1. Direct Strength Prediction of Cold-Formed Steel Beam-Columns Y. Shifferaw, B.W. Schafer Report to AISI February 2012

3. Current Progress

4. Prelim. Formulation (dist. 1 of 2) 

5. Prelim. Formulation (dist. 2 of 2)

6. Modeling Nonlinear shell FE models of imperfect CFS member End displacements over desired P, M x, M y Boundary conditions and lengths to isolate local and distortional buckling Preliminary models completed with success

7. P-M major, distortional, C section

8. P-M minor, distortional, C section

9. Local DSM vs minor axis strength bounds for C Potential!

10. Selecting industry relevant beam-columns Trusses

11. Load combinations D+LLD+0.75LL+0.75WD+LL+W Fy (ksi)L- ftWPa-lbMa-ft.lbP- lbMmaxInteractionPM maxInteractionP lbM max- lbinInteraction DEVCO Lower level 600S162-54509 15 psf50981947 3088 lb502lb-ft0.8872576lb536lb-ft0.727 ADTEK-Exterior bearing wall 600S200-54-3rd floor5011.522psf/29p/f70932326.64000479.40.81 600S250-68-2nd floor5010.4222psf/29p/f10711.23251.28300393.60.92 600S250-97-1st floor5010.4222psf/29p/f17399.14801.312600393.60.83 NUCON 1st Exterior End walls 550NF150-43 @16" 501025.17psf3.540kips1.068ft-kips2.383kips0.418ft-kips0.89 1st Exterior walls 550NF150-43 @2" 501025.17psf3.540kips1.068ft-kips1.840kips0.629ft-kips0.92 2nd Exterior walls 550NF150-43@2" 5010.525.01psf3.540kips1.068ft-kips1.280kips0.689ft-kips0.82 1st interior wall at unit AL-A 550NF150- 33@16" 50105psf2.371k0.751ftk2.329k0.083ft-kips0.98 1st interior wall at unit AL-A 350NF150- 43@16" 50105psf2.592k0.588ftk 2.329k0.083ft-kips0.9 Selecting industry relevant beam-columns Framing

12. Selecting efficient sections Most efficient P n /A M n /A

13. Identifying SSMA sections based on limit state

15. Selecting Member length

16. Testing Related recent testing: Basic basis for our forthcoming testing…

17. Current Progress Conclusion: work is modestly behind, but progress being made. Looking forward to providing More results, including testing results, at July meetings.