You may try to define the load case with the gravity load above the given story (or delete the part below and replace it with supports) and check the value of the reactions for Ptot and check the values of horizontal forces for seismic case in the stories table for Vtot.
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In my opinion, the very important value of "θ" should be automatically calculated and displayed in the table of stories. This value is a similar one to that of EC3 in chapter 5.2 that is called "αcr" for which i have already post in the wish list:
Artur:
The corresponding to the proper load case value of Fz in Reduced forces that is displayed in the the table of stories (or viewed in Diagrams for buildings) isn't wat we need about Ptot in order to calculate "θ"? Why should we do that kind of approach that you mentioned ?
Are the values of displacements (U or dr) in the table of stories properly calculated for seismic load cases (i.e the calculated value obtained from elastic analysis multiplied with the defined value q)?
35058355, that is true in many cases (i suppose) but not in all Seismic codes (e.g in the Greek code: EAK2000/2003 this multiplication unfortunatelly isn't implemented in Robot for the dicplacements so i have it in mind in my calculations). It is o.k, for instance, when using EN1998-1-1:2004 ...
The corresponding to the proper load case value of Fz in Reduced forces that is displayed in the the table of stories (or viewed in Diagrams for buildings) isn't wat we need about Ptot in order to calculate "θ"? Why should we do that kind of approach that you mentioned ?
Simply I didn't think about such possibility writing the answer Thank you for finding the easier way.
Are the values of displacements (U or dr) in the table of stories properly calculated for seismic load cases (i.e the calculated value obtained from elastic analysis multiplied with the defined value q)?
These results are based on displacements of nodes. When q is included in the values of nodal displacements it is also included in this table.
in the Greek code: EAK2000/2003 this multiplication unfortunatelly isn't implemented in Robot for the dicplacements so i have it in mind in my calculations).
What is the way EAK code scales the displacements depending on the value of the behavior factor?
In principle of course yes but my understanding was the exact formulas are a bit different. Thank you for your answer.
Dear Artur,
The formulas used in EAK and EN1998-1 are exactly the same. It means that after the elastic analysis is perfomed by deviding the seismic forces with the factor q, the final and real (i.e inelastic) displacements obtained from elastic analysis must be multiplied with the same factor. In EN1998-1, there is a note that mentions the cases when the funtamental period is less that Tc where the multiplication factor should be slightly bigger than q. In EAK, the case of T<Tc is covered without changing the multiplication factor because the effect of it is already accounted in the responce spectrum.
In Robot when EAK is used, the values of final displacements are changing with the change of "q" but they should remain the same. In EN1998-1 the displacements are indeed the same after changing the q value.
Thank you for the clarification. I have added the request for EAK behavior factor being taken into account for displacements to the wish list.
Thank you for the clarification. I have added the request for EAK behavior factor being taken into account for displacements to the wish list.
Implemented in Robot 2015.
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