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AlvinofDiaspar
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And on the glass staircase, from the same:
THE OPENING
Shattered glass staircase shatters nerves
Four Seasons steps may be the most complex feat of glass engineering ever. And it almost wasn't ready in time
SANDRA MARTIN AND VAL ROSS
Exaggerate the scale by a thousandfold -- otherwise, the frenzied tidying and last-minute daubing at the Four Seasons Centre for the Performing Arts this week were the same rituals ordinary folk perform before a housewarming. On Wednesday afternoon, four senior architects from the firm Diamond + Schmitt Architects were checking lights, monitoring finishes and examining seals on doors as the Canadian Opera Company prepared for its ribbon-cutting ceremony tomorrow . Jack Diamond, having inadvertently stepped into some caulking on the bottom step of the glass staircase, was down on his hands and knees polishing the maple floor to erase his solitary imprint.
But why was the caulking still sticky just days before the opening?
And why won't the lighting under each glass step be ready either for the ribbon-cutting or next Tuesday's gala concert?
The answer lies in the complex design of the glass staircase -- and a discovery that some found unnerving just a few weeks ago.
The staircase, which vaults 14 metres from the first floor to the second, and then another 14 metres, may be the most complex piece of glass engineering in the world, says Diamond -- probably the longest unsupported glass staircase ever built. John Kooymans, senior associate at Halcrow Yolles structural engineers, one of the companies that has turned Diamond's opera-house vision into Four Seasons reality, explains that instead of being supported, the stairs are hung from the ceiling by steel rods.
"All the critical joints are moveable, to allow for differential movements between the main structure and the glass structure," says Kooymans. And movement can be affected by everything from the number of hefty opera patrons who decide to descend at any one time, to snow-loading on the Four Seasons's roof.
The stair is built of heat-tempered, low-iron, extra-strong glass. Nevertheless, it had its breaking point, as was discovered during installation back in late March, when four of the 23 panes of glass shattered. The workers had to take those parts of the stairs down and try to identify the problem. After eliminating design and engineering faults, they realized that tolerances of some of the materials were not to spec. Steel is relatively flexible, glass relatively brittle: The differences were out by just two to three millimetres in the case of the glass, says Kooymans, but enough to cause the higher stresses.
So new staircase materials were reordered from the German manufacturer, Josef Gartner of Munich, and shipped to Canada. By May 15, the Four Seasons Centre workers and Yolles engineers assembled for the in situ test. Some held their breaths as more than 9,000 kilograms of steel counterweights were hung off the bottom of the stair (the equivalent of 100 opera patrons weighing 200 pounds each standing simultaneously on the structure).
"The stair passed with flying colours," says Kooymans. Well, not all of it: The lighting fixtures will be installed "in the near future," but no date has yet been set. (Diamond suspects that the manufacturer had used an old set of drawings.) "It was nerve-wracking," says Diamond. "A close-run thing."
Kooymans points out that there were also breakages during installation of the glass on the exterior of the building. Such occurrences are not uncommon.
But the staircase was special. Says Kooymans, "No one has ever done this before. It looks simple and elegant, but there were erection issues." The main thing is, the structure is ready to bear human traffic.
AoD
THE OPENING
Shattered glass staircase shatters nerves
Four Seasons steps may be the most complex feat of glass engineering ever. And it almost wasn't ready in time
SANDRA MARTIN AND VAL ROSS
Exaggerate the scale by a thousandfold -- otherwise, the frenzied tidying and last-minute daubing at the Four Seasons Centre for the Performing Arts this week were the same rituals ordinary folk perform before a housewarming. On Wednesday afternoon, four senior architects from the firm Diamond + Schmitt Architects were checking lights, monitoring finishes and examining seals on doors as the Canadian Opera Company prepared for its ribbon-cutting ceremony tomorrow . Jack Diamond, having inadvertently stepped into some caulking on the bottom step of the glass staircase, was down on his hands and knees polishing the maple floor to erase his solitary imprint.
But why was the caulking still sticky just days before the opening?
And why won't the lighting under each glass step be ready either for the ribbon-cutting or next Tuesday's gala concert?
The answer lies in the complex design of the glass staircase -- and a discovery that some found unnerving just a few weeks ago.
The staircase, which vaults 14 metres from the first floor to the second, and then another 14 metres, may be the most complex piece of glass engineering in the world, says Diamond -- probably the longest unsupported glass staircase ever built. John Kooymans, senior associate at Halcrow Yolles structural engineers, one of the companies that has turned Diamond's opera-house vision into Four Seasons reality, explains that instead of being supported, the stairs are hung from the ceiling by steel rods.
"All the critical joints are moveable, to allow for differential movements between the main structure and the glass structure," says Kooymans. And movement can be affected by everything from the number of hefty opera patrons who decide to descend at any one time, to snow-loading on the Four Seasons's roof.
The stair is built of heat-tempered, low-iron, extra-strong glass. Nevertheless, it had its breaking point, as was discovered during installation back in late March, when four of the 23 panes of glass shattered. The workers had to take those parts of the stairs down and try to identify the problem. After eliminating design and engineering faults, they realized that tolerances of some of the materials were not to spec. Steel is relatively flexible, glass relatively brittle: The differences were out by just two to three millimetres in the case of the glass, says Kooymans, but enough to cause the higher stresses.
So new staircase materials were reordered from the German manufacturer, Josef Gartner of Munich, and shipped to Canada. By May 15, the Four Seasons Centre workers and Yolles engineers assembled for the in situ test. Some held their breaths as more than 9,000 kilograms of steel counterweights were hung off the bottom of the stair (the equivalent of 100 opera patrons weighing 200 pounds each standing simultaneously on the structure).
"The stair passed with flying colours," says Kooymans. Well, not all of it: The lighting fixtures will be installed "in the near future," but no date has yet been set. (Diamond suspects that the manufacturer had used an old set of drawings.) "It was nerve-wracking," says Diamond. "A close-run thing."
Kooymans points out that there were also breakages during installation of the glass on the exterior of the building. Such occurrences are not uncommon.
But the staircase was special. Says Kooymans, "No one has ever done this before. It looks simple and elegant, but there were erection issues." The main thing is, the structure is ready to bear human traffic.
AoD