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Ratio of loads: Long-term to variable Creep coefficients

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10-29-2012 07:25 AM

Hi,

 

Looking at the SLS paremeters for slab analysis.  I have a few questions.  I am used to utilising SAFE for deflection analysis of my flat slabs; however I am intrigued about the capability of ROBOT to offer a complete design solution. 

 

I note that in the BS8110 reinforcement parameters a "ratio of loads:long-term to varaible" value can be edited. 

 

Is there any way of assigning the long term/short term to a specific load?  and also is there a mothod of attributing a certain percentage of a certain loading case to long term or short term laoding parameters.  I.e. could I attribute 20% live as long term sustained loading and 80% to instantaneous short term loading? 

 

Many Thanks,

 

Andrew

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Registered: ‎04-26-2010

Re: Ratio of loads: Long-term to variable Creep coefficients

10-29-2012 07:35 AM in reply to: esuffk

See below

 

bs8110.jpg



Rafal Gaweda
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Registered: ‎09-18-2012

Re: Ratio of loads: Long-term to variable Creep coefficients

10-29-2012 07:43 AM in reply to: esuffk

Presumably, if I set 30% of load to be be long term sustained then this will result in all of the loading in the SLS combination being treated as long term?

 

Do I need to manually go through my unfactored loads and calculate how much of it needs to be long term?  What happens is I am to expect some long term live in one area an not another? 

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Registered: ‎04-26-2010

Re: Ratio of loads: Long-term to variable Creep coefficients

10-29-2012 07:58 AM in reply to: esuffk

esuffk wrote:

Presumably, if I set 30% of load to be be long term sustained then this will result in all of the loading in the SLS combination being treated as long term?

 

http://docs.autodesk.com/RSA/2013/ENU/index.html?url=filesROBOT/GUID-B7AE54EB-BB4F-4DC9-97C4-79AA213...

 

You can also determine the ratio of variable loads to long-term loads.

Variable loads may be divided into short-term and long-term loads. The long-term to variable coefficient specified in the Ratio of loads is used to split variable loads into a short-term part and a long-term part according to the following formula.

variable load = (1 - c) * variable load + c * variable load = short-term load + long-term load,

where c is a coefficient of the participation of long-term loads in variable loads.

 



Rafal Gaweda