Engineering Design

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Engineering Design

• Presented by Licci A. Zizumbo

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Agenda

• Bridge Basics
• Forces Lab
• Who Builds BIG?
• Wonders of the World
• Bridge Challenge
• Computer Model
• Balsa Wood Model

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1, 2, 3s and A, B, Cs of Bridge Basics

• There are more than half a million bridges in the
  United States, and you rely on them every day to
  cross obstacles like streams, valleys, and
  railroad tracks. But do you know how they work?
  Or why some bridges are curved while others are
  straight?
• Engineers must consider many things -- like the
  distance to be spanned and the types of materials
  available -- before determining the size, shape,
  and overall look of a bridge.
• Since ancient times, engineers have designed
  three major types of bridges to withstand all
  forces of nature.

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The beam bridge...

• consists of a horizontal beam supported at each
  end by piers. The weight of the beam pushes
  straight down on the piers. The farther apart its
  piers, the weaker the beam becomes. This is why
  beam bridges rarely span more than 250 feet.

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Beam Bridge Forces

• When something pushes down on the beam, the beam
  bends.
• Its top edge is pushed together, and its bottom
  edge is pulled apart.

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The truss bridge...

• consists of an assembly of triangles. Truss
  bridges are commonly made from a series of
  straight, steel bars.

• The Firth of Forth Bridge in Scotland is a
  cantilever bridge, a complex version of the truss
  bridge.

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Truss Bridge Forces

• Every bar in this cantilever bridge experiences
  either a pushing or pulling force. The bars
  rarely bend. This is why cantilever bridges can
  span farther than beam bridges.

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The arch bridge...

• has great natural strength. Thousands of years
  ago, Romans built arches out of stone. Today,
  most arch bridges are made of steel or concrete,
  and they can span up to 800 feet.

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Arch Bridge Forces

• The arch is squeezed together, and this squeezing
  force is carried outward along the curve to the
  supports at each end. The supports, called
  abutments, push back on the arch and prevent the
  ends of the arch from spreading apart.

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Forces Lab

• Intro
• Forces act on big structures in many ways. View
  the examples that follow to explore the forces at
  work and to see real-life examples.

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Squeezing (Compression)

• Compression is a force that squeezes a material
  together. When a material is in compression, it
  tends to become shorter.

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Compression See It In Real Life

• The lower columns of a skyscraper are squeezed by
  the heavy weight above them. This squeezing force
  is called compression.

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Stretching (Tension)

• Tension is a force that stretches a material
  apart. When a material is in tension, it tends to
  become longer.

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Tension See It In Real Life

• The weight of the roadway and all the cars
  traveling on it pull on the vertical cables in
  this suspension bridge. The cables are in tension.

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Bending

• When a straight material becomes curved, one side
  squeezes together and the other side stretches
  apart. This action is called bending.

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Bending See It In Real Life

• The top side of the metal bar is pulled apart in
  tension, and the bottom side is squeezed together
  in compression. This combination of opposite
  forces produces an action called bending.

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Who Builds BIG?

• Civil Engineering 
• Mechanical Engineering
• Structural Engineering
• Electrical Engineering
• Environmental Engineering
• Architecture Geotechnical
• Engineering Construction Management

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Lets see what a few of them do

• Architects design structures -- from houses to
  soaring skyscrapers. All good architects must
  also have the ability to conceptualize and
  communicate their ideas effectively, both
  verbally and on paper, to clients, government
  officials, and construction crews.
• Civil engineers build cities -- from roads and
  bridges to tunnels, public buildings, and sewer
  systems. They are involved in the planning,
  construction, and maintenance of all kinds of
  structures. Creativity, civil engineers say, is
  the most important part of the job.

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Continued

• Structural engineers plan, design, and supervise
  the construction of facilities essential to
  modern life. They investigate the behavior and
  design of all kinds of structures, including
  dams, domes, tunnels, bridges, and skyscrapers,
  to make sure they are safe and sound for human
  use.
• Construction managers coordinate the entire
  construction process -- from initial planning and
  foundation work through the final coat of paint.
  Being a construction manager requires
  organization, attention to detail, ability to
  persuade, and an understanding of all aspects of
  the construction process.

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Wonders of the World
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George P. Coleman Bridge

• Location Yorktown, Virginia, USA
• Length 3,750 feet
• Type Movable (double swing span)
• The George P. Coleman Bridge is the largest
  double-swing-span bridge in the United States and
  the second largest in the world.

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Garabit Bridge, Massif Central, France

• Location Massif Central, France
• Completion Date 1884
• Length 1,853 feet
• Type Arch

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Akashi-Kaikyo Bridge

• Location Awaji-shima, Japan
• Type of Bridge Suspension Bridge
• Completion Date 1998
• Length 12, 828 ft
• Height 928 ft
• Cost 4.3 billion

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Sydney Harbor Bridge

• Location Sydney Harbor, Australia
• Type of Bridge Steel-arch bridge
• Completion Date March 19, 1932
• Length 1149 meters
• Height 134 meters
• Cost 13.5 million

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Bridge Challenge

• To test your engineering skills that youve just
  learned we are going to use West Point Bridge
  Designer 2005 to visualize and test a computer
  simulation of a bridge.
• After that, we are going to build our own bridge
  with Balsa Wood.
• So Lets Get Started!