
Cool concept for a world. Although wouldn’t a design where all three bridges intersected in the center make more sense? It would allow for a hub of international trade that was connected directly to all three countries while remaining a separate entity. You might already have a reason why not, but I’m just curious.
The bridge was build by Pycern (imperial empire) to encourage trade between the 3 cities. The bridges are large and wide enough that they each have their own small cities in the middle point of the bridge. The reason why it’s better than boats is because boats are generally either owners by the wealthy, or cost a lot of money to be a passenger on. With the bridges, it encourages migration and trade for everyone, regardless of economic status.
As far as the plate techtonics go, the reason why the shatterlands looks like that is because there is a primordial “ooze” thing that emerged from the earth about 50 years ago, making Venarion a dead city and breaking apart the land when it emerged. It’s been dormant since the destruction of the city, but people still watch it just to be sure (The Rehabilitation and The Guardians). If you couldn’t tell, that part of the world is obviously inspired by A song of ice and fire.