Architects Strictland and Symens, 1888, Renaissance Revival.
The building was designed in the style of an early Christian basilica with a clerestory roof. It may have been built as a self-supporting structure and simply placed on top of the building so that any explosion would raise it without destroying the walls (from the COC’s website).

These three self-anchored suspension bridges span the Allegheny River in downtown Pittsburgh. From front to back they are the Roberto Clemente Bridge, the Andy Warhol Bridge and the Rachel Carson Bridge.