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URSmodeller
Posts: 8
Registered: ‎12-16-2011
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Footfall analysis result could not show RMS acceleration map?

735 Views, 9 Replies
01-04-2012 06:26 AM

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.

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pp2008
Posts: 475
Registered: ‎06-23-2008

Re: Footfall analysis result could not show RMS acceleration map?

01-04-2012 07:08 AM in reply to: URSmodeller

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

 

Regards,



Pawel Pulak
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Product Support
pp2008
Posts: 475
Registered: ‎06-23-2008

Re: Footfall analysis result could not show RMS acceleration map?

01-04-2012 07:36 AM in reply to: pp2008

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,



Pawel Pulak
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Active Member
URSmodeller
Posts: 8
Registered: ‎12-16-2011

Re: Footfall analysis result could not show RMS acceleration map?

01-04-2012 07:51 AM in reply to: pp2008

Ok, thanks lot.

 

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

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pp2008
Posts: 475
Registered: ‎06-23-2008

Re: Footfall analysis result could not show RMS acceleration map?

01-04-2012 09:12 AM in reply to: URSmodeller

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,



Pawel Pulak
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Active Member
URSmodeller
Posts: 8
Registered: ‎12-16-2011

Re: Footfall analysis result could not show RMS acceleration map?

01-10-2012 02:26 AM in reply to: pp2008

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.

 

 

 

 

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Product Support
pp2008
Posts: 475
Registered: ‎06-23-2008

Re: Footfall analysis result could not show RMS acceleration map?

01-10-2012 02:39 AM in reply to: URSmodeller

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,



Pawel Pulak
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Active Member
URSmodeller
Posts: 8
Registered: ‎12-16-2011

Re: Footfall analysis result could not show RMS acceleration map?

01-10-2012 02:52 AM in reply to: pp2008

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.

 

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Product Support
pp2008
Posts: 475
Registered: ‎06-23-2008

Re: Footfall analysis result could not show RMS acceleration map?

01-10-2012 04:08 AM in reply to: URSmodeller

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,



Pawel Pulak
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Active Member
URSmodeller
Posts: 8
Registered: ‎12-16-2011

Re: Footfall analysis result could not show RMS acceleration map?

01-10-2012 04:13 AM in reply to: pp2008

Hi Pawel,

 

Excellent, many thank you for the help.

 

 

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