3doorsdwn
Structural
- May 9, 2007
- 162
First off, I’m in the process of going from ASD 9th to ASD 13th, so my knowledge of the 13th edition has gaps (ergo my question).
1. What (by the 13th edition) constitutes a Braced Frame (in terms of stiffness)? Until now, I have used various theorems/rules picked up [over the years] from the likes of Yura and my Salmon and Johnson text book on steel structures. (From the latter the equation k=SigPn/h comes. Where SigPn =all loads to be carried in columns resisting sway; h= story height; and k=required story stiffness. Yura had a similar equation.) Appendix 6 has a similar approach, but it is more for individual members.
2. On p.16.1-193 (Sect. 6.3) the required bracing stiffness is given for lateral [beam] bracing. (I am considering my system as nodal bracing.) The thing about this is: in an evaluation of the stiffness of these points, the weak-axis strength of the beam itself is contributing significantly [the beams are pretty heavy: in the W36 range]. I kind of doubt this is what was intended; it’s sort of like saying it is bracing itself. Thoughts?
Thanks in advance!
1. What (by the 13th edition) constitutes a Braced Frame (in terms of stiffness)? Until now, I have used various theorems/rules picked up [over the years] from the likes of Yura and my Salmon and Johnson text book on steel structures. (From the latter the equation k=SigPn/h comes. Where SigPn =all loads to be carried in columns resisting sway; h= story height; and k=required story stiffness. Yura had a similar equation.) Appendix 6 has a similar approach, but it is more for individual members.
2. On p.16.1-193 (Sect. 6.3) the required bracing stiffness is given for lateral [beam] bracing. (I am considering my system as nodal bracing.) The thing about this is: in an evaluation of the stiffness of these points, the weak-axis strength of the beam itself is contributing significantly [the beams are pretty heavy: in the W36 range]. I kind of doubt this is what was intended; it’s sort of like saying it is bracing itself. Thoughts?
Thanks in advance!