sji unit stresses in 1964

huangyhg

sji unit stresses in 1964
what was the unit steel stress, in psi, used in the sji standard specifications for open web steel joists j-series dating back to the year 1964? i am checking the capacity of an existing roof truss to support additional weight due to replacement of mechanical roof top units.
thank you for your help.

check out our whitepaper library.
per the 1961 sji spec for h-series joists they refer to a36.
fy = 36 ksi.

sji has an excellent website -
you can even buy a book that covers all bar joists back to 1928
i appreciate the replies... while i am waiting on the delivery of my book... can you please tell me
what would the section size be for the top, bottom and web   
the chord and web sizes varied from manufacturer to manufacturer. the sji book just gives specs and load tables.
if you check the existing joist you may be able to find some joist tags wired to the ends of the joist.  they could tell you the manufacturer and sometimes the joist design. i recently called sji with some info. off a joist tag, along with joist member dimensions, and sji could identify the maker and sent me a load table for joist installed in the 1940's.