Flue gas ductwork

[StrP88]

Hi

I am working on designing a cover plate to cover an opening (20ft by 24ft) as result of removing an attached duct from this duct.
I am aware of ASCE publication and have read through
However I have few questions, is there any deflection limitation for the plate? What number shall I check against
Anywhere, publication or Handbook containing a full example
Is the cover plate rigidly attaches to surrounding plate?

Thanks

 

[DSB123]

deflection limit for plate - depends on what theory you are going to apply to the design. Flat plate theory is only valid for deflections less than half the plate thickness. After that you need to use the membrane plate theory. So long as you meet the stress criteria for membrane stress then you should be OK unless the deflection at the bolted outer edge (assuming you are bolting) does not cause the contents to leak.

 

[thaidavid40]

The plate stiffness (i.e.: the rotation at the edges) should at least match that of the previously-connected intersecting duct. Beware of plates so thin that they vibrate or deflect wildly with the passage of air inside - especially if the air flow has pulses, or is intermittent.

Thaidavid