CKNW - BC Place stadium roof collapsed

[120dB]

News 1130 is reporting the dome will be re inflated Wednesday! Horayy! I wonder what time as I will so much love to see it!

I fondly remember my Dad and I watching them inflate the dome in 1982. It was a cold Sunday morning, about minus 3 deg, and we were up at City Hall looking across with my binoculars.

I remember insisting to Dad that it wouldn't work; I couldn't understand how air pressure could inflate 300 tons of roof. Later in the day they let the public inside to see it.

I remember yelling inside so I could hear my echo. Dad told me to shutup. Fond memory...

Wednesday let's raise the roof!!!

[Lions_Fan_4_Life]

great, now i can't go see it.

[B.C.FAN]

B.C. Place and the manufacturer have not even completed their damage assessment and have not determined the appropriate course of action on repairs. The first panel that was ordered did not arrive on schedule. It's now believed that a second panel will need replacing. I would not expect the repairs to be made by Wednesday.

Here's the latest information on the B.C. Place website, including some photos and a disagram of the damaged panels.

http://www.bcplace.com/

Click on the red bar to read the update and view the photos and diagram.

[Gerry]

CTV had an architectural expert on who suggested they take the roof off now, and keep it off past the Olympics.

Who is this clown? Does he not know there's no drainage in the place? That the electrical is indoor standard? That much of what BC Place stages is dependent on having an indoor facility? Or that the walls which lean into the facility are supported in part by the upward pressure in the roof's design.

Talk about irresponsible.

I agree that the stadium needs a roof. The entire thing was designed as an indoor facility, but I am curious about the idea that the roof is structurally required. Where did you get this from? I have heard others say the same thing lately.

I can't see that the walls require the roof, or any upward pressure on it, as the walls seem to be doing fine right now without any upward pressure, and there would have been no upward pressure in the first place while the roof was being constructed. The roof adds nothing to the walls, except load. IMO, BC Place would continue to stand just fine without a roof, structurally speaking. The only wild card might be wind load on certain elements within the building should it be exposed to the elements, but I doubt that that would affect the overall structure.

[TheLionKing]

Small consolation but the football turf is not damaged.

[sj-roc]

Does he not know ... that the walls which lean into the facility are supported in part by the upward pressure in the roof's design.

Talk about irresponsible.

I can't see that the walls require the roof, or any upward pressure on it,

I'm not 100% knowledgeable on the architectural engineering behind BC Place, but if I understand Jim's point properly -- and I welcome any correction he has to what I'm about to state -- the positive pressure inside the building, when the roof is inflated, pushes outward on the walls. This is like how all points on the surface of an inflated toy balloon are stretched in different directions, away from its centre. Given enough time, it's not impossible that this could slowly knock the walls over, so you extend the building's lifetime by tilting them inward a bit to compensate for this (i.e., the building isn't cylindrical, even in a rough approximation, but has a slight vertical taper). At the same time, this requires that the roof be inflated since otherwise, those inward leaning walls will conversely be less stable over time.

as the walls seem to be doing fine right now without any upward pressure, and there would have been no upward pressure in the first place while the roof was being constructed.

As I suggested, it's a gradual effect, mitigated by the fact that since 1982/3, the roof has spent far more time inflated than not. If the roof had never been installed with the walls constructed as I described above, BC Place might well have caved in by now, but I don't think it would have happened overnight.

The roof adds nothing to the walls, except load.

It does add a load, which I suppose would complicate the design of the building, but I think the positive pressure exerted on the inner walls would also be a consideration.

[Gerry]

Does he not know ... that the walls which lean into the facility are supported in part by the upward pressure in the roof's design.

Talk about irresponsible.

I can't see that the walls require the roof, or any upward pressure on it,

I'm not 100% knowledgeable on the architectural engineering behind BC Place, but if I understand Jim's point properly -- and I welcome any correction he has to what I'm about to state -- the positive pressure inside the building, when the roof is inflated, pushes outward on the walls. This is like how all points on the surface of an inflated toy balloon are stretched in different directions, away from its centre. Given enough time, it's not impossible that this could slowly knock the walls over, so you extend the building's lifetime by tilting them inward a bit to compensate for this (i.e., the building isn't cylindrical, even in a rough approximation, but has a slight vertical taper). At the same time, this requires that the roof be inflated since otherwise, those inward leaning walls will conversely be less stable over time.

as the walls seem to be doing fine right now without any upward pressure, and there would have been no upward pressure in the first place while the roof was being constructed.

As I suggested, it's a gradual effect, mitigated by the fact that since 1982/3, the roof has spent far more time inflated than not. If the roof had never been installed with the walls constructed as I described above, BC Place might well have caved in by now, but I don't think it would have happened overnight.

The roof adds nothing to the walls, except load.

It does add a load, which I suppose would complicate the design of the building, but I think the positive pressure exerted on the inner walls would also be a consideration.

I'm still curious where this idea comes from. IMO, the pressurized roof would create uplift on the exterior walls of the stadium. When the roof is deflated as it is now, there would be inward pressure at the top of the exterior wall. The walls would have to be engineered for either load. Many building components in many types of construction are engineered for the forces placed on them during construction which may never be met again during the life of the building. In this case it would have to be expected that the roof could be deflated for periods of time for maintenance or replacement of the roof. Right now the building exterior is under greater loading than normal, and should the roof structure be removed those loads would be less, meaning that the building would be just fine without the roof in place, structurally speaking. I'm not an engineer, but have worked in construction for many years so I'm interested in the origin of the idea that the roof is structurally required for the building's integrity.

[Jim Mullin]

I've been told that without the roof inflated it would be a slow process of three to seven years before stress fractures would begin to show in the structure.

Never passed that engineering degree, but it is what I've been told.

[sj-roc]

I'm interested in the origin of the idea that the roof is structurally required for the building's integrity.

My interpretation (right or wrong) of Jim's point was that the roof seals in positive pressure that is exerted outward on the walls, so that it would only play an indirect role; otherwise, as is currently the case, the air pressure is pretty much the same outside and inside, which is unstable over the long term if the walls are tilted inward. I'm just thinking about the physics of it from a very (over?)simplified POV.

I don't think the load of the roof helps directly, which we both seem to agree on.

[120dB]

Can someone please confirm that speakers fell from the roof during the collapse? I read that a worker saw that a speaker had fallen before deflation. And those are huge speaker towers. They don't seem big when you look up at them but now that they're hanging close to the ground, yikes!

If there were 30,000 people inside for a Lions game and that happened.... I don't even wanna contemplate the ramifications

[Lionut]

CTV had an architectural expert on who suggested they take the roof off now, and keep it off past the Olympics.

Who is this clown? Does he not know there's no drainage in the place? That the electrical is indoor standard? That much of what BC Place stages is dependent on having an indoor facility? Or that the walls which lean into the facility are supported in part by the upward pressure in the roof's design.

Talk about irresponsible.

Want to know what happens when the architects get carried away, and make plans on which the engineers have not yet signed off?

http://en.wikipedia.org/wiki/Olympic_Stadium_(Montreal)

[pinkfreud]

This whole mess can't be good for promoting upper bowl season ticket sales.

[Sharpo]

To touch on the leaky condo thing.. No one does anything, any common sense checking because everyone wants the work in 20 years.

The homes going up now its all *poop* safety stuff.

don't buy a condo, just rent


edit: multiple condos and "poly***" sites under my belt. same stuff.

$$$$$ reassessment in 5+ years.

[lion24]

is any of this mess going to carry over to the season or should everything be taken care of by then?

[Gerry]

I've been told that without the roof inflated it would be a slow process of three to seven years before stress fractures would begin to show in the structure.

Never passed that engineering degree, but it is what I've been told.

I'm not doubting that you've been told that, but I'm still interested in where that info came from. I've worked in construction for 35 years, and spent a lot of time with engineers and blueprints, and it doesn't make sense to me. My son has just completed a degree in civil engineering and although he doesn't have his P. Eng. yet, he is working for an engineering firm as an engineer in training, and he agrees with me. I'd like to know how your source figures that the roof contributes structurally to the rest of the structure. I don't think it does. It is a load only.

It's just a matter of interest, since we agree that this stadium needs a roof due to other factors in its design.