basics of bridge construction
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TRANSCRIPT
Basics of Bridge Construction
Build a Spaghetti Bridge Project
Photo Journal
Created By
**** ******
April 2008
Planning
• 8 Processes of Engineering
• Identify the Problem This problem was given Build a bridge out of Spaghetti.
Span between 20 and 30 inches Wide enough to allow a 2 x 4 flat to pass unimpeded through all supports. Able to support 15 lbs at any point along deck• Research the Problem What makes a bridge strong
• Develop Possible Solutions
• Select Best Solution
• Construct a Prototype
• Test and Evaluate
• Redesign
• Communicate Solution
The Challenge
Challenge Research , design, build and
revise:• A bridge using only spaghetti
and hot glue• Bridge span should be
approximate 20 -30 inches• Bridge base must be smooth
enough for 2x4 to pass through unimpeded
• Bridge should support 15 lbs at any point on deck
Step 1 Research
Interactive lessons from PBS Building Big 1st Bridge Basics exerciseathttp://www.pbs.org/wgbh/buildingbig/bridge/basics.html
2nd The Bridge challenge http://www.pbs.org/wgbh/buildingbig/bridge/challenge/index.html
3rd Forces Lab Exercisehttp://www.pbs.org/wgbh/buildingbig/lab/forces.html
Watch History Channel/National Geographic True Story of the Bridge of River Kwai
Step 2 Design Bridge
• Choice Warren Truss bridge
• Looked Sturdy and seemed to be able to be built with Spaghetti and hot glue
• Need to calculate the length of the span, height of trusses, width of roadbed
• Decide on how many pieces of spaghetti would be used in one bridge section
Step 3 Begin Construction
Prototype 1
• Follow design and construct first truss
• Double check that all sections are right length and same number of spaghetti in each
• Place sections in triangles and begin gluing in proper places
• Do not use excessive amounts of glue
Prototype ConstructionThe trusses
Prototype 1
• Construct 1st truss
Prototype ConstructionThe trusses
Prototype 1
• Construct 2nd truss
Prototype ConstructionStep 4 begin construction of base
Prototype 1
• Measure lengths and count number of spaghetti pieces in each section
• Place longer sections on bottom and shorter sections on the top
• Glue and let sit to dry
Prototype Construction Step 5 Finish construction
• After all the different pieces of the bridge have finished drying its time to finish the prototype
• First you must place a road bed on the base
• Put the trusses on the base and glue and let set
• Then place the cross braces at the top of the trusses for a bit more support
• Let set for awhile
Step 5 Finish Construction
Completed Prototype
End view
Prototype ConstructionStep 5 Finish Construction
Completed Prototype
Side view
Step 6 Test Prototype for problems
After the glue has set, check the bridge for potential problems
• The trusses were not all the same height
• The base was not strong enough
• There was a noticeable curve
Step 7 Redesign Bridge
• When redesigning the bridge make sure that all the problems with the Prototype were fixed
• Decide if change needs to be made in order of construction
Final Product Construction
Step 8 Measure and Cut
Correcting my first error, not every piece of spaghetti is the same length
Correction
• Measure each piece of Spaghetti and cut to proper lengths
Final Product ConstructionStep 9 Trusses
• Correcting 2nd error; not all triangles were the same size
• When constructing the trusses measure out the points for all the triangles to meet the beams.
• Glue and let set
Final Product ConstructionStep 10 Base
Correcting 3rd error
Base was curved and did not lay flat
The glue on each piece must set and then be trimmed to allow bridge deck to be flat and level
Final Product ConstructionStep 11 2nd layer added to base
The bridge must hold 15 lbs at any point on the deck.
To give the deck added strength a complete layer of spaghetti was added to the base running perpendicular to the beams and future deck.
Final Product ConstructionStep 12 Assemble structure
Project Completion ( almost)
Now all that was left was to trim decking to square.
Project Completion
End View
Project Completion
Side view
Project Completion
Overhead view
Final Testing
Spanning 2 Chairs
Testing Bridge Strength
I borrowed 2 weights
from a local hardware
store
Testing Bridge Strength
10 lbs
No Problem!
Testing Bridge Strength
15 lbs
I did it!
Communication
Presentation of Photo Journal
Created using Microsoft Powerpoint
Piccasa 2 Photo Editor
Thanks to:
PBS: Build Big
Price Of Freedom : True Story of The Bridge on River
Kwai
Unschooler’s Engineering Club
2007 – 2008