Since there’s an air gap between that horizontal steel square under the wood 5x5 and the crushed concrete (from whatever cause), it follows that the entire weight was resting on the bottom of the longer metal straps that appear to be connected as one U-shaped piece running through the lower part of the site-fabricated concrete.
Because the steel buckled so badly it could not have been designed by an engineer factoring in a simple redundancy factor to support the entire load on those straps, leaving the whole elaborate thing dependent on the indeterminate crushing strength of that site-fabricated block in an application the builder’s people had probably never seen before. In any case, it looks like a relatively easy fix as far as structural issues go. I hope the person who posted this will provide an update when he finds out what the story is.