Science Finals

• Types of loads


  • Dead load
  • Shock load
  • Environmental load
  • Live load
• Dead load


  Weight of the bridge
• Shock load


  Trains and heavy trucks crossing the bridge
• Environmental load


  Environmental factors
• Live load


  Weight of the traffic crossing the bridge, creates downward force
• Things to consider when designing a bridge

  • Load
  • Forces
  • Materials
• Most important forces affecting bridges

  • Compression
  • Tension
• Materials strong under tension

  • Rope
  • Wood
• Materials strong under compression

  • Wood
  • Reinforced concrete
  • Steel
  • Some plastics
• Arch bridge


  Uses a semi-circular design
• Cable-stayed bridge


  Best for long distances, uses counter-acting forces by cables on both sides of towers
• Truss bridge


  Can accommodate dynamic loads
• Beam bridge


  Good over narrow distances, can support its own weight and load on piers
• Suspension bridge


  Works well in earthquake zones
• Bascule bridge


  Allows passage and can be prefabricated
• Cantilever bridge


  Has no direct under supports
• Cable-stayed bridge


  Uses triangle shapes in its design
• Cantilever bridge


  Extremely safe and secure
• Truss bridge

  Can make a good temporary bridge
• Some of the longest bridges are suspension bridges