17.10. Seismic Excitation: Base Acceleration Input

Try these first

1. 1.

   What is ground acceleration and why is it important in structural analysis?

   Hint

   Think about what happens to buildings during earthquakes.

2. 2.

   Define modal coordinates.

   Hint

   Consider how we break complex motions into simpler components.

3. 3.

   What does ground acceleration measure?

   • Displacement
   • Force
   • Acceleration

   Hint

   Consider what happens to the ground during seismic events.

4. 4.

   True or False: Modal coordinates allow us to analyze multiple vibration modes at once.

   • True
   • False

   Hint

   Think about how we break down complex systems.

5. 5.

   Analyze a 5-story building under ground excitation with specific mass and stiffness values. Calculate its modal participation factor after applying transformations to modal coordinates.

   Hint

   Remember the steps of eigenvalue calculation and transformation.

6. 6.

   Critically evaluate a design approach for a structure based on low modal participation factors from a seismic standpoint. What precautions should be taken?

   Hint

   Think about the implications of neglecting certain modes.