Award of Excellence Residence for the Sisters of St. Joseph

Situated along the edge of the Don Valley at the corner of Broadview and O’Connor Avenues, this four-storey S-shaped residential care facility is the new home for the Sisters of St. Joseph of Toronto. The 96,000-sq.ft. building in the heart of the city is situated on an assemblage of lots adjacent to the heritage-designated 19th century Taylor House. The facility comprises 58 residential suites, a lobby, activity space, chapel, and five private hospital units.

The Sisters of St. Joseph of Toronto wished for a new, smaller and greener urban home to decrease their operating costs and better suit their aging population. They wanted the new residence to foster their health and welfare and collective beliefs, and they wanted it to be closer to their ministries and outreach programs.

The vision of the architect, Shim-Sutcliffe, was to design an iconic building with an emphasis on environmental sustainability and communal living. The relationship between nature and city is expressed in both the exterior and interior spaces of the building.

A single loaded corridor forms the spine of the building, and a series of operable windows line one edge of the corridor. They admit an abundance of natural light and natural ventilation through the corridor and into the suites.

Blackwell, structural engineers, designed the supporting structural system for the unique building form and configuration.

Long span thin

structural systems

The form and configuration presented conditions for various innovative long span thin structural systems. One such system is the substantial reverse terrace along the western face, where sections of the building overhang the last supporting columns by 10 metres.

Paramount to the architectural design was an open floor plan for natural daylighting and community interaction. The sustainable design goals of the project also required large mechanical ducting immediately below the floor slabs. These two requirements eliminated more traditional reinforced concrete overhanging support systems for a flat slab structure, such as post-tensioned concrete beams, deep wall beams, or thick post-tensioned slabs. Steel systems would have been similarly constrained.

The challenge was met with an innovative stepped wall system. At four locations along the mid-section of the building, the walls are stepped progressively farther south at each storey. Each wall is supported at its east corner only, resulting in a tendency of the entire system to overturn. The overturning is constrained by a connection to the floor and roof slab diaphragms at the top and bottom of each wall. The resulting in-plane slab forces are transferred to stiff but distant elevator core walls.

Length and geometry of floor and roof slabs

The length and geometry of the floor and roof slabs, and the relatively large in-plane forces that were generated, required further consideration. Axial creep and steel elongation were included in the deflection analysis, since the diaphragm length had a pronounced effect on overhang vertical deflections.

A semi-graphical modified strut-and-tie method was used to determine the required strength of concrete and reinforcing steel sizes and layouts, due to the non-orthogonal geometry and numerous openings adjacent to the supporting core walls at each end. Higher strength concrete (45 MPa) was used to limit diaphragm deflections and provide adequate strength in these sensitive end regions. Additional reinforcing was also added.

Built to strict sustainability guidelines, the new residence achieves operational savings as well as long-term lifecycle savings. In this project, sustainability extends beyond the physical requirements of creating a green building and includes the longer-term evolution of the Sisters’ organization and its ability to thrive.

Project name: Residence for the Sisters of St. Joseph of Toronto

Award-winning firm (structural engineers): Blackwell, Toronto (David Bowick, P.Eng., Pierre Koch, P.Eng., Anthony Spick, P.Eng., Michael Robbins, Shannon Hilchie, P.Eng., Zerry Zhang, P.Eng., Eric Chung, P.Eng., Belinda Wong, P.Eng., Greg Saka, P.Eng., Grazyna Czarnecka, Dorothy Pawluk)

Client: Shim-Sutcliffe Architects

Other key players: Crossey Engineering (mechanical & electrical); R.A. Heintage (building envelope); ERA (heritage); Dr. Ted Kesik (sustainability); Nak (landscape); David Hine (code); Eastern (construction).