What is interesting is how the collapsed construction looks like the bridge material disintegrated and has not reinforcement.
I wonder what union(s) were involved in the construction of it were and the quality of the cement i.e. how much water did they add to stretch the cement. My uncle (who was in construction mentioned a test called a ‘slump’ test that showed how much or how little water was used in the mix; the concrete was poured into a cone 12” high upside down with the mix, then put a board over end it and turn it over. When you remove the cone you measure how much slump the concrete mix fell. I forgot the number of inches is a good mix but not enough water and it’d hardly slump, too much and it’d drop a lot.