is is a four-story addition over two existing six-story buildings. The existing structure was already at the limit of its capacity, if not slightly over. In order to add the new structure, four “supercolumns” were threaded though the existing buildings while they remained occupied and fully functional. The addition contains state-of-the-art facilities including 21 new operating rooms, pathology floor, pediatrics floors and a mechanical floor. This is a working hospital and research center with the existing surgical suites on the second “clean” floor that could not be disturbed by construction and the ensuing debris. Due to the inherently disruptive nature of the process of structural reinforcing, it was deemed unacceptable to attempt to reinforce the existing structure to allow additional space to be supported in this manner. It is for this reason that it was decided to design a structurally divorced addition to the existing buildings. During construction, only minimal disruption of the areas surrounding the insertion of the supercolumns occurred. Each supercolumn extends through six existing stories down to a foundation on rock. Above the existing buildings, 160-foot-long trusses measuring 18 feet deep connect the towers. The trusses and supercolumn towers not only support the gravity loads of the addition, but also serve to laterally support the structure for seismic and wind conditions.