It's an incredibly common urban legend even in the city itself - fortunately with no basis in reality.
As an example the Metropolitan Life North Building right next to Madison Square Park was originally designed in the 20s to beat the Empire State for height (but sadly, the Depression happened), and that plot of land is firmly on the "soft" ground "unsuitable" for tall skyscrapers.
Not only do we not need the bedrock now, it appears we never needed it - and the engineers of the early 20th century knew this as well as we do.
Yes. And any tall building in SF's Embarcadero stands in defiance of the need for bedrock. A lot of the land there is just old, accidental landfill.
Also, I think, but, I'm not sure, that they built this extremely large, heavy structure right over the bay itself a few years back, something about helping cars get from Oakland to SF and back. I don't know how much bedrock they found underneath the supports for that thing, whatever it's called. Can't seem to remember its name ...
As an example the Metropolitan Life North Building right next to Madison Square Park was originally designed in the 20s to beat the Empire State for height (but sadly, the Depression happened), and that plot of land is firmly on the "soft" ground "unsuitable" for tall skyscrapers.
Not only do we not need the bedrock now, it appears we never needed it - and the engineers of the early 20th century knew this as well as we do.