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Bridge Building

Page history last edited by kirish43@... 5 years ago

 Bridge Building

Truss Bridge Structure in GR MI

 

 

 

 

 

 


 Bridges are consructed to help us go over a river, chasm, road, or the like.

 

 

Bridge Basics

Because of the wide range of structural possibilities, this Spotter's Guide shows only the most common fixed (non-movable) bridge types. Other types are listed in the Bridge Terminology page. The drawings are not to scale. Additional related info is found on the other Terminology pages which are linked to the left.

The four main factors are used in describing a bridge. By combining these terms one may give a general description of most bridge types.

  • span (simple, continuous, cantilever),
  • material (stone, concrete, metal, etc.),
  • placement of the travel surface in relation to the structure (deck, pony, through),
  • form (beam, arch, truss, etc.).

The three basic types of spans are shown below. Any of these spans may be constructed using beams, girders or trusses. Arch bridges are either simple or continuous (hinged). A cantilever bridge may also include a suspended span.

simple spans

 

http://pghbridges.com/basics.htm 

 

Step #1 Planning = Let's find an area that needs a bridge.

 

Click on  Google Earth- Let's fly around the plant and look for a river chasm or road that looks like a bridge should be constructed their to help the people in the area.

 

a. What Latitude and Longatude is your area located at?

b. What types of materials should you construct your bridge out of?

c. Is there an easy way to get the materials to the site?

 

 


 

#2 Making reasoned choices...

Which Type of Bridge is the best suited for your area?

Study each type and then decide the kind of bridge you wish to construct.

The biggest difference between the types pf bridges is the distances they can cross in a single span. A span is the distance between two bridge supports, whether they are columns, towers or the wall of a canyon.

 

 

 Types of Bridges


 

Basic  Types  of  Bridges

Types of Bridges

 

Arch

Beam

Cable-Stayed

Cantilever

Suspension

Truss

 

Online Interactives

bUILD A RAILROAD BRIDGE- 10 levels

http://www.learn4good.com/games/building/bridge-engineering.htm

 

Blue Print Bridge designer with nodes and members

http://www.learn4good.com/kids-games/simulation/build_bridge_across_canyon2.htm

 

Build the Bridge

Your goal is to use the pieces provided to create a safe path for the train to travel across to the tunnel.

Pick up pieces with your mouse (drag and drop.) You can rotate pieces be holding them up in the air and using the arrow keys to rotate them.

When you are ready, hit the "play" arrow to start the train

http://www.coolmath-games.com/0-build-the-bridge

 

Physics Games - Bridge Builder

www.physicsgames.net/game/Bridge_Builder.html

Another bridge-building puzzler. Use beams and suspension cables to construct a bridge that will allow the truck to reach the checkered flag.

 

Bridge Craft

http://www.candystand.com/play/bridgecraft

 


 

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Bridge Designer

Actually this program allows you design trusses. Trusses are composed of straight members connected at their ends by hinged connections to form a stable configuration. When loads are applied to a truss only at the joints, forces are transmitted only in the direction of each of its members. That is, the members experience tension or compression forces, but not bending forces. Trusses have a high strength to weight ratio and consequently are used in many structures, from bridges, to roof supports, to space stations.

In this simulation, trusses are created by attaching members to nodes (joints). First, nodal locations are specified; then the nodes are linked by members to create a structure. Once the structure is established, two of the nodes must be assigned as support nodes. One must be a "fixed" node, i.e., one that can provide support in both the x- and y-directions; the other must be a "rolling" node, one that can provide support in only the y-direction. Finally, one or more nodes can be assigned to bear loads. http://www.jhu.edu/virtlab/bridge/bridge.htm

 

 

 

 

 

http://www.learn4good.com/games/simulation/build_bridge_across_canyon.htm

 

http://www.candystand.com/play/bridge

 

http://www.luckygamez.com/related/Bridge-Builder

 

http://www.smart-kit.com/s3052/bridge-building-game/


 

 

Bridge Building Facts and Tips


 

http://library.thinkquest.org/J0113129/DB~1.HTM

 

 

 

http://www.pbs.org/wgbh/buildingbig/bridge/basics.html

 

 

 Which Bridge Goes Where?

 

 

http://www.pbs.org/wgbh/nova/bridge/build.html

 

How do we use the West Point Bridge designer program

 

 


 

#3 How do we Build them?


 

Check Out the timeline of the Brooklyn Bridge

 What important things do we need to consider?

 

 Bridges need to deal with the important forces called compression and tension. Compression is a force that acts to compress or shorten the thing it is acting on.. Tension is a force that acts to expand or lengthen the thing it is acting on.

 

 

YouTube plugin error

 

What stressed acted upon this bridge that made it fail? 

 

Close up Structure

 

http://pghbridges.com/basics.htm

 

 

 

http://www.bardaglea.org.uk/bridges/bridge-types/bridge-types-suspension.html

 

 


 #4Building Virtual Bridges

 

YouTube plugin error

 Watch the video above. It shows examples of the bridge building program-

 

 

 

 

 

 

Download the game below and construct bridges the train can cross

 

 
Bridge Building Game
Bridge Building Game is a game where you build bridges.
Windows Download (239 KB)
Linux Download (52 KB)
Mac Download (1086 KB)

 

http://www.sciencebuddies.org/science-fair-projects/project_ideas/CE_p007.shtml 

 

Using the Westpoint Bridge design software you are going to build your own bridge and load test the structure.

 

http://bridgecontest.usma.edu/ -this is a free download if you want to practice at home.

 

http://www.newbaybridge.org/classroom/engineeringfor.html

 

Construction Tips

 

  1. Try to keep design simple, using multiples of triangles.  An inverted triangle is more stable than a triangle with the apex on top.

  1. Hot glue tends to cook and melt the ends of the spaghetti, so use just enough to hold pieces together.
  2. The bearing points are the points where the bridge is supported at the ends by the edge of the gorge.  This area should be flat and smooth.  If the bearing point is not flat, the bridge may twist and break.
  3. Spaghetti may be stranded together like a cable or rope.
  4. Spaghetti is brittle and is quite strong in axial tension but very weak in compression.  The hint here is to make the compression members as short as practical, by adding internal web members.

  1. Try to make the spaghetti connections strong but flexible.  If the connections are too rigid, when the bridge starts to deflect, the joints will twist and rotate and put added bending force into the spaghetti.  Spaghetti is not very strong in bending!  In fact, if the ends of the spaghetti are cooked and weakened at the joints, then the bending forces from the joint twisting will break the spaghetti very quickly.
  2. Some people have tried boiling the spaghetti for 25 minutes and then slowly drying it while drawing the spaghetti to a longer and more slender dimension.  The result is a spaghetti member that is very flexible, light in weight yet quite strong in tension.  It is said this process makes for a good tension member but a terrible compression member!

 

 

Tips During Loading

 

  1. Select a maximum of two people from your group to add the load.  Try to predetermine the approximate load your bridge will carry.  The ratio of maximum load divided by bridge weight is important.  The record holding bridge from Camosun College’s Civil Engineering Technology program held almost 90 times its own weight!  This bridge used hollow tubes constructed of spaghetti for the compression members.  The following tables show the current records for each division:
Division Record Load Ratio
Up to and including grade 10
26.6
Grades 11 and 12
40.6
Technology students
86.3
Professional
97.4
  1. Apply the load gently, in suitable increments that are not too big, yet not too small either – it’s nerve wracking!  Use the heaviest weight increments first.
  2. Try not to unload then reload, this causes joints that have rotated to re-adjust and often the bridge fails sooner than expected.
  3. Keep hand and feet out of the way of falling bridge and weights.  Some bridges collapse slowly, while others disintegrate without much warning (but high drama).  

 

 

Smart Bridges  

Smart Bridges

In this video segment adapted from NOVA scienceNOW, learn about engineering innovations that could help detect a bridge's structural weaknesses before they become dangerous.


 

 Google Sketch Up

 

We will now use Google Sketch up to design our own Bridges

 

Working with SketchUp is really easy. Let's practice using a few of the tutorials!

 

 

  1. Quick Start: Video 1
  2. Quick Start: Video 2
  3. Quick Start: Video 3
  4. 3D Warehouse
  5. Textures: An Introduction
  6. Textures: The Basics
  7. Textures: Using Photos 

 


Building the Bridge Models

 

Can you believe it? This bridge was made out of spaghetti noodles!!!!!

 

Here's the fun part- Now you get to build a model based on your design. YOu may use any materials you can think of.

 

Structures: Build It
  The links above take you to:  http://pbskids.org/zoom/activities/sci/#engineering

 

 

Putting it together in a Movie

 

Using Win Movie maker include the following in your movie

 

1. Screen shots of your google design

2. Pictures of real bridges of the same type

3. Screen shots of the Bridge building Game.

4. Pictures of the place on google earth where you would locate your bridge

5. Pictures showing you actual model

6. Video clips of your interview

 

 

 

 

 Hurrah's- The bridges were awesome!!  You all did a great job!

 

 

 

 

 

 

Click here to go back to the Interactive Lesson Page

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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