I'm not a structural engineer

They're the experts...they should figure this shit out.

As if this is the first time snow/ice thawed quickly with winds blowing on an infrastructure

Keep in mind some of the variables and correlations here that engineers and other decision makes would analyze:

(All data below is hypothetical and meant to illustrate a point)

Control factor: wet/icey weather temperature changing between freezing and low positive temperatures

Data on damaged vehicles on this day:

http://www.sumoflam.biz/Washington07...dlerBridge.jpg
Some bridge from the states, cable design: >10 vehicles damaged, bridge shut down temporarily

http://mw2.google.com/mw-panoramio/p...um/4833547.jpg
Alex fraser bridge: >8 vehicles damaged

http://www.vancouversun.com/7377841.bin
Port Mann Bridge w/ cables directly over roads: >60 vehicles significantly damaged by ice

With the previous 2 bridges, the ~10 vehicles damaged during similar weather may not be statstically relevant for it to make sense to be a poor design. It could be as relevant as ice chunks falling off a street lamp pole, which is unavoidable within reason. But over 60 (probably low 100's by now, the 60 number I got earlier today) is a huge figure. 6x the amount of whats considered tolerable. That's a huge number.

All things equal, besides the bridge design, there would be a *reasonable* amount of quantitative data for engineers to re-assess their design and consider it faulty. In this case, they would weigh the cost of repairing damaged vehicles, lost tolls, and economic disadvantages with the cost of the best possible solution to fix the bridge (eg, heat traced cables, a barrier over the bridge, etc). In addition, decision makers would look at a forecast on how frequently did this type of weather pattern happen in the past, and use that along with other variables to make a prediction on future weather forecasts.

http://www.vancouversun.com/7722765.bin

Now decision makers can say okay, rainy ice chunks of death will happen on this bridge every 2.5 years, but comes with an annual cost of $4 million dollars in damage, injuries, and a death or two. But even the most cheapest design change, that is expected to improve the design by 99%, will cost $380 million dollars. Well if the useful life expectancy of this bridge is 60 years, and the cost/benefit of a design change is realized at 95 years, it may be more worth it financially to pay out all damage/injury/death claims than to re-design the bridge.

The cost/benefit of this, plus I suppose a public opinion poll, hearing, or whatever, would all be factored into this equation.

The kicker: LOTS of red tape and paperwork before any of this happens.

But now think about this. If in this case decision makers choose the best option would be to let continue the bridge's operation without design changes, how shitty would you feel if a big chunk of ice killed one of your family members? Someone you cared about died so that the general public could save $15 every time they pass the bridge.

Sorry if this fact offends some of you but I'm just shedding light on reality. I may have gone too far. I may have gone a bridge too far.

They better fix this. We spent 500+ million on a roof for BC place for two semi-pro sports teams that use the stadium half the year. They better not try and save a few hundred mill which might result in lives being lost.

What's bolded is exactly it.
The weather is a giant factor that comes into play, yet they should still have those cable sheaths designed to a certain point where ice should not be able to build up on them. Because of this fact it has the ability to "rain icy death chunks."

They now have to figure out a solution.

@alpinestars: It's not the fact that they look at it being a $4million annual cost to pay out the people injured, it's downtime.

If they close the bridge for 1 day a year because of this annoying occurrence. That could translate into way more then $4 million. Assuming 250,000 people cross this bridge a day, that would be 250,000 x 3 = $750k. Plus any more lawsuits, court costs, lawyers, etc. for the injured parties. (And that's for just 1 day.. We get snow more then 1 day a year)

I think the toll might go up once they figure out the solution. :pokerface:

You left out one major factor: hindsight is 20/20.

There are dozens if not hundreds of bridges of this basic design (tower/cable stayed) in the world, some (many?) of them with cables over the roadway, most without. Some are in warmer climates, some colder; some will experience snow and ice, some won't. Most have been in operation for years if not decades.

In all that, with a collective dozens if not hundreds of winters behind the design, it's apparent that a situation like this, to this severity, has not happened before - if it had, the design would have been modified to mitigate the risks, a long time ago.

So here you have a very particular combination of design and weather events that have conspired to create a very specific set conditions, quite possibly for the first time *ever*... so they were supposed to have planned for this based on, what... experience?

It's easy for all the armchair engineers to look at it now and say, "duh, why didn't they think of that?".

Death from above, the prequel

simple solution, huge nets above the roadway. temporary use, put them up in November, take them down in May.

now where is my million dollars?

:troll:

i still love the new bridge though. when it's not raining icy chunks of death it's a really nice drive.

Yea can't wait till summer nights for crossings :D
Posted via RS Mobile

Where did you get these statistics from?

Deductibles from damage caused on the Port Mann yesterday will be waived. Also, no tolls will be charged from 10am -6pm.

As per Mike Proudfoot, TI CEO

Wouldn't the nets also accumulate ice/snow as well? :P

Then you just put down another layer of nets, and so forth!

isn't there some sort of heated wire they can run on the cables? I'm thinking something like the rear window defroster lines. seems a lot more "cleaner" than giant nets =\

laser nets like in resident evil
http://www.technovelgy.com/graphics/...er-hallway.jpg

probably snow melt cables similar to ones used on parkade ramps

You heard it here first,

If they chose to do anything about the ICE CHUNKS OF NEAR DEATH, it will likley be to have a contractor apply a specialty coating to the cable sheaths.

This IMO, is the only logical means of attempting to fix the problem - taking finances into consideration.

EHT - Electronic heat tracing, this would cost huge moneys, and IMO it's not a practical solution due to the cost/difficulty to install/maintain. (You would also need to insulate the cable sheaths after EHT was installed)

there is already a coating to prevent this, but it didnt work.

Totally agree, the problem is that we are not talking about just 2 cables spaning the length of the bridge like the alex fraser or lions gate, we are talking about all xx amount of cables holding up the bridge span across the roadways, so all of them will need the EHT. It will cost millions to put up and maintain.

Cable Sheath Coating Rev 1.0?

any est. when it's going to be reopened?

...yesterday.

:suspicious:

They're waiting for Mike Holmes to show up. :badpokerface:

lol really? interesting

didnt keep a eye on update

Heated nets. Like heated seats.

Who needs engineers when we have RS to solve problems? :badpokerface: