Question
How to create artificial earthquake for time history analysis?
Answer
The "Artificial Earthquake Generator" feature allows the creation of artificial seismic waves for time history analysis.
1. Method to generate artificial seismic waves
1) Go to the Tools menu and select Data Generator > Artificial Earthquake Generator.
2) Click on "New" and select "Model" to open the Add/Modify Artificial Earthquake window.
3) Click on "Design Spectrum" and choose the criteria and conditions for generating the earthquake wave.
4) Enter the seismic risk factor and seismic zone coefficient, and input the maximum period that covers the analysis range of the structure's eigenvalues.
5) Click the OK button to generate the design spectrum.
6) The rise time, duration, and total time should be determined based on the KDS 17 10 00 general criteria for seismic design. Input the values that correspond to the seismic intensity being evaluated.
For example, for an intensity of magnitude 7.2, the input rise time is 2 seconds, the duration is 12.5 seconds, and total time as 28 seconds.
7) Set the number of iterations for convergence assurance and enter the maximum acceleration (obtained by multiplying the hazard coefficient and seismic zone coefficient). (The number of iterations is typically set to 20.)
8) Use the damping ratio of 5% as specified in KDS 17 10 00 for the standard design response spectrum.
9) Check the "Random Seed" box and input a random value between 1000 and 1500. (This is the number of random seeds used for generating random phase angles. It is recommended to input an odd number between 1000 and 1500.)
10) Click the "Generate Acceleration" button.
11) Change the graph type to acceleration graph for time history analysis, and use the "Data Export" function to save the artificial earthquake wave at the desired location.
2. Method to import the generated artificial earthquake wave in Civil
1) Go to the "Load" tab and select "Dynamic Loads". This will open the "Time History Functions" window.
2) Click on "Add Time Function" to open the "Add / Modify / Show Time History Functions" dialog.
3) Click on the "Import" button to load the generated artificial earthquake wave.
4) Click "OK" to add the artificial earthquake wave.