Which Bridge Structure Will Hold The Most Weight?

Safety Note: Science experiments should only be performed with a parent's permission and supervision.

Which Bridge Structure Will Hold The Most Weight?
Project Summary
We wanted to find out what bridge structure was the strongest. First I researched bridges, then I came up with bridge designs. I made a hypothesis. At first I thought that the triangle bridge would be the strongest. After I built them I changed my mind. My new hypothesis, was that the curved bridge would be the strongest, the triangle bridge would be the second strongest, the box bridge would be the third strongest and that the bridge that kind of looks like a ladder, would be the weakest. And guess what? I was correct!
My dad is an architect, and he had the idea of the curved bridge.