Good references for design of circular ducts with large D/t?

[PAeng22]

I am designing large circular ductwork and am always looking for more good references, especially ones that address stiffening rings. There doesn't seem to be much new out there lately. Most references discuss the need for stiffeneing rings only when there is negative internal pressure. What about adding stiffening rings to increase buckling capacity and therefore increase span when bending moment is significant (with or without internal pressure)?

My main references have been Troitsky, SMACMA, AISC, AISI Plate Engineering Data Vol II, TM 5-809-6, ASME ST-1-2011, ASCE "Structural Design of Air and Gas Ducts for Power Stations and Industrial Boiler Applications" (this book tells you what to do but not really how to do it).

Does anyone know where I can get a copy of the two references below? These seem like they may have some useful information.
1. "Analysis of Circular Conveyor Galleries", H.M. Haydl (1980)
2. "Design Aspects of Large Diameter Tubular Conveyor Galleries", H.M. Haydl (1986)

 

[rb1957]

i get using rings to reduce your length and increase your buckling allowable, but if bending is the issue, why not add axial stiffeners, which would also increase the buckling allowable of the skin ?

another day in paradise, or is paradise one day closer ?

 

[SAIL3]

I have picked up info/methods from a variety of sources most of which the OP mentioned ie. stack design, asme code etc. If I recall correctly, I have used a max stiff sp of 3D. Where it gets complicated is when one has a loading condition that is unsymmetrical....dust load, snow load etc...in these cases I have always been conservative in the stiff sp....fab and shipping may also influence the stiff size and spacing...have not heard of the two references in question, but they sound interesting...

 

[SAIL3]

correction, that should be a max sp of stiff of 1.5D.....

 

[ldeem]

Try Roark, Tubular Steel Structures by Troitsky and of course Blodgett

I did a duct last year using FEA to get the plate stresses and ring spacing to determine allowable shell buckling stress.

 

[ldeem]

Don't forget to consider the lifting/install case