Ontario Cancer Institute / Princess Margaret Hospital
Toronto, Ontario

The OCI/PMH structure was developed as a unique response to the needs of the Patient Treatment and Research departments whic hare now housed at the Princess Margaret Hospital.

A critical lack of space on the downtown site required a number of architectural and, hence, structural initiatives to create an integrated solution. The needs of the facility could only be accommodated by an extensive cantilevered section of the hospital 6 m (20 ft) over Murray Street. Special municipal approvals and an innovative structural solution were required for the extremely long cantilevers. Quinn Dressel Associates designed an integrated structural steel/post tensioned deflection control system to maintain the neds of the cantilevers at an acceptable level and to minimize relative floor to floor deflections.

With 13 radiation treatment rooms in the basement area, the wall thicknesses had to be smaller than normal, and this was achieved without compromise to the shielding capabilities, by utilising a special Quinn Dressel high density concrete mix design.

The double height atrium space - framed in structural steel - is an architectural design feature of the building and contains a number of cantilevered interstitial stairs and a suspended elevator machine room.

Co-ordination of the mechanical and electrical services within the building's ceiling spaces was a major undertaking. Special provisions were made on a floor-by-floor basis to handle the various requirements of the mechanical systems specifically.