Historically, SJI specifications have allowed joist design using 36 ksi or 50 ksi yield strength material or material with tensile strength of 18 ksi to 22 ksi depending on the joist series. In 1966, the SJI specifications required the use of 36 or 50 ksi material for joist design. In 2010, the SJI specification required the use of 50 ksi yield strength material for top and bottom chords and 36 ksi or 50 ksi yield strength material for webs. Since the 1980’s, joist manufacturers have predominantly used 50 ksi yield strength material for all joist webs and chords.

50ksi