Thanks Pete. I've always been facinated by the different bridges I've seen over the years. Both the designs, and the engineering behind them.
The idea of trusses, and how load is transfered, is something I use, but not every day, in wood framing.
I'm always amazed at the engineering of opening bridges on rivers, whether they are draw bridges, or pivot bridges. The point load on the pivots or hinges is enourmous, and the cable/pulley systems, along with the winches that do the lifting, are just facinating.
Someone posted pictures of a water wheel lock system that was built in Europe, to get boats down from one level to another. It is so cleverly balance that the muscle to move it is minimal. But the loads are enourmous. Clever people, for sure.