orthotropic plate design

[senthil83]

i want to design a plate grider with web stiffened to resist lateral pressure load on web of around 300 mm WC.
since this plate grider is used to support the duct with internal pressure of 300mmWC .

Please let me know how to design the plate grider web , i have searched in web and found orthopice plate design may be the best soluition. please let me know how to do this? is there any codes available for this type of design.

 

[BAretired]

From a structural point of view, a pressure of 300 mm WC is a trivial pressure (61.4 psf) and could almost be ignored unless the depth of girder is large. If you want to take it into account, the bending moment in the girder web is wh²/8 where w is the uniform pressure and h is the depth of girder.

BA

 

[msquared48]

Back in the 60's or 70's, AISC produced a book on Orthotropic Bridge design.
I have a copy stashed away somewhere, but, quite frankly as BA suggests, that might be somewhat of an overkill here.

Mike McCann
MMC Engineering

http://mmcengineering.tripod.com

 

[rb1957]

i'd design web stiffeners that can react the small pressure load in bending and transfer the load to the caps, each stiffener would carry a 1/2 pitch of pressure on both sides.

then you've added a presmably small lateral load into the caps, another thing to consider.

 

[dik]

I think that Lincoln also had a text on orthotropic plate design...

Dik

 

[dhengr]

I’m not even sure that orthotropic is the right term here. This is just a stiffened plate under some pressure normal to the plane of the plate. Or a plate girder, IF that’s what it is, with some pressure normal to its web. Aren’t these large ducts made up of four plates, two sides and t&b, maybe stiffened, spanning btwn. supports under their own structural capacity as a beam?

 

[rb1957]

i think he's using the beam web as one side of the duct.

there could well be a point for saying that the duct top and bttm sides will react the pressure load onto the web (and not the beam cap in lateral bending).

 

[BAretired]

Maybe a sketch would be in order.

BA

 

[senthil83]

THANKS FOR YOUR REPLY, I AM USING BEAM WEB AS ONE SIDE OF DUCT

IS THERE ANY BOOKS WRITTEN ON THIS TOPICS?
I WILL UPLOAD SKETCH SHORTLY

 

[BAretired]

Provide a duct with four walls, top, bottom and both sides, each designed to resist the applied pressure. One wall may be loosely attached to the web of the girder if you wish, but the web does not need to be designed for pressure.

I very much doubt that anyone has written a book on the subject.

BA