Something to think about

It would have to be a pretty doggone rigid bridge to stand up to the forces of gravity pulling the edges in towards the center of the earth, which goes against good bridge design. You want bridges to be flexible, not rigid, so that they can expand and contract with temperature, move when forces of wind and nature act on it, and of course allow loads to be carried on them. Because of this, I think such a bridge would collapse immediately. Interesting concept though, if you could create the scenario in a vacuum, somehow find a material rigid enough to withstand gravity, and eliminate all outside forces other than gravity, and execute the support removal instantaneously to get a clean break everywhere, then yes I suppose it might float in theory. Or, if you could make the bridge tall enough that it actually gets into space and is set in a place of orbit, then you could disconnect it and it would "float", or rather orbit...but why would we ever do that now?

Wow

It would collapse under itself.

If it was made of a really strong material if not it would collapse like a wooden wall with termites

In reality, if you're using modern supplies, the bridge would've probably sunk to the ground and destroyed all the ocean towns. Most likely, the bridge would've crumpled in the force of gravity and would've sunken to the ground. Since, it would be put around the world, it would be made of a strong material, but if you destroy the supports it would be like the titanic. It would fall and collapse and sink because of the heavy dense material. But, there could be a chance that before, it sinks it would probably just float for like a millisecond or 2 nano seconds, if it did, it wouldn't be for so long.

No, since:
1. Gravity is not of the same intensity at all parts of the globe (although the differences between those intensities are miniature)
2. Gravities of other bodies (namely the Moon) can easily disrupt the bridge
3. There is no way to remove the supports without having the bridge collapse. Pulling out the supports Jenga-style is obviously out of the picture and explosives are unpredictable and can in of themselves damage the bridge.
4. Even if such a bridge came into existence, it would be highly unstable, as even the objects of the smallest weights or even bad weather (heavy rain, thunderstorm, stong winds etc) can disupt the already fragile balance between the bridge and the gravitational forces of the Earth.