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william.snell
Posts: 4
Registered: ‎11-18-2013

Time History vs Footfall Response factor

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01-09-2014 05:34 AM

We've created two seperate models, one which runs a time history analysis, and another using footfall analysis for a simple beam.

 

When we calculate the response factor from the peak acceleration given by the time history analysis we get a response factor of 17.33 (see attached pdf of acceleration vs time plot for calculation method).

 

The footfall analysis for the same model gives a response factor of 8.

 

Could you please explain why we are seeing such a significant difference in the foot fall model?

 

Also, is it possible to see the peak acceleration from the footfafll analysis (not rms)? How is the rms calculated? Does it use the simplified coversion for a sin wave [a/sqrt(2)] or is it accurately calculated by integrating the accelerations?

 

Please find both model files attached.

 

Both models are following the SCI P354 procedure.

 

 

Thanks!

 

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