Case study: retractable roof keep BC Place Stadium patrons protected
BC Place in Vancouver, BC, Canada, has been transformed into a year-round, open-air facility with an innovative retractable roof featuring SEFAR® Architecture’s TENARA® architectural fabric. The renovated facility is once again an iconic architectural landmark for the province.
Elements of design
The most prominent element of the new stadium roof is the inner, retractable TENARA fabric roof that extends from the center of the stadium where it’s hidden inside of a pod above the video board to a fixed outer roof. The opening is 109 yards by 93 yards, the same size as the field below, and takes about 20 minutes to open or close.
The retractable roof consists of pneumatically stabilized membrane cushions constructed from two layers of TENARA architectural fabric. The cushions are pre-stressed using hydraulic tensioning units and inflated with fan units. The retractable roof is suspended from steel cables spanning between six 164-foot steel masts by specially designed sliding and driving carriages. The deflated cushions are stored until it is time to close the roof and the driving carriages pull the fabric outwards radically towards the perimeter; to close the roof, the process is reversed. In the winter, the retractable roof edge is inflated to seal it along the glass shelf at the inner edge of the permanent roof to form a rigid shape and weather-protective seal.
“SEFAR Architecture’s TENARA fabric’s composition makes it inert—delivering environmental resilience and a long-lasting, high-quality architectural finish,” says David Campbell, president of Geiger Engineers, the engineer of record on the project.
The building as a whole
Revealing more than 89,729 square feet of clear blue sky, the new retractable roof allows BC Place to tailor the atmosphere for any event. In the past, the facility had to turn away events due to the sealed air configuration that prevented natural light transmission and caused heat and humidity issues during the summer. BC Place is now equipped to handle summer festivals and concerts under the sun, football games under the stars, indoor exhibits protected from rain and much more.
The facade is made from 144 transparent ETFE panels that protect the facility’s 55,000 spectators from inclement weather. The outer fixed roof is made out of 36 glass/PTFE panels. The new roof system is also more energy efficient than the previous air-supported roof, saving the facility 25 percent on energy costs.
“TENARA fabric provided the durability, strength and foldability that we needed for this ambitious pneumatic retractable membrane roof,” says Campbell. “In addition, TENARA has the high light transmission we desired for the retractable roof at BC Place. It greatly enhances the roof closed daylighting of the system.”
“We chose to design with TENARA because of its folding capabilities and translucency,” says Christoph Paech, project manager for Schlaich Bergermann & Partners, roof design engineers on the project. “We performed several tests during the design phase, including a folding mock-up, and as a result the engineering of the roof was straightforward and successful.”
Who made BC Place’s recent history come alive?
BC Place originally opened in 1983 and was the world’s largest air-supported dome stadium until it closed in April 2010 for renovation after serving as a venue during the 2010 Olympic Games. The $563 million revitalization project also included a new all-weather turf playing surface, upgrades to the mechanical, electrical, lighting and sound systems, enhanced entrances and concourses, outdoor landscaping and replacement of 50,000 seats.
The BC Place project was completed in September 2011. Members of the project team include architect Stantec, Edmonton, Alberta, Canada; engineer of record Geiger Engineers, New York, New York; engineer Schlaich Bergermann and Partner LP, New York, New York; and engineer Tensys, Bath, U.K.; Hightex GmbH, Rimsting, Germany, was the fabricator and installer for the retractable roof and the outer roof.