Hi all: According to the robot help manual
Base shear force is calculated according to the formula:
Fb = Sd(T1) * m * λ (4.5)
Sd(T1) - value of design spectrum of response for period T1 according to the point 3.2.2.5
m - total mass of the building according to 3.2.4(2)
λ - correction factor, (0.85 or 1.0) set automatically basing on the Clause 4.3.3.2.2
However I notices that the correction factor λ 4.3.3.2.2, is wrongly used by robot. I have done several models making sure that my
T1 is > 2TC (eg 1.6s on type B ground) but robot still uses 0.85 as λ. This result in wrong Total seismic base shear.
The last thing has to do with the value of Ct=0.05 for other structures. I have noticed a typo in the calculation report as the robot still records
a value of 0.09 for other structures this is very confusing. (this has to be corrected)
I will kindly need some clarification on the issues raised above.
Thank you.
Regards,
pok
Solved! Go to Solution.
Solved by Artur.Kosakowski. Go to Solution.
Solved by Artur.Kosakowski. Go to Solution.
Hi all is not just NBCC 2010 but also the EC8.
According to the robot help manual
Base shear force is calculated according to the formula:
Fb = Sd(T1) * m * λ (4.5)
Sd(T1) - value of design spectrum of response for period T1 according to the point 3.2.2.5
m - total mass of the building according to 3.2.4(2)
λ - correction factor, (0.85 or 1.0) set automatically basing on the Clause 4.3.3.2.2
However I notices that the correction factor λ 4.3.3.2.2, is wrongly used by robot. I have done several models making sure that my
T1 is > 2TC (eg 1.6s on type B ground) but robot still uses 0.85 as λ. This result in wrong Total seismic base shear.
The last thing has to do with the value of Ct=0.05 for other structures. I have noticed a typo in the calculation report as the robot still records
a value of 0.09 for other structures this is very confusing. (this has to be corrected)
I will kindly need some clarification on the issues raised above.
Thank you.
Regards,
pok
What is the number of the stories in your model? Could you attach it?
Hi Artur,
I think the answer on your first question is shown in the attached pictures (model 1 ->14stories, model 2 -> 24stories)
However I notices that the correction factor λ 4.3.3.2.2, is wrongly used by robot. I have done several models making sure that my
T1 is > 2TC (eg 1.6s on type B ground) but robot still uses 0.85 as λ. This result in wrong Total seismic base shear.
As your model seems to have more than 2 stories could you attach it please?
The last thing has to do with the value of Ct=0.05 for other structures. I have noticed a typo in the calculation report as the robot still records
a value of 0.09 for other structures this is very confusing. (this has to be corrected)
I have asked the development team to investigate this situation. Thank you for reporting it.
Thank you.
Regards,
pok
Hi Arthur,
I have attached the two models without results as you requested.
And a quick comment, this error is been repeated in the 2015 version.
Please you and your crew should do something about it.
Thank you.
Thank you for the files. The issue is under investigation.
The correction is planned for SP2 for Robot 2015.
Please note: Our quality assurance teams may need to reschedule some fixes. Please rely on the above timeline information as a guideline only and not a guarantee. We appreciate your understanding in this matter.