Footfall analysis result could not show RMS acceleration map?

[Anonymous]

Hi,

please refer to attachement.

I have complete footfall analysis, it appears only overall accelerations are avalaible in map, but RMS values.

Please can you advice?

Many thanks.

[Pawel.Pulak]

Can you attach the model - saved without results and compressed to ZIP to reduce the size.

Regards,

[Pawel.Pulak · Accepted solution]

Hi,

attaching your file seems not necessary. I have checked it and Mean aRMS is not calculated for the following provisions:

"Concrete Centre (2006) slabs" and "AISC DG11 (2003) floors" because it is not required by them. See the attached screen captures. It is calculated for the other ones.

See also:

http://docs.autodesk.com/RSA/2012/ENU/filesROBOT/GUID-3AD2F89E-BA01-415F-80C5-C83E3902A47-733.htm

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Regards,

[Anonymous]

Ok, thanks lot.

If robot can also give RMS acceleration map before it be converted in to response factor would be handy.

[Pawel.Pulak]

RMS acceleration map is displayed for SCI P354 provisions because it is used there (see the attached screen capture). Would you like something more?

Regards,

[Anonymous]

Hi Pawel ,

Thanks for your help.

One last question, for the concrete centre method, is overall maximum acceleration is sum of peak values from each harmonic or square-root sum of square?

Thanks.

[Pawel.Pulak]

As written in the help topic mentioned by me before (http://docs.autodesk.com/RSA/2012/ENU/filesROBOT/GUID-3AD2F89E-BA01-415F-80C5-C83E3902A47-733.htm) it is calculated as the square root of the sum of squares):

The response factor for the harmonic component h:

Calculate the overall response factor for the resonant response analysis as a square root of the sum of squares of 4 response factors for the harmonic components.

Regards,

[Anonymous]

Hi Pawel,

Thanks your swift response.

My question is about "overall max a" not response factors. For clarification, please refer to attached pics and extract from your help doc. below.

"You can select the following maps in the dialog:

·      maximum response factors (for the resonant and transient response analyses)

·      mean velocities (RMS, RMQ)

·      acceleration (overall maximum, mean aRMS).

The mean acceleration value aRMS (Root Mean Square) is:"

Cheers.

[Pawel.Pulak · Accepted solution]

Hello,

for "overall max a" it is the same - it is calculated as SRSS combination of accelerations of harmonics.

See the attached screen capture confirming it - especially the table below footfall analysis diagrams.

sqrt(4.7*4.7+2.8*2.8+0.7*0.7+10.9*10.9)= 12.2 mm/s2

Regards,

[Anonymous]

Hi Pawel,

Excellent, many thank you for the help.