BeamColumns-AISCInteractionEquations.pptVIP

Beam-Columns Members Under Combined Forces Interaction Formulas for Combined Forces Basis for Interaction Formulas AISC Interaction Formula – CHAPTER H REQUIRED CAPACITY Pr Pc Mrx Mcx Mry Mcy Axial Capacity Pc Axial Capacity Pc Effective Length Factor Effective Length of Columns Effective Length of Columns Axial Capacity Pc Axial Capacity Pc Moment Capacity Mcx or Mcy Moment Capacity Mcx or Mcy Moment Capacity Mcx or Mcy Demand Axial Demand Pr Demand Second Order Effects Moment Amplification Second Order Effects Moment Amplification Second Order Effects Moment Amplification Design Codes Derivation of Moment Amplification Derivation of Moment Amplification Derivation of Moment Amplification Derivation of Moment Amplification Derivation of Moment Amplification Derivation of Moment Amplification Braced vs. Unbraced Frames Braced vs. Unbraced Frames Braced Frames Braced Frames Braced Frames Braced Frames Braced Frames Braced Frames Braced Frames Unbraced Frames Unbraced Frames Unbraced Frames Unbraced Frames Unbraced Frames Unbraced Frames Eq. C2-1a Eq. C2-1a Mnt = Maximum 1st order moment assuming no sidesway occurs Mlt = Maximum 1st order moment caused by sidesway B1 = Amplification factor for moments in member with no sidesway B2 = Amplification factor for moments in member resulting from sidesway Pr = required axial compressive strength = Pu for LRFD = Pa for ASD Pr has a contribution from the PD effect and is given by a = 1 for LRFD = 1.6 for ASD Cm coefficient accounts for the shape of the moment diagram Cm For Braced NO TRANSVERSE LOADS M1: Absolute smallest End Moment M2: Absolute largest End Moment Cm For Braced NO TRANSVERSE LOADS COSERVATIVELY Cm= 1 Eq. C2-1a Mnt = Maximum 1st order moment assuming no sidesway occurs Mlt = Maximum 1st order moment caused by sidesway B1 = Amplification factor for moments in member with no sidesway B2 = Amplification factor for moments in member resulting from sidesway a = 1