Notion load factor for 0.002 or 0.003

Question

hi 
 good day everyone. 
 I have a question about NOTIONAL LOAD FACTOR . 
 Regarding to AISC 360-16 PAGE 16.1-27 as shown below. 
 (c) In structures to which Section C2.2b is applicable, in lieu of using &tau;b < 1.0 where &alpha;Pr /Pns > 0.5, it is permissible to use &tau;b = 1.0 for all noncomposite members if a notional load of 0.001&alpha;Yi [where Yi is as defined in Section C2.2b(a)] is applied at all levels, in the direction specified in Section C2.2b(b), in all load combinations. These notional loads shall be added to those, if any, used to account for the effects of initial imperfections in the position of points of intersection of members and shall not be subject to the provisions of Section C2.2b(d). 
 1. 
 I try to realize the meaning of that. and if tau-b =1 and notion load will be 0.003 , 
 is that right ? 
 2. 
 and I try to write the syntax in staad as show below. 
 DEFINE DIRECT ANALYSIS FLEX 1 ALL AXIAL ALL FYLD 235000 NOTIONAL LOAD FACTOR 0.003 
 besides these syntax , is that any syntax I need to take care? 
 thank you.

Sye · Answer

1. Correct. 
2. What you specified is correct but in addition, you need to add the notional loads too. More details in the wiki below 
 communities.bentley.com/.../20964.does-specifying-the-notional-load-factor-as-0-002-automatically-define-notional-loads

Sye · Answer

Regarding 1, in Direct Analysis the Taub values are determined iteratively based on the axial force in the member. When you set the notional load factor to 0.003 these iterations are not carried out and Taub is considered as 1 which is what the code recommends. 
 Regarding 2, Added the notional load in X direction for your load case 208. Modified file attached Notional_load_0003_syntax_modified.STD 
 Regarding 3, the direct analysis implementation in STAAD automatically handles that. There is nothing additional that you have to do.

Sye · Answer

1.	I chose load 208 randomly just to explain how the notional load generation works. You need to choose appropriate load cases. 
2.	Correct 
3.	Your pdf shows reactions for load cases 141, 143, 101 etc. I had just included the notional load for case 208 and so these reactions will not be affected by what I did. You need to add notional load to cases as appropriate and then check the results.