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Footfall Vibration Results Inconsistencies

Message 1 of 3
384 Views, 2 Replies

Footfall Vibration Results Inconsistencies



I have made a typical slab model to run the vibration analysis and get the response factor plots. The outputs from the analysis suggest some areas of slab have a response factor of 0 and are therefore not at all excited which does not correlate with my deflection plots. I would expect response factor values almost everywhere except some very stiff points such as at columns and wall positions. Do you have any idea why these are not shown? I have attached screenshots and the model. I have also tried making the floor plate one big panel to see if this was the issue but the same problem persisted.


Best regards,


Message 2 of 3
in reply to: Anonymous

Looking at the results it can be seen that values are not zeros but just very small and IMHO they correspond to shapes of vibrations. You may try to reduce the size of the outer ring beam to see if it has got any influence.


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Artur Kosakowski
Message 3 of 3
in reply to: Artur.Kosakowski

Hi Artur,


Thanks for your response.


I think it also had to do with the frequency limit in the parameters of the footfall analysis. As the default is 15Hz and my slab is very stiff, it was only showing the RF associated to the modes below that frequency. When I increased it, it gave me more uniform results.


Best regards,


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