Overhead Conduit Support

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bcorbin

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I'm doing a long run of fiber in 1" conduit across an industrial complex. I have managed to route it on existing structure almost all of the way, but I need to span a distance of about 35'-40' between two roof tops. (Below grade is a no-go, the water table is very high, so the owner wants it overhead. Plus, they would have to saw-cut a bunch of pavement.) I am no structural engineer, so I am pretty cautious about just bolting some triangular truss across the gap to mount the conduit to. Any suggestions?
 
thats a long span without getting some engineering help IMO.

there may be some pre-enegineered applications that are on point available from unistrut.
 
If you used RMC you could go 12' between supports.
35'-40' Nope. You would need to add some structural support to span between the buildings.
There is also the expansion factor you need to consider.
 
How about a messenger wire?

I think if you end up with a structure, the building code will require a set of drawings. In many cases that may require a seal from a PE or architect.

The weight and wind load of such a thing may impact how it is hooked to the two buildings it spans.
 
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petersonra said:
How about a messenger wire?

I think if you end up with a structure, the building code will require a set of drawings. In many cases that may require a seal from a PE or architect.

The weight and wind load of such a thing may impact how it is hooked to the two buildings it spans.
Click to expand...

That was going to be my suggestion. Wind load of something spanning that far will make it a pretty hefty object, use a messenger wire and either open outdoor rated fiber or use flexible raceway supported by the messenger.
 
I bet I could span a 15' piece of strut horizontally off each building with an angle brace and some guy wires so you only have 10' gap or so in the middle you have to bridge with conduit....just an idea.

Or you could build some metal posts with a flange you bolt to the concrete and run across the tops of those....?
 
Look on the poles

Look on the poles

There is fiber running on power poles all around here.
Around here they seem to use a steel messenger and tie the cable to it.
I am sure everything they use is off the shelf and in sombodys catalog.
That run of cable would have to be rated for outdoor use (UV proof).
You can strap a flexable conduit (plastic tube) to the messenger wire. I have not seen flex rated for outdoor use but there must me some.
Check out the stuff on poles, if you have to buy the Verizon, Comcast man a cup of coffee.
 
BJ Conner said:
There is fiber running on power poles all around here.
Around here they seem to use a steel messenger and tie the cable to it.
I am sure everything they use is off the shelf and in sombodys catalog.
That run of cable would have to be rated for outdoor use (UV proof).
You can strap a flexable conduit (plastic tube) to the messenger wire. I have not seen flex rated for outdoor use but there must me some.
Check out the stuff on poles, if you have to buy the Verizon, Comcast man a cup of coffee.
Click to expand...

I sure hope liquid tight flexible metallic and non metallic are for outdoor use, I have been using both outdoors for years.
 
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