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I was working on seismic design of steel structure.
There are two methods for linear seismic analysis
1. Lateral force method and
2. Modal response spectrum analysis
Now my structure is not satisfying all criteria for both methods i.e.,
First mode of vibration criteria is satisfied for 1 st method while regularity criteria is satisfied for 2 nd method.
So I am confused which method Shall be used.
Please guide me.
I'm new guy in seismic engineering so I have a question.
1) After calculating the eigenvalues I get structures frequence, period and base shear. The structure is in low seismic zone ( 0.9 m/s2) but really windy. So do I need to check wind base shear? In one example I find out that they are comparing base shear from wind and seismic base shear and take the most dangerous from them to each floor. That base shear they transmit to each floor but not to the RC shaft (the wind or seismic base shear). After that they are looking for displacement. So that is the correct way to look for displacement from seismic action? Do I need to look from eigenvalues or from base shear? Each eigenvalue gives me a lot bigger displacement compare to results from base shear from seismic and wind base shear maximum value. And how to calculate the max displacement for the structure?
The structure is 5 story precast concrete building.
I'll start a design of a concrete building according Eurocodes. All foundations will be pad / isolated.
I have some questions about foundation design.
1. Have all foundation to be at one level in seismic region?
2. How much could be the eccentricity relative to the foundation size?
Thank you in advance