I can't find the answer with Google, but maybe someone here knows.
During the raising of Chicago, how did they get the jackscrews under the buildings in the first place? Especially those (presumably) positioned in the interiors (as opposed to edges) of the buildings?
But, presumably, you want to put the jacks where the structural walls of the basement already are? Is this not the case, or is the basement dug away piecemeal as jacks are inserted?