Dataset#1: Poly Wants a Bridge!

Directions: Use the information from the charts below to complete your activity.

This chart contains information regarding several types of bridges. The “Physical Composition” refers to the materials out of which the bridge is made. The “Span Range” indicates the range of lengths from the shortest known bridge to the longest of that type. The “History and Uses” section contains information regarding the bridge’s uses as well as some of its advantages and disadvantages.

Type of Bridge / Physical Composition / Span Range / History and uses
Arch Bridge / Stone, brick, iron, steel, concrete / Short
150’ – 200’ /
  • allows great amounts of flood water to pass under it, which would prevent the bridge from being swept away during floods and the bridge itself could be more lightweight.
  • carries pedestrians, automobiles, trucks, light/heavy rail, water

Girder / Iron, steel, concrete / Short to medium
50’ – 900’ /
  • most commonly built and utilized bridge in the world.
  • Its major use isto carries pedestrians, automobiles, trucks, light/heavy rail.

Truss / wood, aluminum, steel, concrete / Short to medium
400’- 1600’ /
  • used to separate rail from road traffic or to separate the two directions of automobile traffic and so avoiding the likelihood of head-on collisions.
  • Not commonly used today due to cost
  • carries pedestrians, pipeline, automobiles, trucks, light/heavy rail

Cantilever / Steel, concrete, iron / Medium
1500’ – 3300’ /
  • continuous across multiple supports, which result in lower stresses on the beams and longer spans could be built
  • carries pedestrians, automobiles, trucks, heavy rail

Cable-Stay / Steel cables, concrete / Medium
750’ – 2000’ /
  • carries pedestrians, bicycles, automobiles, trucks, light rail

Movable (Draw) / steel / Short
Up 140’ /
  • lower cost, due to the absence of high piers and long approaches
  • must be halted when it is opened for passage of tall boats and ships
  • carries pedestrians, bicycles, automobiles, trucks

Suspension / Steel cables, irons links / Medium to long
1500’ – 7000’ /
  • carries pedestrians, bicycles, livestock, automobiles, trucks, light rail

Chart 1

The chart below contains information regarding the strengths and weaknesses of the materials used in building bridges.

Type of material / Strengths / Weaknesses
Wood / Cheap, lightweight, strong in compression and tension / Rots, swells, burns easily
Aluminum / Lightweight, doesn’t rust, strong in compression and tension / expensive
Brick / Cheap, strong in compression / Heavy, weak in tension
Concrete / Cheap, fire proof, weather proof, molds into any shape, strong in compression / Cracks with temperature changes, week in tension
Steel / Strong in compression and tension / Loses strength in extremely high temperatures

Chart 2