Earth Quake load

Question

Please, show me file help step by step Calculate Earth Quake load. I have opened 2 trainning file "Balanced-Cantilever" and "Earthquake" but I am not clear. 
 In training file"Balanced-Cantilever", Earth Quake load been calculated the Response Spectrum Analysis, but Load define Earth quake is blank 
 
 In training file"Earthquake, I saw file "eigen.mod". 
 " 
 Please, explain me. Is that 2 way Calculate Earth Quake load by the Response Spectrum Analysis method? 
 Thank you so much.

Diether · Accepted Answer

Hi phancongoanh, 
 For response spectrum analysis please refer to the Training Example 05. Earthquake EC . 
 It contains an detailed step-by-step documentation of how to introduce Response Spectrum Analysis (and Time History Calculation as well). 
 The other example "Balanced Cantilever" only uses a statical earthquake load using standard load case definition (self-weight applied in longitudinal and transverse direction). 
 Regards, 
 Diether

Pedro Natário · Answer

Hello phancongoanh, 
 
eigen.mod is a file that you may obtain after you process the eigenvalue calculation, i.e. the modal analysis where you obtain the frequencies and shapes of each mode. In order to obtain eigen.mod or xxx.mod (you decide the name of the file), you need to perform the EIGEN action in a stage. As input, you need to define the number of modes you want to calculate (usually you are looking to obtain a mass participation of over 90%) and the load case where you have defined the masses (the stiffness will be calculated by RM Bridge based on your structural input). 
 
In your second image, you already have the modes listed in the eigen.mod file and you combine them with the response spectrum or any other function (that's the Var-Name(Graph) column) representing the soil displacent/velocity/acceleration that you have previously defined in a table in Properties/Variables. 
 
Hope this helps you...

Earth Quake load

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