NC coastal condo building - condemned for steel corrosion 1

[SLTA]

http://www.islandgazette.net/news-1...ina-surf-condo-building-for-structural-issues

Absolutely watch the video. Yowza.

Please remember: we're not all guys!

 

[TerryScan]

And subsequent development on story:

http://www.starnewsonline.com/news/20170713/carolina-surf-condos-fire-being-investigated-as-arson

 

[JAE]

I noticed this comment:

"Inspection of newly discovered corrosion to the structural columns has revealed that the structural integrity of the entire southeast corner of the building has been completely compromised. The cross sectional area of the structural columns in question has been reduced to half of its original size and therefore half its intended capacity. The bolted and weld connections at the floor and balcony systems are entirely corroded away."

That isn't really true. If you lose half your section of a column, the buckling load would be reduced by more than half. With thinner flanges, etc. you could have way less than half capacity with localized buckling.



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[dik]

JAE:

Depends on the loading condition. If you lose half your area mid column your buckling load can be greatly diminished... at the ends, if pinned, not so much.

Dik

 

[msquared48]

If the steel columns / beams are part of a moment frame, the capacity could be diminished by 75% or greater laterally...

Mike McCann, PE, SE (WA)

 

[JAE]

Local flange/web buckling doesn't matter where along the member length.

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[dik]

JAE:

Agreed... as Mike noted for rigid frame construction; the localized buckling is a bit dependent on the moment at the cross section in play.

Dik

 

[MikeHalloran]

The math models might not accurately represent the condition where you can tear big pieces of the web out by hand.


Mike Halloran
Pembroke Pines, FL, USA

 

[TehMightyEngineer]

I haven't seen corrosion that bad since I stopped doing work for the local paper mills.

Professional Engineer (ME, NH, MA) Structural Engineer (IL)
American Concrete Industries

https://www.facebook.com/AmericanConcrete/

 

[ATSE]

It would be good if AISC commented on this corrosion, and how it could have happened?

In the 13th edition (and I'm sure other editions)of AISC Steel Construction Manual, the Corrosion Protection section under General states, "In building structures, corrosion protection is not required for steel that will be enclosed by building finish..." When is this statement not true?
Are the structural engineers / architects liable for assuming industry-accepted practice applied to their building, and coatings were not required.

Steel 0
Concrete 1

 

[MikeHalloran]

corrosion protection is not required for steel that will be enclosed by building finish..." When is this statement not true?

IMHO, when the "building finish" comprises stucco.



Mike Halloran
Pembroke Pines, FL, USA

 

[SLTA]

I think the building is from the 80s. Unless the then-applicable code required more, it would be hard to make the original folks liable.

Please remember: we're not all guys!

 

[msquared48]

Look to the cladding as a failure mechanism that compromised the underlying steel with potential liability for the cladding installer / designer involved here... Not the SE.

Mike McCann, PE, SE (WA)

 

[dik]

TME:

I've encountered chemical plants where birds could fly through the webs... worse than an OWSJ...

Dik

 

[SlideRuleEra]

The address, 201 Carolina Beach Ave. South, is (Atlantic Ocean) beachfront property. The corrosion in the photos is typical of long exposure to salt air with occasional submersion in sea water. In the past 30 years, the Carolina Beach part of North Carolina (near Wilmington) has had more it's share of tropical storm / hurricane hits and near misses including associated storm surge to flood parking area under the building with ocean water. MikeHolloran is right, with this type exposure, half the steel may be gone but what remains is really just glorified rust.

After flooding with salt water, architectural covering and coating just accelerate corrosion - year round high humidity together with the salt that remains in the coverings ensure that the steel stays both damp and salty.

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[hokie66]

No hope for this building. I trust there will be examination of other structures there, especially ones built like this. Hopefully, this will give the reinforced concrete industry a leg up. And certainly the hot dipped galvanizing industry. Not much help to the stucco finish folks.

 

[dik]

I wouldn't park underneath the building...

Dik

 

[itsmoked]

It could really give a boost to the multistory wood movement that's happening.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[hokie66]

itsmoked,
How so? Wood has to be connected with steel, and wood also deteriorates with moisture, so if the same cladding system is employed, wood would suffer the same fate.

 

[itsmoked]

Wood doesn't rust in a salt environment but you make a good point hokie66 about all the ties - though they're all galvanized .

Keith Cress
kcress -

http://www.flaminsystems.com