Schedule 5, 10, and 20 pipe? ASTM A53 grade?

[dlclarkii]

I've used schedule 40, 80, and 120 countless times but I got a request to use schedule 10 or 20. I have the section properties so calculating strength properties isn't an issue assuming it's A53 grade? But can I use it for structural purposes? I need to span a pipe 18' horizontally to support several live loads at points. I could go with HSS round but the cusotmer wants to keep the cost down with just regular pipe. Thank you!

 

[racookpe1978]

My father, a loooong-time structural engineer, has strongly warned me about using "pipe" for ANY structural steel application.

Rather, use the term Hollow Round Structural Section (HSSR) to order and specify "pipe-looking" round steel things.

Conventional "pipe" is not as straight nor as rigorously controlled in wall thickness as fluid-bearing lines that are intended to carry flowing internally-pressurized liquids, even though the "pipe" may have the wall thickness you want. In fluid applications, the pipe's internal pressure will tend to straighten and "rounden" the pipe, to strengthen it against the stresses imposed. But under external structural loads of bending and moments and shear, the more-irregular "pipe" tolerances will exaggerate flaws.

 

[JStephen]

racookpe1978, is that restriction actually reflected in the building codes? Or is that just a personal preference?

In the ME world, I have run across people (mainly online) that are convinced that A36 is the vilest crap that was ever produced. Or for some people, it's foreign steel.

 

[PrescottEngineer]

dlclarkii,

I have seen schedule 10 and 20 pipe used on a few residential projects before. I was asked to verify existing member capacity and them members were ok based on my calculations. The pipes had been in place for a few years which obviously doesn't mean they saw the design loads, but just that they functioned acceptably under some portion of the design loads. I don't see why you can't use it for structural purposes. I think someone would have a difficult time arguing that 4" schedule 10 pipe with an outside diameter of 4.500" and a 0.120" wall thickness is really all that different from an HSS4.500×0.125 which has a design wall thickness of 0.116".I would assume A53 and specify that on your drawings. If you are concerned about the grade you can require that the manufacturer's certified test reports are sent you. We are on the 2006 IBC and require this on every project. However, it is rarely enforced by the building department which is possibly why it was added to required special inspection items for steel construction in the 2009 IBC.

I would have to guess that spanning 18' is going to be pretty difficult with something less than schedule 40 pipe.

Good luck.

 

[amec2004]

We always use ASTM A252 grade 2 or 3 for steel pipe pile.

I don't think it's a problem if 1) you sue the correct Fy 2) make sure it's weldable if you need welding

anchor bolt design per ACI 318-11 crane beam design

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