Foundation: Supports all the loads of the bridge

Why are different types of foundations chosen? 

• Soil Features
• Bridge Superstructure: part of the bridge that takes on the live load

Categories of Foundations:

• Deep Foundations
  • Usually used with softer soils
  • Often used on long-span bridges
• Shallow Foundations
  • Usually used with solid, well-compacted soils

Types of Foundations:

• Spread Footings
  • Shallow foundation
  • Mostly concrete
  • Contain two parts:
    • Stem
      • Vertical part that the bridge rests on
      • Transfers the load to the footing
    • Footing
      • Located underground
      • Evenly distributes the load over a large area

• Driven Piles
  • Deep foundation
  • Utilize friction
  • Long shafts go into the ground to support the bridge
  • Commonly made of concrete, timber, or steel

• Drilled Shafts
  • Deep foundation
  • A deep hole is drilled into the ground and it is filled with concrete deep enough to reach strong soils

References: https://www.bridgeofflowersmass.org/tufts-bridge-foundations

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