What do you do?
Decide how much it bothers you.
If it's a minor nuisance, talk to them and see if things improve. If they do, great; if not, it's minor enough to ignore.
If it's a dealbreaker, talk to them and see if things improve. If they do, great. If not, decide what kind of hassle you want - if you feel like taking this head-on, start filing complaints with the landlord and get a noise-meter, start logging incidents & decibel levels in a diary, contact whatever the USA equivalent of you local area's environmental noise service, and generally make a major nuisance of yourself to everyone else and see if anything changes. At some point, they'll either reduce the noise or things will escalate to a point where you find the opportunity cost of doing all this in terms of your time (and potentially money) becomes too much to sustain.
At that point (or if you just don't want this sort of hassle at all), you'll have to decide to put up with it or move. Preferably to a top-floor apartment or a house, to reduce the chances of recurrence.