30.2. Definition of Spectral Acceleration (Sa)

Try these first

1. 1.

   Define Spectral Acceleration (Sa).

   Hint

   What does Sa measure?

2. 2.

   What are the units of Spectral Acceleration?

   Hint

   What do we use to measure acceleration?

3. 3.

   What does Spectral Acceleration (Sa) represent?

   • Peak ground acceleration
   • Maximum acceleration of SDOF system
   • Average acceleration over time

   Hint

   Think about the definition of Sa.

4. 4.

   True or False: Higher damping ratios increase spectral acceleration.

   • True
   • False

   Hint

   Consider how structures behave with different damping levels.

5. 5.

   A structure with a natural period of 0.5 seconds is subjected to an earthquake with a spectral acceleration of 0.6g. If its damping ratio is increased from 5% to 15%, predict the implications on its performance during an earthquake.

   Hint

   Consider how damping affects maximum acceleration response.

6. 6.

   Evaluate the effect of a varying damping ratio from 0% to 30% on spectral acceleration for a structure with a set natural period. Explain the trend observed.

   Hint

   What do you notice as you increase damping ratio?