Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

11 Foot 8 – The Can-opener Bridge

11foot8.com

Post reply on HN
Print view View original

141–150 of 216 posts

Re: 11 Foot 8 – The Can-opener Bridge

#141

Post by bewaretheirs »

cam_l wrote: post #114
Animats wrote: post #53

The Sidney Harbor Tunnel had a similar problem. They came up with an elaborate but successful solution.[1] There are detectors and huge flashing warning signs that light up. Then, there's the last-chance sign. At the entrance to the tunnel, pumps force a curtain of water straight down across the entire roadway. Then a powerful laser system projects a giant octagonal red STOP sign onto the water curtain, filling the e…

I never understood the high-tech approach to this problem. Where i am from they have large metal tubes dangling down a ways in front of the bridge. Makes it sound like you have already hit it. Another more insistent approach I have seen elsewhere is to mount a large steel bar across the road, which takes the top of the truck off before they hit the bridge. (edit:not very simple problem, obviously..)

The 11'8" bridge has your second option: a heavy steel beam mounted a couple yards ahead of the bridge, braced to absorb the impact required to cut the trucks down to size.

It's more obvious in footage from the camera located on the left side of the bridge.

Re: 11 Foot 8 – The Can-opener Bridge

#142

Post by lysp »

joshschreuder wrote: post #138
Animats wrote: post #53

The Sidney Harbor Tunnel had a similar problem. They came up with an elaborate but successful solution.[1] There are detectors and huge flashing warning signs that light up. Then, there's the last-chance sign. At the entrance to the tunnel, pumps force a curtain of water straight down across the entire roadway. Then a powerful laser system projects a giant octagonal red STOP sign onto the water curtain, filling the e…

Melbourne, not to be outdone by our rivals, have the Montague St bridge which is frequently doing in trucks. Even has its own Twitter account, because of course it does: https://twitter.com/MontagueStBridg/status/12197515386602332... https://twitter.com/MontagueStBridg/status/12068168482782535... https://twitter.com/MontagueStBridg/status/11919444569053306...

Yep! And Montegue Bridge is even smaller - 3.0m (9 foot 10)

It also website counting when it last was hit:

https://howmanydayssincemontaguestreetbridgehasbeenhit.com/

With full history:

https://howmanydayssincemontaguestreetbridgehasbeenhit.com/h...

It's also a bit hard to miss:

#1 - multiple big coloured signs

#2 - bright rubber things that will hit your truck and make a noise

#3 - sign, flashing lights and stripe across bridge.

https://i.imgur.com/kYwsgEZ.png

Re: 11 Foot 8 – The Can-opener Bridge

#143

Post by ddingus »

Animats wrote: post #53

The Sidney Harbor Tunnel had a similar problem. They came up with an elaborate but successful solution.[1] There are detectors and huge flashing warning signs that light up. Then, there's the last-chance sign. At the entrance to the tunnel, pumps force a curtain of water straight down across the entire roadway. Then a powerful laser system projects a giant octagonal red STOP sign onto the water curtain, filling the e…

That water display is excellent!

Great engineering on what appears to be a tough problem.

Re: 11 Foot 8 – The Can-opener Bridge

#144

Post by numpad0 »

notatoad wrote: post #110
loeg wrote: post #105

Earlier quoted context omitted.

Or a wedge barrier: https://eci-illinois.com/wedge-barrier-versus-medium-size-tr...

i think the point is to prevent damage to trucks, not to completely destroy them

no the point is to prevent damage to road thus preventing a mini catastrophe like an underwater tunnel collapsing

Destroying the truck is indeed overkill though

Re: 11 Foot 8 – The Can-opener Bridge

#145

Post by numpad0 »

cam_l wrote: post #114
Animats wrote: post #53

The Sidney Harbor Tunnel had a similar problem. They came up with an elaborate but successful solution.[1] There are detectors and huge flashing warning signs that light up. Then, there's the last-chance sign. At the entrance to the tunnel, pumps force a curtain of water straight down across the entire roadway. Then a powerful laser system projects a giant octagonal red STOP sign onto the water curtain, filling the e…

I never understood the high-tech approach to this problem. Where i am from they have large metal tubes dangling down a ways in front of the bridge. Makes it sound like you have already hit it. Another more insistent approach I have seen elsewhere is to mount a large steel bar across the road, which takes the top of the truck off before they hit the bridge. (edit:not very simple problem, obviously..)

In their defense, the metal crash beam on 11’8” bridge is visually very discreet that I wasn’t sure if there is one from YouTube videos.

Re: 11 Foot 8 – The Can-opener Bridge

#146

Post by greggman3 »

NobodyNada wrote: post #19
chrisseaton wrote: post #10

What is so special about this bridge? Why do people drive under it without checking their height? You wouldn't normally think you can just drive under any bridge, would you? It doesn't even look like a very low bridge. Why do people approach it without a care in the world at full speed? My vehicle is only 2m tall and I still do take a quick look at height signs as I approach them.

According to the Wikipedia article [0], the bridge is very old and does not meet current clearance standards: > It was designed in the 1920s, and opened in 1940, with a clearance for vehicles of 11 feet 8 inches (3.56 m). This was a standard height at the time it opened. The standard clearance, since 1973, has a minimum height of 14 feet (4.3 m), which is 2 feet 4 inches (0.71 m) higher than the bridge as built. I im…

I ruined the top of a rental truck. It wasn't bridge it was a tree overhanging the street. Partly because the tree was not directly overhead like a bridge I didn't notice it was too low and all I was trying to do is park the truck so I was going slow but yea, smashed the top of the truck. Truck Rental company says it happens at least one a month.

https://photos.app.goo.gl/Q6QS9Uy3HNijYXEt7

Re: 11 Foot 8 – The Can-opener Bridge

#147

Post by function_seven »

sebastien_bois wrote: post #129
function_seven wrote: post #127

Earlier quoted context omitted.

The placement would have to be on a street where tall trucks are currently allowed. So now they can’t traverse the other nearby streets, even if they had no intention of using the underpass.

Ultimately I think the proper solution would be either far more clearance, or a dedicated lane for trucks/large vehicles (probably ALL trucks) forcing them to turn. The casualty of that solution might be buses (as others pointed out this road is also being used for), but the city can make exceptions for those (as is usual in most places due to stops being commonly in the right turn lane). It's clear from the massive…

Hey, I take back my rejection of your idea. I just saw someone else post this image [0] of a similar situation in Australia, and seems like that would work just fine, even for tall trucks that are gonna turn anyway. Make those dangly bits out of a weighted pool noodle.

[0] https://imgur.com/kYwsgEZ

Re: 11 Foot 8 – The Can-opener Bridge

#148

Post by Thorrez »

SenHeng wrote: post #54
aidenn0 wrote: post #25

Earlier quoted context omitted.

This is America. People have pickup trucks that have been raised to a height above 2m (about 6'6" in American)

And thus the presumably unstoppable forces meets the immovable object.

Is the goal to reduce crashes or increase them?
Post reply on HN