Structural Design of Cable and Steel Posts Holding the Cables

[M.IDR]

Hello,
Cables are suspended between two steel posts and anchored as shown in the picture. How these Cable needs to be designed and What are the main components provided in the structural design drawings for construction.

3D View.

Does any one have slightest idea?

 

[BridgeSmith]

I have applied 30 lb/ft wind loads on the posts but my FEM software does not apply wind load to cables do you think that is necessary as well?

Most definitely the wind load must be applied to the cables. We typically ignore the wind on the poles as being negligible (Typically less than 2% of the total forces on the pole).




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

 

[BridgeSmith]

Insofar as wind design, the structure should be capable of resisting expected maximum wind loads when unloaded, but it seems unlikely it would be loaded with personnel during a 90 mph wind.

Agreed. Calculating the loads separately, I got about the same forces/tension with a 90mph wind on one cable as with a 300lb point load on a cable, which about doubled the tension from the selfweight alone.

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

 

[M.IDR]

BridgeSmith , BAretired

I have applied wind load on each node of the cables as shown does it seem ok to you.?

 

[BridgeSmith]

I don't know the ASCE, so I can't say if your factors are correct for that. I can say that the loading is about half what I get from the AASHTO Sign spec. for a 100mph wind. The primary difference, I think, is in the gust factor (G?), where we use a 1.3 factor applied to the wind velocity, which then gets squared in calculating the wind pressure. AASHTO design would use a 90mph wind, though, except in hurricane-prone areas, which comes out to be about 60 lbs at each node. I'm not saying you're wrong, just telling you what I got for comparison of the loading on the cables and poles. I get your wind loading at a design wind speed of 68 mph (88mph gust). The cable tension is about 5500 lbs under self weight + that wind load.

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

 

[dik]

plus ice and added wind?

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[BridgeSmith]

plus ice and added wind?

We don't consider ice, since the max wind load is always much larger, and we assume that the ice is not going to stay on a cable in high winds.

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

 

[Denial]

The man on the left seems to be deflecting his cable considerably more than the guy on the right

The photo certainly seems to show this, but it could be because he has only just "launched" and so his tether tension is higher because it has to decelerate him vertically.

 

[dik]

Including the ice build up... area can be increased 3x or more...

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[BridgeSmith]

Including the ice build up... area can be increased 3x or more...

We don't get that kind of ice buildup here in Wyoming, but even if we did, a 30mph wind would shake it off of the cables (and traffic signals, which is what our span wires support). For us, the max wind produces a load on the order of 5 times the dead load. Years ago when I started designing span wire signal structures, I looked at the loading combinations for what we do, and determined that the DL + Ice + 0.5Wind combination was always less critical than DL + 1.0Wind for our span wires and what we put on them.

I think the OP said ice wasn't a consideration for the location, anyway, so for this case it's a moot point.

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