Q: (Initially posted January 19, 2005) FROM STUDENT MEMBER BRITTANY C. IN NJ
In my Women in Engineering Class we are building bridges. I was curious whether a substructure generally increases strength along with a superstructure, or just one or the other would be better for strength. Thank you.

A: FROM MENTOR SARAH SHIRK IN IL
Hi Brittany- The substructure can support longer and stronger bridges. See http://www.betterroads.com/articles/brfeb01b.htm for more information. Of course superstructure is also vital. See samples at http://endimus.com/oldcontent/files/projects_en.htm

There are many calculations that go into each design. So I do believe your questions is best answered when the specifics are available such as length of bridge, height of bridge, and of course expected load.