Yeah this is super fun to watch. I'm guessing they're still doing a big rebar & concrete mat pour that will encase the prefab steel and then they can start cruising on the core. Anyone have any idea if this is true? It will be interesting to see how far ahead the core gets, assuming the below-grade conditions are all reinforced concrete.Look at the composite steel frame core that started yesterday, and completed today. That would have taken 10 days with concrete and rebar. WOW!