The exterior treatment, consisting of a combination of brick facing and exposed sand-blasted concrete, presented interesting design opportunities. The design expression introduces two colours of brick with banding and patterning, along with sand-blasted concrete base and window surrounds that provide visual interest and scale appropriate to an elementary school.
Dave Mungall, Architect
Pye & Richards Architects Inc.
Speed of construction and budget limitations were the two key project criteria for this client. The project established by the client Conseil des Écoles Publique de l'Est de l'Ontario was to construct a new 500 pupil space elementary school in Ottawa, within extreme time constraints. From the time of land purchase, only 6 months were available to construct the new school, in order to meet a school opening in September 1999. SiteCast Construction approached the school board with a commitment to undertake this task using their tilt-up construction method. The school design was based on that of a previous school designed for this Board, and modified to suit the technical requirements of tilt-up concrete construction. Other design modifications were introduced at the request of the Board to respond to staff and parent comments derived from the original school.
What Is Tilt-Up Construction
The term “tilt-up” describes a method of constructing concrete walls rapidly and economically. Wall panels are cast horizontally on the floor slab. After they have attained sufficient strength, a mobile crane lifts the panels up and sets them on a foundation. The erected panels are temporarily braced while the roof and upper floor framing is constructed.
Tilt-up concrete is most commonly used for one to three story buildings, but its use in multi-story low-rise office and warehouse buildings is growing. This process offers architects almost unlimited freedom to arrange and assemble panels, plus a wide choice of surface finishes. Techniques continue to evolve with new research and innovations, furthering the advantages of tilt-up construction.
Benefits and Outcomes
Quick Response to Tight Schedule
With tilt-up, construction can get started right away, avoiding the delay associated with manufacturing schedules. Earlier startup means better cash flow for owners and developers, as well as earlier project completion and owner occupancy. It could also mean getting a jump on the summer construction season or getting a foundation in during the late fall before the winter frost.
Speed of Construction
This project benefited from an estimated 40% reduction in construction time when compared to an identical (slightly smaller) school built at the same time. The Cumberland Elementary School was built using tilt-up construction in 5.5 months whereas its identical twin took 9.5 months to complete. For school boards that need quick reaction to changing student demographics, this could mean waiting a full budget year for a school to be built the conventional way. With tilt-up construction, new schools can be built relatively quickly to meet new population demands.
On-Site Flexibility and Quality Control
The design specified a brick veneer to offer a durable exterior finish and aesthetic appeal. The brick faces are less expensive to install with tilt-up as they are cast into the concrete panels. This method is faster and more cost-effective. On this project, it resulted in a cost-savings in labour required for installation by 9%. In addition, the reduction in trades involved in the construction of the building envelope minimizes delays and provides consistency in quality of the finished product.
Lower Capital Investment
Faster construction means reduced carrying costs during construction. It facilitates a more timely pay back of financing charges and faster revenue generation for the developer/owner.
A concrete structure can take whatever is thrown at it. Whether it is internal wear and tear or severe weather conditions on the exterior. In either case, less time and money is required to maintain a concrete structure.
The insulated concrete-insulation-concrete “sandwich” panels that make up the exterior wall panels provide an superior thermal rating. The result is substantially lower heating and cooling energy costs. In fact, recent energy audits, conducted by SiteCast, produced savings of 48% in the school’s gas consumption, when compared to the conventional school.
Source: ACI Award Submission
|Owner||Conseil des Écoles Publiques de l'Est de l'Ontario|
|Architect||Pye & Richards Architects|
|Engineer||Limit Design Management|
|Contractor||SiteCast Construction Corporation|
|Concrete Supplier||Essroc Italcementi Grou|