Acceptable Safety Factor to be applied to Eigen Buckling

[strainstress]

Hello,

I am designing a structure comprising of bunch of beams welded together.
After applying the loads and performing linear eigen value buckling analysis I obtained a factor of FACT = 4.

I understand that eigen value buckling overpredicts the buckling strength of a structure. In that case, what should be an acceptable value of FACT to prevent buckling for a real world application.

Thanks
StressStrain

 

[PicoStruc]

This kind of analysis only used to get theorical elastic buckling load (Load applied inn your model / FACT).

In no way this kind of analysis mean that your structure is 'inelastically stable' or resistant enough to take the load.

 

[johnbridge231]

This is a linear buckling analysis, which only predicts the ultimate buckling load and the corresponding buckling mode of the structure.
More information (post-buckling stability etc) can be obtained using a 3rd order analysis which is of course very demanding regarding the required experience and knowledge on non-linear systems.

Analysis and Design of arbitrary cross sections
Reinforcement design to all major codes
Moment Curvature analysis

http://www.engissol.com/cross-section-analysis-design.html

 

[TXStructural]

I guess I'll ask an obvious question: is this a theoretical structure, or is it to be permitted and built?
I usually try to point out that one cannot apply AISC or ACI codes without observing the kludges and peculiarities of the code(s). Mixing first principles and code provisions is a path to trouble in some cases. The closer you get to an exact answer, the smaller the margins for error, and the more likely things will go wrong because of deficient construction practices, variation in loads, wear, corrosion, or other factors outside the theoretical design process.

 

[IDS]

The short answer is you should apply the provisions of the applicable design code, rather than trying to come up with your own factor of safety.

The video linked below provides some good background:

https://www.aisc.org/UploadedContent/OnlineVideoCourseFiles/Set_2/part1.html

Doug Jenkins
Interactive Design Services

http://newtonexcelbach.wordpress.com/