Last week Pittsburgh joined the ranks of Chicago, New York, Baltimore and Durham NC with a Request A Rack Program and in most of those cities you can do it via an online form.
Request a rack usually is made available for commercial property owners in business districts, the city buys, sites and installs the racks. Currently no such program exists in Philadelphia, although you can install your own rack by obtaining a permit from the Streets Department Right of Way unit.
Pittsburgh's "Three Rivers" Bike Rack celebrating the Allegheny, Monongahela and Ohio Rivers. What could Philly's signature look like? - Photo Bike Pittsburgh