18.13. Selection of Number of Modes

Try these first

1. 1.

   What is the typical number of modes required for low-rise structures?

   Hint

   Think about the height and complexity of the building.

2. 2.

   Name a type of irregularity that affects mode selection.

   Hint

   Consider how uneven shapes and distributions can impact a structure.

3. 3.

   What is the recommended number of modes for a high-rise building?

   • 3-4
   • 5-10
   • 15-20

   Hint

   Think about the height and dynamic characteristics.

4. 4.

   True or False: Irregular structures always require fewer modes to analyze.

   • True
   • False

   Hint

   Consider how irregular shapes affect stability.

5. 5.

   You are given a design for a mid-rise structure. Considering its asymmetrical layout, what considerations would you take into account for mode selection?

   Hint

   Reflect on how asymmetries might influence structural behavior.

6. 6.

   For a seismic analysis of a high-rise building, how would you justify the inclusion of 20 modes while addressing computational efficiency?

   Hint

   Think of balancing accuracy and computational constraints.