How did st. missouri bridge collapse?

St.Missouri bridge collapsed all by the material it was made from and due to the constant amount of rain cold and warmth.

Faulty Design Led to Minnesota Bridge Collapse, Inquiry Finds. WASHINGTON — Investigators said Monday that the Interstate 35W bridge in Minneapolis, which collapsed into the Mississippi River on Aug. 1, killing 13, came down because of a flaw in its design

(Brainliest please)

That really sucks, but i don't know who your leader is, and i don't want to write that much