71 replies to this topic

[tony]

How come one part is green and the other part is brown?

Money. Even though it's a bike-ped bridge, in our auto-centric world, the motorists' view is apparently the one that counts!


Since I don't see any photos of the bridge going up, here's a couple:
[attachment=2662:IMG_2620_small.JPG]
[attachment=2663:IMG_2628_small.JPG]
[attachment=2664:IMG_2634_small.JPG]
[attachment=2665:IMG_2639_small.JPG]
[attachment=2666:IMG_2683_small.JPG]

[chris v]

Awesome!

[mylo]

Money. Even though it's a bike-ped bridge, the motorists' view is the one that counts!

Since I don't see any photos of the bridge going up, here's a couple:

So you're saying the brown part is basically "unpainted". Didn't they have to paint it brown? Is brown paint cheaper than green?

[chris v]

So you're saying the brown part is basically "unpainted". Didn't they have to paint it brown? Is brown paint cheaper than green?

It's not unpainted... that would rust almost instantly.

[camay2327]

If I am not mistaken, the original design photos show artwork on the outside of the bridge. I guess that will come later if they are going to do it.

[Chad Vander Veen]

speaking of questionably needed bridges, what's with the two new pedestrian bridges being built over 50, right next to existing pedestrian bridges?

[chris v]

speaking of questionably needed bridges, what's with the two new pedestrian bridges being built over 50, right next to existing pedestrian bridges?

I know that for one of them it is replacing a non ADA compliant bridge.

[tony]

So you're saying the brown part is basically "unpainted". Didn't they have to paint it brown? Is brown paint cheaper than green?

Yep, it's called "weathering steel". It develops a light rust coating which, in theory, protects the steel from further corrosion. Almost all of the other steel trail bridges in town are also weathering steel. The green, you have to paint (unless that's copper!)

[chris v]

Yep, it's called "weathering steel". It develops a light rust coating which, in theory, protects the steel from further corrosion. Almost all of the other steel trail bridges in town are also weathering steel. The green, you have to paint (unless that's copper!)

It looked more like a brown primer to me... hmmm, now I have to ride back over there and check it out again.

[tony]

I know that for one of them it is replacing a non ADA compliant bridge.

Both, although there may been other reasons associated with the HOV lane project (Like vertical clearance under the bridges). In addition to not meeting ADA, both were very narrow and unpleasant at best to use.

Awesome!

Thanks!

As for the name...How about, the Bah Humbug Bridge? Kermit (it's not easy being green..and brown)? Or, you could just call it Tony (hey, that's the ticket!).

[MSgt]

What bike trail does it connect to on the east side of the new bridge.

[ekars]

What bike trail does it connect to on the east side of the new bridge.

You can find a great map of the bike trails here:
http://www.folsom.ca...ls/bike_map.asp

[tony]

What bike trail does it connect to on the east side of the new bridge.

It's teh continuation of the Humbug Creek Trail, which, unfortunately, currently dead ends behind the apartments on the south side of Blue Ravine just short of Oak Ave. Pkwy. However, it does connect to Folsom Middle School and to another bridge across the creek (that we fondly refer to as the "100 year old bridge" after one of the apartment dwellers who was at the bridge building) leading to Cummings Park.

[Bill Z]

Yep, it's called "weathering steel". It develops a light rust coating which, in theory, protects the steel from further corrosion. Almost all of the other steel trail bridges in town are also weathering steel. The green, you have to paint (unless that's copper!)

I'm sorry, but there is no "in theory" about iron rust protecting from further corrosion. Iron rusts, plain and simple, the rust grows and flakes off and corrosion continues.

Aluminum however is different, aluminum dioxide is harder than aluminum and it doesn't flake off, so aluminum will oxidize forming a thin skin barrier preventing further oxidation.

but steel and iron, I'm sorry, there is no theory that iron oxide provides any kind of protection to further corrosion. anyone that told you that doesn't know what they are talking about.

[tony]

I'm sorry, but there is no "in theory" about iron rust protecting from further corrosion. Iron rusts, plain and simple, the rust grows and flakes off and corrosion continues.

Aluminum however is different, aluminum dioxide is harder than aluminum and it doesn't flake off, so aluminum will oxidize forming a thin skin barrier preventing further oxidation.

but steel and iron, I'm sorry, there is no theory that iron oxide provides any kind of protection to further corrosion. anyone that told you that doesn't know what they are talking about.

Bill, I only said "in theory", because there have been problems with it in the past when used in particularly corrosive environs, like near the ocean or chemical plants. Sorry, but you're wrong on this one (I've been designing bridges for 25 years, starting in the Mecca of steel bridges, Pittsburgh, PA). Weathering steel (Most commonly ASTM A588, also known by its US Steel trade name, "Corten") has been around for about 45 years. It has a chemical composition that does, indeed, result in a uniform protective coating of rust that forms on the surface, preventing moisture from reaching the rest of the material so that it prevents the typical "packing" and flaking associated with typical steel corrosion. Some states (notably Michigan) started using it in the 1960s and had bad experiences because many of their bridges were in heavily industrial areas, and so stopped using it. So it was controversial in the industry for a few years, until the industry came up with better guidelines on where not to use it.

But, if you don't believe me, here's what the American Iron and Steel Institute says about it (granted, it's a little like reading BP's page on oil spills cleanup, but for purposes of this thread, they are the experts): AISI

Maybe Kerri would like to chime in on this one, since corrosion is her specialty.