General Contractor: Dawson Wallace Construction Ltd.
Reinforcing Bar Fabricator: A & H Steel, Ltd.
Total Project Size: 81,806
Award: 2012 CRSI Award Winner — Educational Facility Category
Photography: Jason Ness Photography (post construction), Ten Speed Design & Development, Inc. (construction)
STRUCTURAL FRAMING SYSTEM
The St. Joseph Seminary chapel is constructed of conventionally reinforced concrete. The concrete moment frame at the chapel’s west end, includes a strut and tie model in order to allow for mechanical openings. The chapel’s walls are reinforced with #15 M at 200 mm on centre each way each face in order to keep cracks to a minimum. Within these walls there are 7 – 6 m x 1.5 m openings. The openings were reinforced to minimize cracking in the corners. This was done by using four 15 M bars each face on the diagonal at each corner. Using small diameter reinforcement allows for the bars to be developed to arrest potential cracks, keeping them to a minimum.
The architect desired the casting of a long horizontal slot along each wall in which the Stations of the Cross are placed. The reinforcing was detailed to allow for the long slot within in the wall while at the same time, reinforcing was coordinated with the electrical consultant to also allow for lighting to be placed within the slot. During construction electrical conduit and steel reinforcing were adjusted to provide the best possible solution.
The chapel’s concrete walls were cast after the grade beams and structural slab were in place. This was done so that the large amount of formwork had a firm foundation. Tie hole locations were kept to a minimum because of strong coordination between the designers, the formwork supplier, and the concrete supplier.
UNIQUE STRUCTURAL AND/OR ARCHITECTURAL DESIGN FEATURES
- Reinforcing was chaired and tied only to the outside face of the wall so that no wire or chairs would be visible on the interior concrete surface.
- The inside face of the formwork was erected first, allowing rebar to be tied in place before “buttoning up” the outside form. During rebar placement, formply on the inside face was protected from accidental damage by full height woven geotextile fabric.
- The design called for square corners to be formed formed (no chamfers).
- Tight skin reinforcing spacing (15M@200 EW EF) to control cracks to sizes not visible to the naked eye.
- Monolithic concrete pour for 11m.
- Coordination between reinforcing and electrical conduit to allow for hidden lighting within the concrete slots.
- Approximately 350 cubic metres of concrete cast without construction joints while achieving the highest possible levels of architectural finish.
- Concrete moment frame to resist lateral loads.
- 6 m high openings in concrete wall to accommodate stained glass windows.
- 150 mm horizontal slot in concrete wall to accept the Stations of the Cross along the side isles.
- Through various mock-ups, “accidental” damage to the form work from reinforcement placement and repair methods were tested.
REASONS FOR CHOOSING REINFORCED CONCRETE
The Archbishop of Edmonton made the influential statement at the outset of the St. Joseph Seminary project, “The Catholic Church thinks in hundreds of years.” That one simple declaration helped shape the entire design, guiding the project team to create a beautiful seminary with a sense of permanence, a modern rendition of traditional church architecture with timeless elegance. Traditional forms of church architecture — arches, buttresses, and side aisles — are reinterpreted with modern materials. At the heart of the seminary, visually and spiritually, is the new chapel, a sanctuary created entirely with cast-in-place fair-faced visually exposed concrete. The concrete gives the space a character, warmth, beauty and permanence that could not possibly be duplicated by any other construction material.
Using white self-consolidating concrete cast in a single massive pour, the chapel walls are 450 m thick and 11 m high. Built with some of the most strict appearance controls imaginable, the interior surface of the concrete is the final visually exposed finish without sandblasting, sack-rubbing or any other cosmetic treatment. The result is a stunning chapel that beautifully portrays the simplicity and elegance of concrete, framing historic French stained glass windows.