I was thinking would it be possible to code a bridge game using Unity’s joints? Kinda like the game Cargo Bridge on kongregate where you place the road and the supports trying to make a bridge strong enough to hold up objects.
You could allow the joints 30 degrees up or down for flexing but if they get too much force they break which is already in unity’s joints.
So… would this be possible and realistic? 
This is certainly possible but you should remember that joints do have a processing overhead and so you might get problems if you use too many joints (the number will depend on the target hardware, desktop, iPhone, etc).
I never understood joints, not that I’ve spent a lot of time trying, but looks quite complex. I’d rather code my own workaround for joints!
Joints also have an issue with tension. Search for “Jake’s Rope Script” . There’s lots of info on this there including a video / demo of a rope bridge he built using joints.
I never was a lot into these bridge building games but i was impressed by the Havok and PhsyX bridge destruction demos.
Does there exist a rob this bank train game by blowing up bridges and compareable objects and other situations to get money transports stopped and gold mines cleaned? Best in somekind of a western world with a self ironic touch.
Hmm… Would say 100 joints be laggy?
is that same what you asked http://www.physicsgames.net/ because i play here very easy games please check