MEPX
Chapter 3 of 12All chapters
  1. 1What engineers do
  2. 2The design process
  3. 3Forces and loads
  4. 4Stress, strain and materials
  5. 5Structures
  6. 6Mechanisms
  7. 7Electrical basics
  8. 8Energy in machines
  9. 9Manufacturing and tolerances
  10. 10Safety factors and failure
  11. 11Testing and standards
  12. 12Responsibility

Chapter 3 of 12

Forces and loads

What a structure has to survive.

Kinds of load

Dead load is the permanent weight of the structure itself. Live load is what changes: people, vehicles, snow, wind. Dynamic loads add movement, which is far harder than the same force applied slowly.

  • A load applied suddenly can do more damage than a larger one applied gently.
  • Repeated loading causes fatigue, which breaks things well below their rated strength.

Statics

If something is not moving, all the forces and all the turning effects on it cancel. That single statement lets you solve for unknown forces in most structures.