I ▁S 1 0 0 - 0 7 ). ▁ ▁D SM ▁may ▁be ▁used ▁in ▁lieu ▁of ▁the ▁Main ▁Spec ification ▁for ▁determ ining ▁nom inal ▁member ▁capac ities . ▁Specific ▁advantages ▁include ▁the ▁absence ▁of ▁effective ▁width ▁and ▁iterations , ▁while ▁only ▁using ▁known ▁gross - section al ▁properties . ▁An ▁increase ▁in ▁prediction ▁confidence ▁st ems ▁from ▁forced ▁compatibility ▁between ▁section ▁fl anges ▁and ▁web ▁throughout ▁el astic ▁bu ck ling ▁analysis . ▁This ▁increase ▁in ▁prediction ▁accuracy ▁for ▁any ▁section ▁geometry ▁provides ▁a ▁solid ▁basis ▁for ▁rational ▁analysis ▁extension ▁and ▁encourag es ▁cross - section al ▁optimization . ▁ ▁Either ▁D SM ▁or ▁the ▁main ▁specification ▁can ▁be ▁used ▁with ▁confidence ▁as ▁the ▁ Φ ▁or ▁ Ω ▁factors ▁have ▁been ▁designed ▁to ▁ins ure ▁that ▁both ▁methods ▁are ▁accurate . ▁Currently , ▁D SM ▁only ▁provides ▁solutions ▁for ▁be ams ▁and ▁columns ▁and ▁has ▁to ▁be ▁used ▁in ▁conj unction ▁with ▁the ▁main ▁specification ▁for ▁a ▁complete ▁design . ▁ ▁R ational ▁analysis ▁is ▁permitted ▁when ▁using ▁optimized ▁cold ▁form ▁shapes ▁that ▁are ▁outside ▁of ▁the ▁scope ▁of ▁the ▁main ▁specification ▁and ▁are ▁not ▁pre - qual ified ▁for ▁D SM ▁use . ▁These ▁non - pre - qual ified ▁sections ▁use ▁the ▁factors ▁of ▁safety ▁of ▁ ϕ ▁and ▁ Ω ▁associated ▁with ▁rational ▁analysis ▁( see ▁A IS I ▁ 2 0 0 1 ▁Section ▁A 1 . 1 ▁( b )). ▁The ▁result ▁of ▁the ▁rational ▁analysis ▁times ▁the ▁appropriate ▁factor ▁of ▁safety ▁will ▁be