I have two sets of parameters in STAAD, Parameter 1 for deflection check, and Parameter 2 for Stress Check. I would like to suppress the stress check on parameter 1 because I want to have two sets of steel design result (Deflection and Stress). However, if the stress ratio is greater than the deflection ratio, steel design output will show stress ratios instead of deflection (this is my understanding, correct me if I'm wrong). I understand that setting DFF to 0 will suppress deflection check and Main 1 for slenderness check suppression, but is there a way or a parameter used to suppress stress check so that STAAD will only show purely deflection check? I think I've done this in BS5950 by using TRACK command, what is the counterpart of this command in AISC ASD? Thank you and more power.
Hello,
AISC does not have any such TRACK 4 command as in BS or EC 3 codes .
I would suggest you to crate 2 different load envelope: one for deflection check using the serviceability load cases and the second load envelope for stress check using the ultimate load cases . Now use 2 separate set of PARAMETER , let’s say PARAMETER 1 will use the ultimate load cases and hence do a stress check and PARAMETER 2 will use the serviceability load cases and hence do a deflection check.
If you want pure deflection output in PARAMETER 1 then use that parameter for serviceability load cases only and use the PARAMETER 2 for stress check using ultimate load cases only . This can be done either by the load envelope or the LOAD LIST command.
Lets say you have load cases 1 to 10 as serviceability load cases and load cases 50 to 100 as ultimate load cases , so you need to define :
LOAD LIST 1 to 10
PARAMETER 1 // This is for serviceability check or deflection check
**********
CHECK CODE All
LOAD LIST 50 to 100
PARAMETER 2 // This is for stress check using ultimate load cases
************
CHECK CODE ALL
Hello Shany, thanks for answering.
Let's say I only have Parameter 1 (deflection check using load list 1 to 10). Let's disregard Parameter 2 (Stress check). I defined DFF, DJ1 and DJ2 for Parameter 1 , but not defining FYLD, KY, KZ, UNT, UNB and so on in STAAD means setting it to default values and doesn't mean they are non-existent, which means that even the parameter is set for deflection check, STAAD will automatically calculate stress capacities based on the default values (correct me if I'm wrong). Therefore, in case that the stress ratio based on default values is greater than the deflection ratio, steel design output will still be in stress ratios. I can't find any alternative command, I'm really confused right now :(
Thank you very much
To the best of my knowledge, this can be achieved by the LOAD ENVELOPE command in Staad using the AISC UNIFIED code.
Lets say you define :
PER ANA
DEFINE ENVELOPE
1 TO 10 ENVELOPE 1 TYPE service
50 TO 100 ENVELOPE 2 TYPE STRESS
END DEFINE ENVELOPE
LOAD LIST ENV 2
PARAMETER 1
CODE AISC UNIFIED 2010
METHOD LRFD
TRACK 2 ALL
DFF 100 ALL
This means this will do only a deflection check based on load cases 1 to 10, stress check will not be done here.