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This team exercise involves exploring the influence of changing various design parameters such as lip length, flange width, supports, and stiffeners on the elastic buckling (Mcr) and DSM strength of nominal dimension 8x2x0.5 joists. Each group focuses on a specific parameter and shares their findings in a report.
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Joist Explore and Report nominal dimensions 8x2x0.5 t=0.054 straight corner model
Team Exercises Group 1:Team Lip Examine the influence of changing the lip length or lip geometry on the elastic buckling (Mcr), and (if time) the DSM strength – share then report Group 2: Team Flange Examine the influence of changing the flange width or geometry on the elastic buckling (Mcr), and (if time) the DSM strength – share then report Group 3: Team Supports Examine the influence of adding springs or supports at different appropriate locations in the section on the elastic buckling (Mcr) and (if time) the DSM strength – share then report Group 4: Team Stiffener Examine the influence of adding folded stiffeners at different appropriate locations in the section on the elastic buckling (Mcr) and (if time) the DSM strength – share then report
Group 1: Team Lip • Varied lip length 0.3-2 in., tried return, and 45 • Lip length not local buckling, unless really long • Inc. lip length = inc. dist. Buckling • Lip not controlling allowables on this particular section (800S200-54), even HDS style lip not a big improvement • Did not try thickening the lip… • Cost analysis….
Group 2: Team Flange • Tried bigger flange ( 3 in.).. • 12% increase in capacity • Tried single V in the middle of the 2 in. flange • 17.9% increase in capacity! • Tried other cases in the flange.. Single V was the winner in these trials
Group 3: Team Supports • Put springs on top and bottom flanges, distortional goes up 1.21 • Two spring on top flange up to 1.31 (DB) • Springs on web.. Local went way up! (DB?) • Looked at other locations
Group 4: Team Stiffener • Ribs and V’s in the flange, also looked at stiffening lip, also looked at planking (ribs) in the web • Double planking in the web, with returns, 18% increase in the moment capacity • Flange and lip help DB, but needed something in the web to get a big boost…