18.1. Basics of Structural Vibrations

Try these first

1. 1.

   What is free vibration?

   Hint

   Think about what happens when someone shakes a building and then stops.

2. 2.

   Define forced vibration.

   Hint

   Consider what happens to a building during an earthquake.

3. 3.

   What occurs during free vibration?

   • Continuous external force
   • No external force after disturbance
   • Irregular structural response

   Hint

   Think about shaking a structure and then letting it go.

4. 4.

   True or False: Natural frequencies are unique to each structure.

   • True
   • False

   Hint

   Consider how different types of buildings react uniquely to dynamic loads.

5. 5.

   A structure is designed with a natural frequency of 2 Hz. If an earthquake produces waves at 2 Hz, discuss the risks involved.

   Hint

   Consider how matching frequencies might compound the effects of dynamic loads.

6. 6.

   Consider a building designed with a specific distribution of mass across its floors. Discuss how uneven mass distribution could affect its natural frequency.

   Hint

   Think about how a seesaw might tilt differently depending on weight placements.