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-   -   Widest bridge in the world (http://www.diyaudio.com/forums/lounge/220021-widest-bridge-world.html)

Cal Weldon 19th September 2012 03:50 PM

Widest bridge in the world
 
The new Port Mann Bridge at 65m (10 lanes) surpasses the Sydney Harbour Bridge of 49m.

Set to officially open in December 2012 (8 lanes), 3 lanes for east bound traffic are already in use as of yesterday. 10 lanes will open a year after the official opening as they have to demolish the old bridge before the last 2 lanes can be built.

Port Mann Bridge

dchisholm 20th September 2012 03:23 AM

Those cable-stay bridges seem to be quite popular right now - we have some here in the St Louis (Missouri, USA) region and one under construction over the Mississippi River. They certainly have a striking visual appearance. As Dr Henry Petroski said in his recent column "Everyone Loves Good Design", in DesignNews at < http://www.designnews.com/author.asp...dfpLayout=blog >:
Quote:

Unlike buildings, which hide their engineering behind architectural facades, bridges tend to lay bare their structural design features. The lines by which forces are directed and transferred are exposed and open to admiration, exploration, and fascination.
I'm surprised he didn't mention this Port Mann span.

Even so, when I see cable-stayed bridges, the multiple cables give me a nagging thought that it's an overly complex design. As with any design innovation there will probably be a failure at some point. This, in turn, will lead to better understanding of the design and even more capable implementations - as the 1940 failure of the Tacoma Narrows suspension bridge eventually resulted in the successful but much more challenging spans at Mackinac, Akashi-Kaiko, et al. We need to have faith that some alert engineers will identify potential failures and avert catastrophes.

Dale

p.s. - In case you haven't discovered him, Petroski is definitely worth reading for his perspectives on engineering philosophy and the design process.

nezbleu 20th September 2012 03:33 AM

I understand that when the fixed link to PEI was planned, there was a suggestion for a similar (although narrower) cable-stay bridge in the center section. The cables were to be painted a bright green, producing a "Span of Green Cables".

(Canadian joke, see Lucy Maud Montgomery)

Pano 20th September 2012 03:38 AM

All those people going somewhere. That's a lot of bridge!

chrisb 20th September 2012 04:13 AM

Quote:

Originally Posted by Pano (Post 3171641)
All those people going somewhere. That's a lot of bridge!



to Timmies for double-doubles and honey glazed crullers of course;)

as Cal or nezbleu would say, it's a canuck thing

all kidding aside, the egg white breakfast sandwich on English biscuit is not the worst way to start your day

PlasticIsGood 20th September 2012 05:54 AM

If the towers were thicker, they wouldn't need so many cables to hold them up.

It doesn't look very musical. If all cables contribute the same upward force, how are their frequencies related?

jan.didden 20th September 2012 06:03 AM

Quote:

Originally Posted by dchisholm (Post 3171633)
Dale

p.s. - In case you haven't discovered him, Petroski is definitely worth reading for his perspectives on engineering philosophy and the design process.

Just am reading Petroski's "To Engineer is Human - the role of failure in successful design". The cover has a great picture of that historical bridge failure. Great read, BTW.

jan didden

Cal Weldon 21st September 2012 08:43 PM

Quote:

Originally Posted by PlasticIsGood (Post 3171709)
If the towers were thicker, they wouldn't need so many cables to hold them up.

:D

Ron E 22nd September 2012 12:03 AM

Quote:

Originally Posted by Cal Weldon (Post 3173916)
:D

Minneapolis has a new 10 lane bridge, although for the purposes of your metric, it is probably 2x 30 meter bridges ;)

Cal Weldon 22nd September 2012 12:48 AM

If you look at it, I am guessing the 65m part is where it goes around the two towers.
It's the only cable suspension bridge that I've seen that uses 4 cables at each stage. We have others in the area with the more traditional 2 as much of the world does. As far as the widest bridge in the world part goes, we didn't heard that until recently, or maybe I hadn't paid attention. I have watched the bridge go up from my office window since day 1. Well actually for the first year all I heard was the pile driving which, in it's own right, was kinda cool. They used the, what I'm gonna call, the diesel type. Maybe someone can tell me what it's really called but it's the one that uses a fuel rather than a crane. The rhythm is faster so while I am doing my typing, it keeps me in synch. ;)

It's been a great thing for those of us who watch those Discovery channel or Nat Geo shows on this sort of thing. I am guessing it will be there one day.

Oh, and uh Ron...I am of the ilk that uses standard measures still, along with the metric, even though Canada went to metric uh, I don't know, 30+ years ago. I understand both but the tape I use when building things is still standard measure. Old habits die hard. :D

Cheers.


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