Physics!

Thanks to the presentation in class, and seeing the different force vectors applied to each part of the trusses, we saw the part the had the most tension was the bar running up the middle of the trusses. And since that, or the bottom middle beam, were the parts the broke for everybody's bridges, it proves the physics. To fix this, we would just reinforce the middle with stronger glue connections, and also make sure that bottom tube piece is folded stiffly, and securely.