The last two photos tell it!
Last four photos
Was repair delayed because of Chivi lockdown???
Maybe. Probably.
It sure looks like the spalling exposed some rebar, which appears to have corroded. It also looks like there might be insufficient “cover” in some of those locations. Some of the other photos look bad, but are mostly cosmetic.
Looking at the original structural framing plans, it’s all mild steel, no post-tensioning, which would make sense for that era, and it doesn’t “look” to be over-reinforced. In other words, the failure should have begun with plastic deformation of the reinforcing bar, not with a sudden compressive failure of the concrete.
IE, there should have been (and may have been) signs of imminent failure. We won’t find one single point of failure, but a long chain of contributing factors, imho.
Yup. Poured to wet.
I’ll bet the strength cylinder tests were all faked.