So you've finished researching either a local bridge or a bridge using the internet? Great! You're ready to begin creating your three proposed bridge designs!

When a real-life bridge is to be built, a "request for proposals" is announced by the person or group that needs the bridge built.  In this document they will describe the requirements of any design that would be selected, which often include the following: 

You should read about these things if you are not familiar with them.  Do this by clicking on them.

For the purposes of building a model of your chosen bridge, you or your group must design three bridges that will:

• span (cross) a distance of 30 centimeters;
• the deck of the bridge must be at least 5 centimeters above the surface being crossed;
• the deck must allow a golf ball to be rolled from end of the bridge to the other without falling off to simulate the bridge being used by the local users of your bridge; and
• be easy to assemble. 

Engineers and architects will read this document and then create a design proposal that they hope will persuade the group that is needing the bridge built to select them to create the final product.  Usually at least three different design proposals are submitted from different groups for each request.  You will be simulating this by creating three different design proposals that will meet the requirements of the bridge you researched.

To help you with this a "design log" has been created for you.  Open it here and print it out to help you accomplish this task.

Once you or your group has generated at least three different designs, you are ready to select and support the best choice.  Do that now.  Make sure you are able to support why you chose one design over another!  Armed with your winning design,  you're ready to move into the exciting part of this project: construction!