Direct Analysis with STAAD Pro

[@TheTrongvu]

Hi Lee, thank you so much for your explain. i have one more question. why do you assign FLEX, FYLD, AXIAL parameter just for one column? How about the other column? or one column is enough for any building? (if we have fix support at end of columns, we will assign the parameters in direct analysis definition for two column,right?)

[@yujinlee1012]

you are right. There is no P-delta effect in pined columns which will be designed using K=1.0 Thanks.

[@TheTrongvu]

Hi Lee, i have a question. If we design with effective length method in Staad Pro, we need P-Delta analysis or just perform analysis. Thank you

[@yujinlee1012]

As you know there are three method for stability analysis.Frist is Amplified first order analysis, second is Effective length, last is direct method.And you have to consider effects as 1.Second order effect (P-delta effect), 2.Flexural, Shear and Axial deformation (STAAD considering it automatically), 3. Geometry imperfection(National load factor), 4.Member stiffness reduction due to residual stress. (Design code already including this effect in the formulas). Also all method have to carry out P-delta analysis to decide whether national load will be apply to design load case or not.

[@TheTrongvu]

Dear Lee, Thank you. I have some unclear matters. As i see, you design and check members with only Perform Direct Analysis command, Has P-Large delta effect caused by wind load been included in your analysis if we use only Perform Direct Analysis command? As i know, effect of wind load + vertical load will make second moment at column base. Do we need consider this in analysis? Please explane to me. Thanks a lot.

[@yujinlee1012]

Hi Trong,Direct analysis is including P-delta effect and capability to reduce stiffness. but Perform P-delta analysis don't have function for reducing stiffness.Thanks.

[@TheTrongvu]

Thanks Lee. If we design with effective length method, we shall use P-Delta analysis comment, right?

[@yujinlee1012]

Please let me know your email, and then I will send a document for direct analysis.

[@TheTrongvu]

Hi Lee, Could you please explain to me the function of CHANGE Command?

[@yujinlee1012]

+Trọng Vũ , CHANGE command allow you can be multiple analysis which mean that STAAD can't analysis linear and nonlinear in a model. so you need CHANGE commend.

[@mohammedalsharif5395]

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