17 replies to this topic

[wolverine]

This is a thread to post pictures and thoughts about this beast that carries I-75 over the Saginaw River.

Wikipedia mentions that the bridge will close in 2011 for extensive repairs.  

Also, has anyone noticed the West facing side of the Southbound span?   There's a very large dip in the span that I never noticed before.  Talk about way out of alignment, it's not a gentle curve from deflection, rather a sharp bend that lowers several feet.  I know we are all familiar with teh dips and drops you feel when you drive over it, but what I saw today did not look good.  It appears there was repairs made on that section before.  There's also an exposed compression member beneath it.  Obviously if this posed any sort of danger, the bridge would be closed, but you can't help but wonder how long this bridge will be around.

Edited by wolverine, 27 March 2007 - 04:26 PM.

[Ka3kab]

As someone who absolutly hates driving over bridges, you bet yet sweet potatoes that I've noticed that dip.  The Zilwaukee in particular is my least favorite bridge I drive over on a fairly regular basis.  I have a few shots of it, not in this computer, that I can transfer over and put up sometime.

[wolverine]

Ah, but that dip isn't just one I felt, I could actually see it.  The elevation of the bridge is somewhat of an elongated arch, except the center of the arch section is dropping downward compared the other section which remain somewhat level.  The dip can definitely be measured in feet.

[nofunk]

The one memory I have of that bridge is breaking down on it in an RV when I was younger. And it was hot and I was up there for hours.

Needless to say, I don't feel too fondly for it. (Even though I realize it wasn't the bridge's fault for being so steep. Or is it??)

[wolverine]

I did a quick calculation based on my very limited knowledge in civil engineering.

TOTAL SPAN = 8000 ft  HIGHEST POINT = 125

Obviously we know the slope of the bridge is not completely linear, but curved.  Therefore, I'm going to calculate for where the slope is the steepest across 2/3 of the incline.

Total Span/2 = 4000 ft.
Solving for steepest section only (2/3)(4000) = 2666.7

Using trig I get an angle of 2.68 degrees.   A vehicular ramp should never go more than 11 degrees, although they sometimes do in parking structures with narrow footprints.  No vehicle should ever burn out on incline that's three degrees, even if it's a mile long.

No funk, you made me do all that work!!  I do too much for people.

[nofunk]

wolverine, on Mar 28 2007, 01:38 AM, said:

Nofunk, you made me do all that work!!  I do too much for people.

Now if you could just get some reference photos for us, that'd be great.  

I'm sure the problem was the junker RV we were driving. But I still don't like the bridge.

[dtown]

I actually sort of like the Zilwaukee. When im in a truck i can see over the edge, so thats pretty cool.

I havent been on her in a while. So this one is seriously measurable in feet?

Last Summer:

Edited by dtown, 29 March 2007 - 01:54 PM.

[wolverine]

Very cool image I found on Michigan Highways



Note the old rampways to the original bridge.

[dtown]

I dont see anything?

[wolverine]

I meant to look at the grading of the Earth, you can make out where the old ramps used to be.

[Ka3kab]

I see them.  Its hard to forget where they are once you've had to sit next to them for almost 45 minutes waiting for a freighter to pass sitting in a car in the middle of July when its almost 100 degrees out (even if you were only 10 years old).  

Dtown, here is another picture from the same site which annotates the original bridge.

Edited by Ka3kab, 06 April 2007 - 01:18 PM.

[dtown]

Yeah. I see it now( well duh, its drawn out in red for me).

I just drove over the Zilwaukee today.

[wolverine]

Bah, up in Saginaw right now, but the camera is back in Ann Arbor!  I wanted to take some pictures beneath the bridge tomorrow.  Guess that won't be happening.

[dtown]

BTW, i didnt notice any big dip in the bridge. Maybe i wasnt looking closley enough.

[wolverine]

Were you beneath the bridge?

[dtown]

No, i was on the roadway.

[TIMBUC]

wolverine, on Apr 6 2007, 06:55 AM, said:

I meant to look at the grading of the Earth, you can make out where the old ramps used to be.

[TIMBUC]

I want to find many color pictures of the building of the Zilwaukee bridge and the accident of 1982,besides the ones in the "Zilwaukee Bridge From the Beginning book"

Does anyone know where I can find them?



Thank you