed the tension used during manufacture of the rope, the rope compacted further and inelastic axial deformations occurred.

Sunderland therefore 'prestretched' his ropes to a tension load that exceeded their design working loads. The "Kinkora Prestretcher" was constructed near Roebling, NJ. It was able to prestretch ropes of length greater than 3,000 feet. It was a huge machine!