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Load to mass conversion
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Dear Sir
- Which mass type (global mass & dynamic mass ) shall I use it for my model (concrete tower 21 floor )?
- Shall I activate the mass in three directions (X,Y,Z) or only (X,Y) Because my building height = 75m ?
Thanks in advance
Refaat
Solved! Go to Solution.
Re: Load to mass conversion
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Most accurate is consistent I believe. But we normally use lumped with rotations.
If you disregard density there will be no mass participating in the modal analysis. Unless you add it back in via load to mass conversion.
I would NOT disregard density, and also add 30% live load (or whatever percentage) to the load to mass conversion. Normally can ignore Z direction. If you add mass to global or dynamic the mass will be added to all dynamic cases. If you specify the modal case only, it will only be added to that case.
Re: Load to mass conversion
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Refaat
- Which mass type (global mass & dynamic mass ) shall I use it for my model (concrete tower 21 floor )?
http://forums.autodesk.com/t5/Autodesk-Robot-Struc
tural/Conversion-load-to-mass/m-p/3050232/highligh - message 3...
Rafal Gaweda
Re: Load to mass conversion
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Dear Sir
I got confused about base shear coeff. ( as i see in the attached capture 01) you got this coeff. (1.74) by dividing (automatic / inactive ). Did you mean that the inactive case is the static linear case ?? (because as we know that the base shear scale is the ratio (0.85Vstatic/Vdyanmic) . as I used it in the capture 02 ,is it true or not ?
Thanks
Refaat
Re: Load to mass conversion
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Dear Sir
Pls , give me more explanation ( 3 Selecting Global mass - converted masses will be applied to all dynamic cases and also can be used in inertia forces (of course if such forces are applied on model)
In my case , I will use (global mass ) in my model is Keya ?
Thanks
Refaat
Re: Load to mass conversion
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Pls , give me more explanation ( 3 Selecting Global mass - converted masses will be applied to all dynamic cases
Example:
Rafal Gaweda
Re: Load to mass conversion
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Refaat,
I got confused about base shear coeff. ( as i see in the attached capture 01) you got this coeff. (1.74) by dividing (automatic / inactive ). Did you mean that the inactive case is the static linear case ??
Inactive means that results come directly from seismic calculation without base shear.
as I used it in the capture 02 ,is it true or not ?
Yes, true.
One more remark: do not use "Use normalized values" checkbox.
Rafal Gaweda
Re: Load to mass conversion
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Dear Sir
Do you mean that ( Dynamic = globle + modal ) ? , and i have to use dynamic
Thanks
Rrfaat
Re: Load to mass conversion
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Dear Sir
As appears in the attached capture
As I understand (T= structure period ) and what about (reduction coeff.)?
Thanks
Refaat
Re: Load to mass conversion
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Do you mean that ( Dynamic = globle + modal ) ? , and i have to use dynamic
Global means that converted masses will be considered in ALL dynamic cases in model (modal and footfall ones; other dynamic cases need to be run after modal case so they consider masses from precedent modal).
My advise: use dynamic.
Rafal Gaweda