Historical developments of civil structures

Overview

  • Many of the innovative civil structures were originally developed with material use and production limitations.
    • The first bridges were simple timber spans, made from wood and twine.
    • Later bridges were from stone and other variations, which required masonry etc.
    • During the Industrial Revolution (1750-1830), wood and stone soon were replaced by steel.
  • Most of the techniques used in construction was developed through trial and error which eventually led to the recognition of structure/property relationships of the materials.
  • Over time, guidelines were developed and standards such as material testing, processing, design and tech drawing conventions began to occur. Leadingt to spread of techniques throughout the engineering community.

Bridges

Beam Bridges

  • Simplest type of bridge.
  • A beam is a member that is supported so that its supports don't carry any longitudinal forces.
  • In addition, trusses are a type of beam, thus a variety of truss bridges count as beam bridges.
  • There are two types of beam bridges:
    • Cantilevered Beam: This is when a beam is only supported at one end.
      • As a result, if a force acts on the from the top, the top would be in tension and the bottom would be in compression
    • Simple Supported Beams: This is when a beam is supported at both ends.
      • As a result, if a force acts on the from the top, the bottom would be in tension and the top would be in compression
  • Early Beam bridges date back to the Romans, which used multi-span stone bridges.
  • By the 16th century, a truss girder bridge had been developed in Italy and by the 19th century, truss girder bridges became widely used in railway systems.
  • The most commonly used truss girder bridge - the box girder - was developed in the mid-20th century.

Arch Bridges

  • Quite a simple type of bridge
  • Developments in it occured as new materials were made available.
  • Used extensively by the Romans back in 200 BC with Masonry Arch Bridges.
  • The introduction of Cast Iron in bridges in the 18th century led to few cast iron bridges.
  • Steel Arch Bridges came about in the early 20th century in America.
  • Now, arch bridges are rarely used but most modern ones are concrete arches.

Suspension Bridges

  • Suspension bridges are ones that support the deck on tension members between support towers.
  • Long long time ago, suspension members for these bridges included vine and twine.
  • Later in the 19th century, wrought iron chains were used instead once production was available in commercial quantities.
    • Yet, most builders around this time lacked the technique to build these bridges.
    • It wasn't until the late 19th century that the technique became usable.
  • Steel soon became the ultimate tensile member for these bridges.
    • A famous one to remember is the Tacoma Narrows bridge, which failed spectacularly.