Northbound Lake Shore Drive Bridge (in Chicago) Closed For ‘Structural Emergency’

[MrHershey]

[URL unfurl="true"]https://chicago.cbslocal.com/2019/02/11/lake-shore-drive-bridge-structural-emergency/[/url]

 

[EdStainless]

Built in '86 or 'modified in '86'?
I wonder when it was shimmed, that should have been a red flag right there.


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P.E. Metallurgy, Plymouth Tube

 

[IRstuff]

Found this picture, which seems to suggest that it's been really bad for a long time:

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert!

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[JAE]

Yes, when there's rust on the edge of the fracture - not a good look for the bridge inspectors.

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[IRstuff]

I kept wondering where the other cracked beams were; it turns out one of them was hiding behind the one in most pictures:

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert!

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[charliealphabravo]

For that connection to even work on paper it seems like there should be horizontal flanges/stiffeners at the seat, going at least the depth of the seat back into both beams.

 

[JAE]

Shored it up - jacked it back level - weld on some plates - open to traffic.

Chicago's Lake Shore Drive Bridge Closes for Emergency Repairs, Reopens With Temporary Fix

https://www.enr.com/articles/46384-...-emergency-repairs-reopens-with-temporary-fix

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[itsmoked]

Hows that work with the current cycling temp extremes?
Wish the pic showed the problem area.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[thebard3]

Why do those shoring towers look like they're riveted together?

Brad Waybright

It's all okay as long as it's okay.

 

[LionelHutz]

I thought that too Brad. The speed they appeared makes it likely they already existed just for that job. Did they have to fix this bridge before?

 

[Lomarandil]

No way guys... those are pre-fabricated, modular, bolted shoring towers. You'd have to call around for towers able to carry these kinds of loads, but in a town like Chicago, they're sitting in some contractor's yard somewhere.

As far as temperature effects... most towers are flexible enough to not offer a lot of restraint/stability in the longitudinal direction. They're only there for vertical support. Presumably, the longitudinal load path wasn't affected by this failure.

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