Steel Moment Frames with Large Dia Pipe..any details?

[PatrickCrosby]

I am looking to create a steel ductile moment frame using large diameter steel pipe (30"+). Does any one know of a good resource for prior testing and or details?

Thanks

 

[shemp]

If you find something, please post it. AISC's seismic provisions and FEMA 350 currently don't allow any other shapes besides wide-flange columns for special moment frames, unless testing is performed.

Shemp

 

[GraemeL]

Hi there,

Offshore platforms have jacket structures made from tubulars. They are most often concentrically braced structures but the smaller ones (usually unmanned platforms) sometimes are moment resisting frames. As the platforms have to resist horizontal environmental loads and maybe earthquakes, they have had some investigative work into how their joints work.

A good place to start is API's Recommended Practices for Planning, Designing and Constructing Fixed Offshore Platforms. There is a LRFD version (API RP-2A-LRFD) and a Working Stress version (API RP-2A-WSD).

The LRFD version maybe better for checks on ductile behaviour of the joints but I have never used it. The joints will be the difficult bit and soon as you put any stiffening in, the RP's are only a guide.

You are then into looking at papers on the subject, for example:

"A theoretical model for predicting the strength of ring-stiffened tubular T-joints in offshore structures" Lee and Llewelyn-Parry, Proc. Institution of Civil Engineers, Structures and Buildings, February 1999.