The Floating Bridge

[EddMarkStarr]

Would you drive on a bridge that floats on water, with no underwater supports?

Washington State has two floating bridges, the Interstate 90 Floating Bridge, and the SR 520 Floating Bridge (Evergreen Point Floating Bridge).

As part of the U.S. Interstate Highway System, there is no toll to cross the I-90 Floating bridge. The 520 Floating Bridge does charge a toll to cross.

I'll say it again, I should've been an engineer!

 

[unloadonme]

Maybe not on a stormy night, but otherwise yes I'd drive across that.

 

[Vannie]

I'll cross that bridge when I get there.

 

[pigface]

Unless there are abnormal water currents or defective construction, its no less safe than other bridges. Maybe safer, since the distance to fall is shorter when you drive off the middle of it.

 

[EddMarkStarr]

Unless there are abnormal water currents or defective construction, its no less safe than other bridges. Maybe safer, since the distance to fall is shorter when you drive off the middle of it.

The original Evergreen Point Floating Bridge had a road deck that was almost level with the water. Every windstorm would through waves onto traffic until DOT crews could shut-down bridge traffic. I don't remember any cars going over the sides into the water, but I do remember cars being tossed into each other, stranding traffic with accidents just when the bridge needed to be cleared.

 

[rareboy]

No reason it shouldn't work just fine...military forces have used pontoon bridges for a few thousand years to move their forces and equipment.

But I would think that storms would make them not much fun to cross if they are close to water level.

 

[cityboy-stl]

Sure, I would drive across it. It seems perfectly safe for now. But a few thoughts.

The beginning of the video said the lake bed was just clay and mud. But then they said they anchored the new bridge to the lake bed. How so?
What happens if there is some kind of major storm flood and the water level rises very high? Can the bridge handle that?
Conversely, there are lakes in the U.S. that are drying up due to global warming. If that happens, then what?

 

[pigface]

Conversely, there are lakes in the U.S. that are drying up due to global warming. If that happens, then what?

Well you don't need a bridge then - just drive across the salt flats!

 

[LeicsDom]

As it isn't on tidal waters I see no reason to be nervous

 

[Kahaih]

/\ Leeches, though.

 

[NotHardUp1]

I would not be afraid to drive across one.

Their application must be extremely limited as they obviously become a barrier to water traffic.

 

[EddMarkStarr]

I would not be afraid to drive across one.

Their application must be extremely limited as they obviously become a barrier to water traffic.

Yes, the original floating bridge had a retractable section for boat traffic. The new bridge forces boats to use the elevated sections at either shore.

 

[Kahaih]

Yes, the original floating bridge had a retractable section for boat traffic.

Did they have to warm it up when the water was cold?

 

[NotHardUp1]

Did they have to warm it up when the water was cold?

I'd be more worried about the smell in summer.

Yes, the original floating bridge had a retractable section for boat traffic. The new bridge forces boats to use the elevated sections at either shore.

Judging from the photo, the boats cannot be very large.

 

[EddMarkStarr]

Did they have to warm it up when the water was cold?

That's the most amazing thing about Lake Washington - the water never warms up! (most fatalities are summer swimmers who succumb to the low water temperatures of the lake)
The old retractable bridge had an operating mechanism that was cycled several times a week but kept the draw span in place for traffic.
When it was time to actually open the bridge, it was fast and operated without incident.

 

[EddMarkStarr]

I'd be more worried about the smell in summer.

Judging from the photo, the boats cannot be very large.

Yes, Lake Washington boat traffic is recreational, I'm not aware of any commercial vessels that operate on the lake.

I like the way the DOT describes it:
"the current Evergreen Point Floating Bridge (SR 520) does not open for boat traffic as it does not have a drawspan - the new design allows tall vessels to pass underneath due to higher sections at either end of the bridge, eliminating the need to open the bridge for boat passage"