Claims that “a city housing 15,000 U.S. troops suddenly collapsed” are false and not supported by any credible reports. Reality check:

Claims that “a city housing 15,000 U.S. troops suddenly collapsed” are false and not supported by any credible reports.
Reality check:

There is no confirmation from the United States Department of Defense or international media of any city collapsing

Military bases may host thousands of personnel, but they are not “cities that suddenly collapse”

An event of that scale would be a major global disaster, instantly reported worldwide

What this likely is:

Clickbait or misinformation

Possibly from simulation videos (e.g., Arma 3)

Exaggerated or fictional storytelling

Bottom line:
This claim is fabricated and unrealistic, not real breaking news.