Footfall Analysis - no results

[Anonymous]

Hi,

I've been running numerous footfall analyses and I have a couple of questions.

1. Every now and again, when I add or take out geometry, the model will run, though with no results shown for the footfall analysis. I then change the geometry back and it works again fine. Strange! No error messages or anything....

2. In order to get an accurate response factor, do you need to convert additional dead load cases to mass? Similar to running a modal analysis

3. Should there also be a modal case in addition to the footfall set up?

Thanks.

Ben.

[Artur.Kosakowski]

1. Every now and again, when I add or take out geometry, the model will run, though with no results shown for the footfall analysis. I then change the geometry back and it works again fine. Strange! No error messages or anything....

Could you attach model where there are no results for footfall?

2. In order to get an accurate response factor, do you need to convert additional dead load cases to mass? Similar to running a modal analysis

If they should be considered as masses then yes.

3. Should there also be a modal case in addition to the footfall set up?

No, it is not needed.

You may find the recording of the 12th Robot webinar helpful:

https://forums.autodesk.com/t5/robot-structural-analysis-forum/robot-structural-analysis-webinars/td...

[Anonymous]

Hi Artur, thanks for your reply.

I've attached the model that is currently working, and If you could please amend the inner stringer (see highlighted members attached) to a larger size (Say 430PFC) you will notice the results don't come up??

Model 1 is the model that works and Model 2 is the one that doesn't.

Thanks.

Ben.

[Artur.Kosakowski]

For the 2nd model there is only one eigenfrequency below 15Hz limit you set.

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.

[Anonymous]

Thanks Artur,

That makes perfect sense.

One more question is that when I add a column at the landing, the natural frequency increases, though my response factor also increases (transient). I'm wondering if you could explain this?

The SCI P354 document requires for stairs a response factor of <24, though it is not clear whether this is resonant, transient or both?

Regards,

Ben.

[Artur.Kosakowski]

I'm sorry but my knowledge of THA and SCI code is to limited to answer your question.