Blackwell Structural Engineers Toronto, ON

Project Details

Fabric 1

Précontraint 1302 Formula S
Producer: Ferrari S.A.
Supplier: Ferrari S.A.

Engineer Name 1
Renée MacKay-Lyons

Engineer Company 1

Design Name
David Bowick

Design Company

Architect Name
Patrick Li

Architect Company
EDA Collaborative Inc.

Fabrication Name
Lincoln Gallagher, Derek Penney

Fabrication Company
Soper's, Depco

Subcontractor Name
Jamie Gallagher

Subcontractor Company
Tensile Integrity

Project Manager Name
Rakesh Mistry

Project Manager Company
Town of Oakville

Installation Name
Derek Penney

Installation Company

Please describe the project specifications

The Bronte Park Amphitheater structure is a multipurpose pavilion in Bronte Heritage Waterfront Park in the Town of Oakville, a suburb of Toronto.

The Bronte Heritage Waterfront Park is a popular destination for tourists and locals and features an active marina, conference center, fisherman’s wharf and green space. The amphitheatre will provide an outdoor performance venue as well as shelter from rain and shade for respite and picnics etc. It’s dramatic and iconic form will be highly distinct and recognizable and is expected to make it popular for landscape and wedding photography.

The sailing culture of the marina is a dominant feature of the park and a nautical aesthetic was an objective for the amphitheater structure. Stainless steel marine cables and fittings have been used extensively. The main mast was detailed deliberately to resemble the mast of a sailing ship and the spreader beam intended to invoke a nautical spar.

A stainless steel cable screen provides a backdrop for the stage. The cables are tensioned between a French drain at grade and the troughs above into which rainwater is channeled. This feature manages rain splash in summer and will accrete ice in the winter creating a sparking translucent curtain. It also provides an opportunity to hang banners or support climbing plants.

What was the purpose of this project? What did the client request?

The Bronte Park Amphitheater fulfills a number of functions within the park.

First and most explicitly it is an event space. The fabric provides 1,000 sf of shelter from sun, snow and rain for performances in the park. The superstructure has been designed with a series of 2,000 lb. “pick points” to suspend rented lighting trusses and audio visual equipment. The cable screen provides an opportunity for a backdrop.

The structure is also an iconic and recognizable form that responds to the harbor and marina and will become a symbol for the park and the Oakville Waterfront. It will be a destination for visitors seeking shelter or taking pictures.

What is unique or complex about the project?

This project has incorporated a number of unique and complex elements in fulfilling its function.

Two membranes overlap to form the structure rather than a single covering membrane. The overlap was carefully considered to maximize rain protection while allowing light through to maintain a bright open space and create visual interest.

The spreader beam, which supports the outstretched wings of the membranes, floats in a cable net in a tensegrity fashion, rather than connecting to the mast. This presents challenges both from a structural design and analysis standpoint and to the erector but give the structure a sense of “look ma no hands” magic.

The apparently symmetric structure is asymmetric to allow the membranes to overlap. This along with the floating spar resulted in an extremely complex geometry, both from a detailing and fabrication point of view.

A pair of troughs, fabricated from bent plate, do dual purpose; accumulating rain water from the two membranes and providing the tensioning boundary for the stainless steel screen. The screen itself is unique in its ambition to create ice in the winter and form a glassy curtain.
The foundations are possibly the most unique and complex part of the project. Rather than large discrete concrete footings or grade beams, the foundation is entirely made of galvanized steel. Large beams connect the mast and stays making the structure a “closed” system. The ends of the interconnecting beams are supported on steel sleepers which spread the load onto the native fill material. The use of steel foundation allowed the below grade work to be completed extremely quickly, in just a matter of days, to accommodate an ambitious schedule. It also ensured that base anchors for the mast and stays would be accurately located to minimize site adjustment and rework for the structure. An analysis was undertaken to ensure that the longevity of the buried steel would be consistent with the intended design life of the project.

What were the results of the project?

Within days of the erection of the structure, many weeks before the opening of the project, the Town of Oakville began receiving requests for permits to use the site for wedding photography. As a waterfront icon, the project had already made its mark.

The first major event will be July 1, 2017; Canada Day celebrations for Canada’s sesquicentennial, being called the Canada150 celebration. After a series of day time family concerts the stage will be occupied by tributes to two iconic Canadian bands, the Guess Who and Supertramp. It will also provide context for a spectacular fireworks display.

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