For the structural engineer types.

[HankB]

Given the gap, it looks like the two sides were pulled apart, suggesting they were under tension. (Unless some sort of deformation took place after the break to create the gap?)

[KD5NRH]

They need to do a lot more than just fire up the welder and stick the two pieces back together.

Meh; it's New Jersey.  A couple dozen tubes of JB Steelstik putty to fill the gap and call it good enough for another 50 years.

[bedlamite]

Rub some dirt bacon on it, it'll be fine

FTFY.

https://www.youtube.com/watch?v=wSReSGe200A

[Hawkmoon]

OK, your enhanced picture does show what appears to be an H beam.

That said, it's not uncommon for the top chord of the truss to be multi-part flat stock connected by supports for bearing members for the deck above.

I'm convinced -- I'll accept that it's probably a wide-flange. But Mike, in fact it would be VERY uncommon for a heavy truss like this to be made up of flat stock. I say that as a licensed architect who had graduate-level courses in structural design and who works for an engineering firm that designs and inspects ... bridges.

[Brad Johnson]

I'm convinced -- I'll accept that it's probably a wide-flange. But Mike, in fact it would be VERY uncommon for a heavy truss like this to be made up of flat stock. I say that as a licensed architect who had graduate-level courses in structural design and who works for an engineering firm that designs and inspects ... bridges.

... and now we know who to blame. 

Brad

[K Frame]

I'm convinced -- I'll accept that it's probably a wide-flange. But Mike, in fact it would be VERY uncommon for a heavy truss like this to be made up of flat stock. I say that as a licensed architect who had graduate-level courses in structural design and who works for an engineering firm that designs and inspects ... bridges.

I didn't realize that this was on the approachways to the bridge proper, and is thus significantly larger than what I've seen.

What I described was apparently an older style construction technique for short span bridges (think across a culvert or stream, not across a major river). I saw it in a number of 1930s-era bridges in Central Pennsylvania.

Saw them when I was doing structure photography for my Father, who was a civil engineer and was inspecting bridges.

That bridge in New Jersey is actually mild compared to some of the things I saw... Or in the case of badly degraded bridges, didn't see... 

[KD5NRH]

I'm convinced -- I'll accept that it's probably a wide-flange. But Mike, in fact it would be VERY uncommon for a heavy truss like this to be made up of flat stock. I say that as a licensed architect who had graduate-level courses in structural design and who works for an engineering firm that designs and inspects ... bridges.

Meh; engineers are pathetically inefficient.  Even the newest tech can take apart something designed by an engineer and put it back together with parts left over.  It was probably the weight of extra parts that broke the bridge.

[Scout26]

... and now we know who to blame. 

Brad

Fistful !!!!

[230RN]

Thanks for the enhanced photos.  I wondered why they might be using a flat plate, so that clears up that mystery.  Like others, I could see no webbing in that original underneath photo.  H-beam it is, possibly for side-to-side stresses from wind or whatever.  I still think it was the whole bridge shrinking in cold weather and they should have put an expansion (contraction) joint there.  Either that or land settling toward the river putting the thing under tension.  Or both.

Must have made a hell of a racket when it finally popped.

[AmbulanceDriver]

I was just thinking the same thing Terry.  Musta been one helluva loud bang when that thing snapped.

[never_retreat]

Ok I'll agree H beam. We have not had any stupid cold weather.
Maybe 2 weeks ago we hit 10.

[Hawkmoon]

... and now we know who to blame. 

We didn't do that bridge. And in 1956 I was still in grammar school.

[Fly320s]

We didn't do that bridge. And in 1956 I was still in grammar school.

Which is why the bridge broke.  Children shouldn't build bridges.

[K Frame]

We didn't do that bridge. And in 1956 I was still in grammar school.

See if you can get your tuition back.

Your grammar stinks. 

[Hawkmoon]

Your grammar stinks. 

Oh, yeah? Yer mudder wears combat boots!

(I never knew just what that was supposed to mean, but back in the 50s that was a HIGH insult.)

[K Frame]

Oh, yeah? Yer mudder wears combat boots!

(I never knew just what that was supposed to mean, but back in the 50s that was a HIGH insult.)

My guess is that, given that combat boots were VERY cheap on the surplus market, it's a double dig that she has no fashion sense and she's too poor to afford anything else (having missed out on the WWII kicked the Great Depression outa here thing).

[makattak]

Oh, yeah? Yer mudder wears combat boots!

(I never knew just what that was supposed to mean, but back in the 50s that was a HIGH insult.)

I have heard (and I checked to see that the origin is at least in dispute) that the... err... "comfort women" of the armies in WWI and WWII would follow the camps and trade "favors" for clothing, among other things.

[K Frame]

Hum... interesting.

Sent from my SCH-I545 using Tapatalk

[MechAg94]

Given the gap, it looks like the two sides were pulled apart, suggesting they were under tension. (Unless some sort of deformation took place after the break to create the gap?)

So I am assuming elevated stress and likely a lot of day/night movement and load variations due to traffic meaning some combination of increased stress and fatigue? 

Most of the failures I have seen are almost all fatigue/corrosion, but most of our stuff either rotates or reciprocates. 

[Tuco]

Bridge collapse pron:

https://m.youtube.com/watch?v=CsKKDLKYsVU

[Hawkmoon]

Bridge collapse pron:

https://m.youtube.com/watch?v=CsKKDLKYsVU

I've seen that one many times. However, the reporter is in error -- the Whitestone Bridge in NY was not a twin.

Trivia question: What band did they get to serenade the death throes of the bridge? I'm sure the accompanying music made the collapse much more drmatic.

[230RN]

So I am assuming elevated stress and likely a lot of day/night movement and load variations due to traffic meaning some combination of increased stress and fatigue?  

Most of the failures I have seen are almost all fatigue/corrosion, but most of our stuff either rotates or reciprocates.  

Well, in this case, part of the bridge reciped one way and the other part rocated the other way.