the building model is following Eurocode EC8. The query is that by increasing the value of behavior factor, will the roof displacement of the model will decrease or increase?
Higher q value will lead to smaller force and lower displacements in elastic calculation, however real displacement is obtained by multiplying elastic displacement with q.
Tareq Hatahet Sir, can you share any formula having both parameters, behavior factor and horizontal force. I want to understand the relationship of both the parameters. Kindly acknowledged.
Jacint Virag Sir, for real displacement if I multiply elastic displacement with q then by increasing q factor, the real displacement will also increase? right? If yes then Sir according to you higher q factor lead to smaller displacement would be invalid. Sir, Can you explain a bit more. I am just confused. thank you
in Romanian code
Fb= (gamma) Sd(T) m (lambda)
where
Fb - base shear force
Sd(T) - design spectra, which is inverse proportional with the ductility factor q
m - the mass of building
(gamma) and (lambda) - correction factors
According to UBC97 and in specific the sub-clause (1630.9.2):
The maximum ''inelastic'' response displacement, Delta_m, shall be computed as follows:
Delta_m=0.7 * R* Delta_s.
Notations:
''0.7'' in order to convert from ultimate to serviceability limit state.
''R'' is the ductility factor which is equivalent to ''q'' in EC8.
''Delta_s'' is the elastic response displacement resulting from a static, elastic analysis of the lateral force resisting system using the design seismic forces (V=Cv*I*W/R*T).
Then accordingly increasing the ductility will lead to higher inelastic displacements.
(The equations may differ from code to code but the concept is the same!!).
Relation is nonlinear (or min. bilinear), and solution is therefore iterative. You can only defend your q value by proper pushover Analysis which is the equation that you are Looking for, clear it depends on the str. sys. The Code gives some guide to save you this effort.
Strutures are expected to response inelastic, therefore the Purpose of the q factor is to predict equivilant static load for ULS Control.
For displacement Control then you corect the elastic displacement as the gents explained earlier.
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