11.18. Base Shear Calculation in MDOF Systems

Try these first

1. 1.

   What does base shear refer to?

   Hint

   Think about the forces acting on a building during an earthquake.

2. 2.

   Why is calculating modal responses important?

   Hint

   Consider how different components might move.

3. 3.

   What is base shear?

   • A vertical force
   • Lateral force due to seismic activity
   • Gravity force

   Hint

   Consider what forces are acting sideways when an earthquake occurs.

4. 4.

   Is calculating base shear unimportant for structural designers? (true/false)

   • True
   • False

   Hint

   Think about the consequences of incorrect calculations.

5. 5.

   A three-story building experiences modal contributions of 80 kN, 120 kN, and 160 kN respectively. Calculate the total base shear and explain its significance in structural design.

   Hint

   Add the contributions together.

6. 6.

   Discuss how an engineer would approach adjusting the structural design if the calculated base shear for a proposed building exceeds expected values based on local codes.

   Hint

   What are some common techniques to strengthen buildings?