cold formed steel joist data

huangyhg

cold formed steel joist data
i'm doing an evaluation of an prefabricated  metal building. i'm looking for data on the buildings steel joists. the steel joist's bottom and top chord are not double angles. they are similar to the shape drawn here  \__|¯¯|__/  .  the web elements are bent pipe sections 3/4" in diameter. is there a design manual or load table for this type of steel joists? thanks!
is it possible for you to get data from the original manufacturer?
the building is 35 years old. the manufacturer has been out of the industry for years.
the shape looks similiar to a macomber joist from the 60's and 70's. but off just a bit from the bottom chord shape shown in their catalog.
a copy of the last macomber catalog can be downloaded from slideruleera's web site. but again, the shape seems to be slightly off.
did you get a joist tag? that should list the manufacturer.
if it is a standard sji joist, you should be able to use a standard sji catalog for load tables. if it is a non-standard sji joist, and you know the manufacturer then maybe one of us might have a catalog to help. please note that the type of chords or web do not necessarily make it a non-standard sji joist, the joist designation does.
how do you know the webs are pipes? are you sure they are not rods?
macomber made several different types of chords and that might be one of them. macomber went out of business in the late 60's, early 70's.
i now they are pipes because some of them have a small hole throught and you can see it is a pipe. the thickness of the wall is .125".
i recognize the shape... they are cold-formed metal joists produced by butler manufascturing, for their "landmark" product line, back in the 70's (i worked for them). the joists were made at their laurinburg, nc fabrication plant. i don't know when they stopped producing them, but i'm sure they don't make them anymore.
the chords were the cold-rolled "hat" sections that you show in your sketch. the web   
spats is correct! butler did produce these type of joists.  i think that they called them "truss purlins".