Dear all,
I am investigating Design of planar steel frames by using various meta heuristics.
I considered research paper "Design of planar steel frames using Teaching–Learning Based Optimization" as a base paper. As per AISC-LRFD Manual.
By doing FEA analysis I am getting Local internal force in x direction, Local internal force in y direction, Local moment and nodal displacements at each node,
AISC-LRFD Manual failure criteria is required strength constraint.
Kindly go through attached file (Doc2) for more detail.
Thanks
You are looking at the standard interaction equation there. In order to get Pu or Mu, you will need to determine which limit state you intend to investigate and to which code you are bound. Then it is a simple factoring of loads which you could do during post-processing, or pre-analysis by application of a load scale.
Dear madam,
Thanks a lot for your reply.
I am using FEA analysis to get its results in form of Local internal force in x direction, Local internal force in y direction, Local moment and nodal displacements at each node.
But, As per AISC-LRFD Manual. I need
𝑃𝑢 = ?
𝑝𝑛= ?
𝑀𝑢𝑥= Sx * Fy (This value we got)
𝑀𝑛𝑥= ?
Please guide me
Thanks
Typically the "u" subscript designates loading response, and the "n" subscript designates capacity. So for Pu and Mu, factor up your applied loads, and thus your internal force results would already be the factored loading condition (axial response = Pu, strong axis moment = Mux, minor axis moment = Muy). Load factors can be found in chapter 2 of AISC. Watch out for your local axis designation which varies in practically every program to make sure you're looking about the right axis.
Pn and Mn depend on the shape of your member, it's thickness, etc. Pn is going to be your axial resistance, which varies depending on whether your member is in tension and/or compression (compression considers buckling capacity, which your FEA program may or may not consider. Most do not unless you directly specify nonlinear effects and execute a nonlinear analysis command rather than a stiffness analysis).
Mn is your flexural resistance (Sx*Fy in its simplest form for capacity up to full yield). There are a lot of parameters that influence these values. Check out the chapters in AISC related to compression, tension, and Flexure (including commentary) for some further guidance.
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