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Structural
- Sep 2, 2022
- 7
I'm trying to get a better understanding of strength and stiffness requirements for steel per AISC 360-22.
I have a few questions about Example A-6.2 from SCM Design Examples V16.0 (attached). It shows a 36 ft long pinned-pinned WT-shape column with W-shape point braces at quarter points (7'-6" apart). The W-shape braces are 12 ft long, simply supported, and rotated such that the flanges of the braces and the flange of the WT columns are attached at the midspan of the W-shape braces.
1) Strength and stiffness requirements for lateral bracing of columns is given in Appendix 6. I know that in most cases flexural buckling about the minor axis of bending will control over torsional buckling about the longitudinal axis, but are there any strength or stiffness requirements for torsional bracing of columns?
2) The example assumes that the W-shape beams bracing the column are laterally braced and compact such that they can reach their plastic moment capacity. It uses this assumption when calculating the minimum plastic section modulus needed for the brace. Does the column laterally brace the beam against lateral-torsional buckling while the beam braces the column against flexural buckling such that the unbraced length of the W-shape brace is 6'-0"? Or is the unbraced length of the W-shape brace the full 12'-0"?
3) The example states that the WT is assumed braced against flexural buckling about its y-axis by the axial strength and stiffness of the W-shape brace. Similarly to my last question, if one were to check the axial strength of the W-shape brace, does the WT column brace the W-shape against flexural buckling?
I have a few questions about Example A-6.2 from SCM Design Examples V16.0 (attached). It shows a 36 ft long pinned-pinned WT-shape column with W-shape point braces at quarter points (7'-6" apart). The W-shape braces are 12 ft long, simply supported, and rotated such that the flanges of the braces and the flange of the WT columns are attached at the midspan of the W-shape braces.
1) Strength and stiffness requirements for lateral bracing of columns is given in Appendix 6. I know that in most cases flexural buckling about the minor axis of bending will control over torsional buckling about the longitudinal axis, but are there any strength or stiffness requirements for torsional bracing of columns?
2) The example assumes that the W-shape beams bracing the column are laterally braced and compact such that they can reach their plastic moment capacity. It uses this assumption when calculating the minimum plastic section modulus needed for the brace. Does the column laterally brace the beam against lateral-torsional buckling while the beam braces the column against flexural buckling such that the unbraced length of the W-shape brace is 6'-0"? Or is the unbraced length of the W-shape brace the full 12'-0"?
3) The example states that the WT is assumed braced against flexural buckling about its y-axis by the axial strength and stiffness of the W-shape brace. Similarly to my last question, if one were to check the axial strength of the W-shape brace, does the WT column brace the W-shape against flexural buckling?
