There was a median underneath, why didn’t they
at least have temporary supports underneath?
It was only half the bridge at that point.
My GUESS is liability issues if a vehicle were to strike it, possibly dropping the entire span.
Also, a temp support would require a long traffic blockage.
A serious foundation to support the weight would be required below grade.
They were likely aware of the thin safety margin, but confident in the construction plan.
Time will tell.