▁ 1 9 8 6 ▁to ▁reflect ▁the ▁technical ▁develop ments ▁and ▁the ▁results ▁of ▁continued ▁research ▁at ▁Corn ell ▁and ▁other ▁univers ities ▁( Y u ▁et ▁al ., ▁ 1 9 9 6 ). ▁Both ▁AS D ▁and ▁L R FD ▁Spec ifications ▁were ▁combined ▁into ▁a ▁single ▁specification ▁in ▁ 1 9 9 6 ▁( A IS I , ▁ 1 9 9 6 ). ▁It ▁included ▁the ▁AS D ▁and ▁L R FD ▁methods ▁for ▁the ▁United ▁States ▁and ▁Mexico ▁together ▁with ▁the ▁Lim it ▁States ▁Design ▁( L SD ) ▁method ▁for ▁Canada . ▁This ▁North ▁American ▁Spec ification ▁has ▁been ▁acc red ited ▁by ▁the ▁American ▁National ▁Standard ▁Institute ▁( AN SI ) ▁as ▁an ▁A NS I ▁Standard ▁to ▁su pers ede ▁the ▁ 1 9 9 6 ▁A IS I ▁Spec ification ▁and ▁the ▁ 1 9 9 4 ▁C SA ▁Standard . ▁Following ▁the ▁successful ▁use ▁of ▁the ▁ 2 0 0 1 ▁edition ▁of ▁the ▁North ▁American ▁Spec ification ▁for ▁six ▁years , ▁it ▁was ▁re vised ▁and ▁expanded ▁in ▁ 2 0 0 7 . ▁ ▁This ▁updated ▁specification ▁includes ▁new ▁and ▁re vised ▁design ▁prov isions ▁with ▁the ▁add itions ▁of ▁the ▁Direct ▁Str ength ▁Method ▁in ▁Append ix ▁ 1 ▁and ▁the ▁Second - Order ▁Analysis ▁of ▁struct ural ▁systems ▁in ▁Append ix ▁ 2 . ▁ ▁In ▁addition ▁to ▁the ▁A IS I ▁specific ations , ▁the ▁American ▁Iron ▁and ▁Ste el ▁Institute ▁has ▁also ▁published ▁comment aries ▁on