> IANAL but I assume that if I purchased a tract of land and built a bridge on it, I could create it as I please, given that I would be liable for damages should the bridge break and harm somebody on my property, not unlike a slip-and-fall.
Depends on where you buy your land, most likely. If you buy in an unincorporated territory, you might get away with whatever if there are no county or state regulations. If you're buying in a city/town/village, you can expect that basically any construction project will be subject to code requirements and permitting. To get permitted in such a situation would typically require an appropriately engineered design with signoff from a civil PE.
Depends on where you buy your land, most likely. If you buy in an unincorporated territory, you might get away with whatever if there are no county or state regulations. If you're buying in a city/town/village, you can expect that basically any construction project will be subject to code requirements and permitting. To get permitted in such a situation would typically require an appropriately engineered design with signoff from a civil PE.