Sprialwelded Pipe Versus Round HSS

[RyUIUC]

I am looking to specify a concrete filled pipe pile and will likely need something around an 18" diameter with 0.5" thick walls. This seems to be beyond the standard pipe size (astm A53). Looking around online I found some fabricators who offer spiralwelded pipe in larger diameters with a comparable steel strength (astm A252, fy=35ksi). Are these sections more typically specified for piles rather than a round HSS section (astm A500)? Are there any special design or installation issues with either?

 

[ishvaaag]

I think from the 18" diameter you have to maybe 80" diameter if you use relatively small thickness it will be because mainly used as sheat for a concrete (composite or not) pile inside, and normally pre-drilled or in bentonite muds. Otherwise half-inch may be too little considering corrossion etc for what are to be anyway quite competent piles, and prone to damage at the big diameters. Respect the steel, usually the industry proposes solutions according to the use, derived from experience. A screwable micropile by segments pipe needs a somewhat more mechanizable steel than one that as per fabrication needs to be spirally welded. So make a check with the providers of solutions in the specific field of application.

 

[JStephen]

A53 goes up through 26" pipe, actually. The pipe tables in the green ASD book only go up through 12", but A53 pipe should be readily available up through 24" size.

 

[fegenbush]

I agree with JStephen. 18" OD x 1/2" wall thickness is NPS 18 Sch XS (some call this XH, they are the same thing).