I have a copy of the 1973 UBC. This was before my time, so I am not totally
familiar with it. It doesn't appear to have been changed from the 1970 UBC
as evidenced by no revision bar in the margin. It appears the Combination
Symbol A is for hardwoods, not softwoods such as Douglas Fir, and it is used
in conjunction with Tables 25-D Part A and 25-D Part B to arrive at the
The combination symbols for D.F. are 16F, 18F, 20F, 22F, and 24F, which have
no rating for weak axis bending, and 1, 2, 3, 4, and 5 for combinations
rated for both strong and weak axis bending.
Reply to me privately, and I could fax you a copy of these tables.
Conrad Guymon, P.E.
I am checking the roof structure for a building built in 1971. Does anyone
have the UBC for this time period?
More specifically, I am looking for the allowable design stresses for a
Glulam beam that is D.F. Combination 'A.'
Any information is greatly appreciated...
Gina T. Gobo, EIT
Carter & Burgess, Inc
Facilities - Structural Engineering