Optimization in Serviceability

[M.Christensen1988]

Hey

I'm trying to optimize a structure in the Steel/Aluminium Design.

The problem is, when i try to optimize it in serviceability. I have defined the displacement values in final deflection and Node displacement. It has no problems in optimizing the members in final deflection , but all it does in Node displacement is telling me that the members aren't big enough... it wont optimize them for me.

As you see in the picture below, it says in Code Group Design is okay, but in the Code Group Verification it has added "case(vx)" and "case(vy)", where the ratios are greater than they are allowed. Is there anyway i can get it to optimize it in Code Group Design as it does for the "Case(uy)" and "Case(uz)"?.

I have altered the entire fram manually to lower the ratios, but I would like Robot to do that for me as there is quite a few frames to do it for.

so, to sum up. Is there anyway to get Code Group Design to optimize for "Case(vx)" and "Case(vy)"?

[Pawel.Pulak · Accepted solution]

Serviceability optimization for node displacement of columns is not available because in huge majority of structures the section (and stiffness) of some column is not the main factor influencing lateral displacements of top node of this column. Much more visible is the influence of shear walls or bracings defined in the structure. In case of unbraced frames lateral displacements of some column are influenced not only by stiffness of this column but also by other columns. That is why optimisation of node displacement cannot be done in simple way.

Serviceability optimization for deflection of beams is available because in this case there is quite direct relation between section (and stiffness) of some beam and its deflection. That is why algorithm suggesting appropriate section of beam can be effective.

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Best regards,