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RE: Negative Structures.

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This is similar to the construction of the "caissons" for the Brooklyn Bridge which was done by pressurizing the wooden caisson chambers while they were stacked with masonry, sunk to the mud line, hand excavated.  The pressurized chambers resulted in the workers becoming ill from "caissons disease" or as us SCUBA divers call it; the bends.

The scheme for the caisson construction was developed in the 1850's and 1860's by John Roebling who died in a construction accident.  His son Washington Roebling completed the construction and was himself stricken by caissons disease in 1872, but lived to see the bridge completion in 1883.

I believe that this was the first time this method of construction was used.  Back in those days you did not quit when the CD's were done.  Engineers also tended to die, and become crippled at the same rate as the construction workers.

Remind me to let someone else do construction observation.

Former iron worker and current engineer,
Harold Sprague
Krawinkler, Luth & Assoc.
4412 W. Eisenhower Blvd.
Loveland, CO 80537
Voice: 970 667-2426
Fax: 970 667-2493
Email: hsprague(--nospam--at)

-----Original Message-----
From:	Germaine, Bob/CVO [SMTP:bgermain(--nospam--at)]
Sent:	Thursday, April 02, 1998 4:16 PM
To:	'seaoc(--nospam--at)'
Subject:	RE: Negative Structures.

I believe the proper term should be "caisson" (not to be confused with
drilled pier).
Bob Germaine, PE

> ----------
> From: 	T. Eric Gillham[SMTP:gk2(--nospam--at)]
> Sent: 	Thursday, April 02, 1998 1:53 PM
> To: 	seaoc list
> Subject: 	Fw: Negative Structures.
> Yeah yeah yeah!
> I figured someone would actually read that post and comment on it!
> Actually, the reason why I included the -3 stories, besides perhaps
> piquing
> someone's interest, was because it was an interesting project (for Guam
> anyway).  The project was a pump station that extended 30' below grade. 
> Because the structure was located adjacent to the ocean, it would have
> been
> very difficult for the contractor to excavate and cast in place (water
> table at about 2').  So, we worked it out with the contractor and had them
> incrementally build the structure on grade, while digging it out from the
> inside so that it sank.  I believe there is a specific name for this type
> of construction method, but to my knowledge it was the first on Guam.  So
> THAT's why I listed it as a negative structure, FYI.
> T. Eric Gillham PE
> ----------
> > From: John Nichols <cejn(--nospam--at)>
> > To: seaoc(--nospam--at)
> > Subject: Negative Structures.
> > Date: Thursday, April 02, 1998 12:58 PM
> > 
> > Dear Dennis,
> > 
> > It has been an awful day.  I broke the hand brake cable, after breaking
> a
> > transmission cable and a return line on some sort of emisssion control.
> > 
> > I made a mistake on a tutorial problem yesterday.  
> > 
> > Our other car won't be back from the panel beaters  till next week.
> > 
> > Obviously God whereever she is decided to remind me that life is short.
> > 
> > Then I read an email on the seoc list and it brightened up my whole day.
> I
> > thought you might like it.
> > 
> > Structures he has worked  on (or supervised) range from -3 to 32
> storeys.
> > 
> > I always wondered what a negative structure looks like.  (Before y'all
> jump
> > down my throat I realize what the Engineer was trying to say.  But it
> was
> > just so humourouse I decided to share it.
> > 
> > John
> >