Product(s):	SACS
Version(s):	ALL
Area:	Post Solution

Community Question?

Hello Bentley, I am working on an analysis in which I need to include the card CODE AA to consider the P delta factors,  I usually add the card in Datagen, save the model, and close it, but at the moment to open and save using precede this card is removed from my model, could you explain the reason for this?

Answer

If at the moment save your model in precede you come across a similar issue the reason for this is the incompatibility in the card CODE AA thought to work only with AA-WDS AISC 13th/API-RP2A 21st with the code in the model, if you are using AISC version 14th of 15th, is probable that you have this issue problem

AISC 13th Edition code of practice considers two kinds of second-order effects in accordance with section C2.1b as follows.

• Second order P-δ effect caused by loads acting on the deflected shape of a member between joints or nodes will be automatically considered in POST program. Factor B1 from equation C2-2 is used to
  account for P-δ effects.

• Second order P-Δ effect caused by loads acting on the displaced location of joints or nodes in a structure will not automatically be considered in POST program. It is recommended that the SACS P-Δ analysis option is used when doing code check analysis using AISC 13th Edition. The following message will be issued by POST when using the “AA” or “AL” code check options: “(6) WHEN USING THE AISC 13th EDITION (2005 SPECIFICATIONS) CODE CHECK, THE USER SHOULD HAVE THE PDELTA EFFECT INCLUDED IN THE ANALYSIS”