stair tread pan design

[MikeE55]

Anyone know how to design a concrete-filled cold-formed metal stair tread? I have seen specs that call for 12 gage. Is this just based on what has worked before? Anybody know of any span tables?

 

[whyun]

Try Google: NAAMM Metal Stairs as a starting point.

Also follow this link to the Metal Stairs Manual from NAAMM.

http://www.naamm.org/literature.php