Seismic Result

[MohammadZaman]

Hi 

I think the robot structure has an  error in seismic calculation .

Could you please help me to understand this result. For seismic loading in according with UBC97 the program has calculated wrong values .Vx= 0 and Vy= 29.63 t !!!! . The Vx should be about 4.4 t .

[Artur.Kosakowski · Accepted solution]

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MohammadZaman wrote:

Hi 

I think the robot structure has an  error in seismic calculation .

Could you please help me to understand this result. For seismic loading in according with UBC97 the program has calculated wrong values .Vx= 0 and Vy= 29.63 t !!!! .

Please make sure that you define large enough number of modes in the modal case to include vibrations in the X direction. For this model you should increase them from 3 to 6 as shown on the attached picture. In addition the main mode for the direction X should be the 4th rather than the 1st.

 The Vx should be about 4.4 t .

For the parameters as described above the value of Fx displayed for the diagram for buildings is 6.01T. If you look at the value of reactions you can see that it is 4.52T which is what you would expect. The difference between these values is explained in the answer for your previous post (see http://forums.autodesk.com/t5/Autodesk-Robot-Structural/Seismic-Result/td-p/3101884).

If you find your post answered press the Accept as Solution button please. This will help other users to find solutions much faster. Thank you.

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[MohammadZaman]

Thank you very much