In: Civil Engineering
A lumber floor joist is designed from Douglas Fir-Larch number 1 and better. The joist is simply supported over a span of 12' and is part of a floor system that includes repetitive joist framing at 16" o.c and a plywood subfloor. Assume dry and normal temperature service conditions. The joist carries 25 plf of dead load and 55 plf of live load. Size the joist.