Hi,
I'm designing a portal frame to BE EN 1993-1. My rafters fail the global stability checks for buckling resistance and bending & axial compression. I think the problem is in the calculation of chi LT (XLT in robot). Robot gives me values of XLT=0.18, while my hand cals show XLT=0.975. I attach my full calcs note
Any ideas would be greatly appreciated. Thanks
Hi @Anonymous ,
Could you please also attach your hand calculations?
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Roman Zhelezniak
Robot Evangelist & Passionate Civil Structural Engineer
Hi Romanich,
My calculated XLT was actually 0.952, but still much higher than the one calculated in robot. See attached
Hi @Anonymous ,
Mcr and lateral buckling curve are different. Have you tried to input these values manually and check the results?
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Roman Zhelezniak
Robot Evangelist & Passionate Civil Structural Engineer
Hi @Anonymous ,
Could you please attach your Robot model?
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Roman Zhelezniak
Robot Evangelist & Passionate Civil Structural Engineer
Hi @Anonymous ,
Try to zip model first or check this topic
https://forums.autodesk.com/t5/robot-structural-analysis-forum/sending-bigger-files/td-p/3795062
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Roman Zhelezniak
Robot Evangelist & Passionate Civil Structural Engineer
Hi @Anonymous ,
Also I would kindly recommend to always check warnings:
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Roman Zhelezniak
Robot Evangelist & Passionate Civil Structural Engineer
Thanks @Romanich
I'm still a bit confused with all the lengths that need to be specified (Ly; Lz; Lcr,y; Lcr,z; Lcr,low) and how they are taken into account in calculations. Are there any guidelines on how buckling calcs are dealt with in Robot?
I.e. I've changed Lcr,low to =1.64m, beta to =0.75, lambda lt,0 to =0.4 as you suggested and I'm still getting different (than my hand calcs Mcr=1588) value for Mcr=4300.
Warnings were due to the haunch specified in the model, I have deleted it now.
Hi @Anonymous ,
Please also check these topics:
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Roman Zhelezniak
Robot Evangelist & Passionate Civil Structural Engineer
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