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1
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warrywall
Structural
- Aug 7, 2009
- 8
I just re-started using STAAD last week. I did not use it for many many years. Research Engineers used to be the owner, now it is a Bentley product as you'all know.
I did not feel comfortable on just using STAAD without testing it again.
In doing that, I came across some findings that I would like to share with you guys:
I have reported these to Bentley and they are looking at it
1.- When code checking with AISC 360-05, STAAD checks "W" shapes (i.e.: rolled shapes) using Section E4, however it applies to built-ups, not to rolled shapes. It was only till AISC 360-10 when Section E4 can be applied to "W" shapes.
2.- The ratio h/tw should be calculated as = (d-2*k_des)/tw and not = (d-2*tf)/tw as this results that some shapes that for AISC are not slender for STAAD they are and hence designed incorrectly.
3.- When code cheking Angles with AISC 360-05, STAAD adds the eccentricity effects incorrectly.
4.- Insertion of intermediate nodes are required in order to address the P-little-delta effects when using either the P-Delta with small Delta or the Direct Analysis Method commands.
5.- STAAD is not checking the condition specified for the applicability of Equations H1-1 for singly symmetric sections. Due to this some sections that should be checked with with Equation H2-1 instead are checked incorrectly with Equations H1-1. This is the case of Tee shapes, double angles and many other shapes that do not satisfy the condition 0.1 ≤ (Iyc/Iy ) ≤ 0.9. Check question #10 in the following AISC quizz:
6.- Equation H2-1 is not code checked properly.
7.- Obtained different Utilization Ratios between AISC 360-05 and AISC 360-10 for members controlled by equation H1-1a. This should not be like that because there were not changes in these equations or in the parameters used to justify the discrepancy.
8.- Obtained different Utilization Ratios between AISC 360-05 and AISC 360-10 for members controlled by equation H1-1b. This should not be like that because there were not changes in these equations or in the parameters used to justify the discrepancy.
Should you guys would like further information, do not hesitate to contact me.
I did not feel comfortable on just using STAAD without testing it again.
In doing that, I came across some findings that I would like to share with you guys:
I have reported these to Bentley and they are looking at it
1.- When code checking with AISC 360-05, STAAD checks "W" shapes (i.e.: rolled shapes) using Section E4, however it applies to built-ups, not to rolled shapes. It was only till AISC 360-10 when Section E4 can be applied to "W" shapes.
2.- The ratio h/tw should be calculated as = (d-2*k_des)/tw and not = (d-2*tf)/tw as this results that some shapes that for AISC are not slender for STAAD they are and hence designed incorrectly.
3.- When code cheking Angles with AISC 360-05, STAAD adds the eccentricity effects incorrectly.
4.- Insertion of intermediate nodes are required in order to address the P-little-delta effects when using either the P-Delta with small Delta or the Direct Analysis Method commands.
5.- STAAD is not checking the condition specified for the applicability of Equations H1-1 for singly symmetric sections. Due to this some sections that should be checked with with Equation H2-1 instead are checked incorrectly with Equations H1-1. This is the case of Tee shapes, double angles and many other shapes that do not satisfy the condition 0.1 ≤ (Iyc/Iy ) ≤ 0.9. Check question #10 in the following AISC quizz:
6.- Equation H2-1 is not code checked properly.
7.- Obtained different Utilization Ratios between AISC 360-05 and AISC 360-10 for members controlled by equation H1-1a. This should not be like that because there were not changes in these equations or in the parameters used to justify the discrepancy.
8.- Obtained different Utilization Ratios between AISC 360-05 and AISC 360-10 for members controlled by equation H1-1b. This should not be like that because there were not changes in these equations or in the parameters used to justify the discrepancy.
Should you guys would like further information, do not hesitate to contact me.
