Design of Steel Catwalk Truss that is 3 sided

[Berniedog]

I am being asked to design a truss for a feed conveyor that is just 3 sided. Meaning the outside handrails are part of a the truss and the walking surface is also but there is no top to the truss/conveyor. The top chord will be unbraced from support to support. For an example see the following link and scroll down 9 rows to one view a picture that has one:

http://www.lemarindustries.com/new/index.php/2012-04-25-04-56-01

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To design one, I suppose you just design the top chord as a compression member with an unsupported length of the span. Any ideas?

 

[bridgebuster]

The AASHTO guide spec for ped bridges provides an example for designing a pony truss. It's also covered in "Guide to Stability Design Criteria for Metal Structures" - Galambos (editor).

 

[Berniedog]

Thanks

 

[bridgebuster]

good luck