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Machel Morrison Doug Schweizer Tasnim Hassan (PI)

Experiments and Simulations of an Innovative Performance Enhancement Technique for Steel Building Beam-Column Connections. Machel Morrison Doug Schweizer Tasnim Hassan (PI). Post Northridge Research. Bolted Extended Endplate. Bolted Flange Plate .

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Machel Morrison Doug Schweizer Tasnim Hassan (PI)

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  1. Experiments and Simulations of an Innovative Performance Enhancement Technique for Steel Building Beam-Column Connections Machel Morrison Doug Schweizer Tasnim Hassan (PI)

  2. Post Northridge Research Bolted Extended Endplate Bolted Flange Plate AISC 341 Performance Criteria θd=0.04 Radians Kaiser Bolted Bracket WUF-W Reduced Beam Section Figures from Hamburger et. al 2009

  3. Heat Treated Beam Section (HBS) Mf ∝ MRBS Mf ∝ MHBS

  4. Heat Treated Beam Section (HBS) Figure from :http://textbooks.elsevier.com

  5. Induction Heating - Eddy currents “induced” by alternating magnetic field • Advantages: • Lower energy Input than traditional heating sources • Easy to localize heat input Induction heating provided by Ameritherm Inc.

  6. Induction Heating Challenges: -Difficult to control temperature uniformity -Prescribed slow cooling rate was not achieved

  7. Experimental Program -4 Full Scale WUF-W -3 HBS and 1 Unconditioned -Sub assemblage similar to Engelhardt et al 1998- DB5

  8. Experiment Results 0

  9. Experiment Results WUF-W HBS HBS

  10. Experiment Results WUF-W HBS

  11. Challenges -Significant yielding spread beyond HBS region and higher moments than expected

  12. FE Simulations ANSYS 12.1 Mechanical ADPL -Quadratic Shell Elements -Finite Strain, Large Displacement Formulation -Initial Geometric Imperfections (Flange thickness variation, out of straightness)

  13. FE Simulation- Constitutive Model -Non Linear Kinematic Hardening Model (Chaboche 1986) Yield Surface Flow Rule Chaboche Kinematic Hardening Rule

  14. Validation of FE Simulation

  15. Validation of FE Simulation WUF-W

  16. FE Simulation Results

  17. Expt Results- Flange Buckling HBS WUF-W

  18. Validation of FE Simulation

  19. FE Results- Flange Buckling

  20. FE Results- Flange Buckling No Shear tab/Supplement weld Shear tab w/Supplemental Weld

  21. FE Results- Flange Buckling

  22. FE Results –Flange Buckling WUF-W Ricles et. al 2002

  23. Summary -Heat treatment of beam flanges reduces strength of steel and initiates yielding in the heat treated regions -Uniform heat pattern difficult to achieve with Induction heating, σ-ε response varied from furnace heat treatment -Heavy shear w/supplemental fillet weld to beam web influences local flange buckling -Future experiments are being planned with new heat treatment technique

  24. Acknowledgments -National Science Foundation (NSF) -Network for Earthquake Engineering Simulation (NEES) -MAST LAB @ U of Minnesota -Lejune Steel Company -Ameritherm Inc.

  25. New Heat treatment Technique

  26. COMPARISON WUF-W, HBS & RBS RBS No Shear tab/Supplemental weld WUF-W No Shear tab/Supplemental weld HBS No Shear tab/Supplemental weld

  27. COMPARISON WUF-W, HBS & RBS WUF-W From Hassan and Syed 2009

  28. Moment Response

  29. Moment Response

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