Tacoma Narrows Bridge Design

Introduction

You are to go and study the designs of various bridges and determine the strengths and weaknesses of each.  Once you have a basic understanding of bridge design, you will go to West Point's web site, download their bridge design software and design your own bridge.  You want to design a cost efficient, stable bridge that meets the specified requirements.  After your team is confident that your design meets all the requirements, you will submit your design to West Point's web site for evaluation.  Whichever team design meets the specifications and costs the least will be awarded the contract to design the new Tacoma Narrows Bridge.

1. Go to this bridge research site and explore the various types of bridges.  What design is the most cost effective and structurally sound for your project (crossing over a river)?  Pay close attention to words in BOLD on this page - you will need to understand these terms in order to successfully build a bridge.  Complete this word document by defining the terms on the page, then print it to use as a reference when you are designing your bridge.  (you may copy and paste definitions directly from the web site to the word document).  Print an additional copy to turn in to instructor.
2. After your research, go to the West Point Bridge Design Contest web site and download the bridge design software.
3. Open the software and create a new bridge design.
4. Carefully read all information given on the web site.  The more you understand about the task BEFORE you begin the design, the better.
5. After designing your bridge, run a test to see what needs to be modified.  In order to design a cost effective, stable bridge you will have to test and modify your bridge several times.  Notice that the members change color as the truck drives over the bridge - how do these color changes relate to the load (forces) on the bridge?
6. After running a test on your bridge, click on the calculator button at the top of the page.  This Cost Calculations report will be used to grade your project.  
   
7. Select the chart button (Load Test report) next to the status symbol.  Notice the columns labeled "Compr. force", "Compr. strength", "Tension force" and "Tension strength."  The strength number is the maximum force the member can withstand.  The force number is the maximum force the member experiences as the truck drives over the bridge. To maximize your design, the force number should be as close as possible to the strength number WITHOUT exceeding it. What would happen if the force is greater than the strength of a member? 
8. Once you are satisfied with your design, print the Cost Calculations report, the Load Test report, and the Design report. - these will be used along with your Bridge Research document to grade your design. Notice that the cost calculations report and the load test results report show the Design Iteration # on the page.  This is the number of times you have modified your design after testing and evaluating the results.  This number will be taken into consideration when grading your bridge design.  Usually, the more modifications you make to your design, the better (more cost effective, stronger) it will be.

	Beginning 1	Developing 2	Accomplished 3	Exemplary 4	Score
Cost calculations report	Cost of bridge design is high, little or no iterations (changes) made to design	Cost of bridge design is moderately high, few iterations (changes) made to design, 1 or 2 different materials were used in design	Cost of bridge design is fair/reasonable, several iterations (changes) made to design, 2 or 3 different materials were used in design	Cost of bridge design is extremely reasonable, multiple iterations (changes) made to design, 3 or more materials were used in design
Load test report	Large gaps between strength vs. force values on most members, little or no iterations (changes) made to design	Large gaps between strength vs. force values on several members, few iterations (changes) made to design	Small gaps between strength vs. force values on several members, several iterations (changes) made to design	Small gaps between strength vs. force values on most members, multiple iterations (changes) made to design
Design report	Design is not symmetric, members are randomly placed throughout	Most of design is symmetric, some members are randomly placed on bridge	Design is symmetric with no randomly placed members	Design is symmetric with no randomly placed members. Design is also creative and unique
Bridge Research (definitions - word document)	No definitions completed	Some definitions completed	All definitions completed	All definitions complete with some additional words defined

After you have completed your design, you will turn in 4 reports to the instructor - the bridge definitions (word document), cost calculations report, load test report, and the bridge design report.  You will then submit your design to the West Point web site contest for evaluation.  Remember, you may continue to modify and resubmit your bridge design after you have completed this assignment.  Go to these links for West Point's contest rules and PRIZES for contest finalists.