What is a caisson?

[BadgerPE]

I just finished reading "The Great Bridge" which is about the building of the Brooklyn Bridge. A large part of the book focused on the caisson foundations used to support the the bridge under the East River. The caissons were constructed out of timber with a large hollow working area underneath where men worked to excavate the soil and sink the caisson to the proper elevation. Compressed air was pumped into the workspace to force the water out as the caisson sank lower and lower. Once the caisson reached the desired elevation, concrete was pumped into the workspace to create a solid foundation......this obviously isn't how it is done today, but I still hear the term caisson used. Can anyone explain what one is and how it is constructed.
Thanks much!

 

[oldestguy]

Go to a Google search for Vulcanhammer.info

Then, in the upper left corner do a search for"caisson".

They have many references that can answer the question, in part.

A Google search brings up some variations in the use of the word.

In that same light of differing definitions, try the word "topsoil".

 

[PEinc]

The Brooklyn Bridge caisson is just as you described. Today, at least on the east coast, the term caisson most oftem means a drilled, concreted shaft.

http://www.PeirceEngineering.com

 

[hokie66]

I would like to see the word 'caisson' reserved for the type of footings used in the Brooklyn Bridge. But over the years the meaning has evolved to mean bored piles, bored piers...whatever, and that varies from place to place.

 

[msquared48]

It's what a lawyer says when a potential client plops down the retainer.

Seriously though, I have always associated the word with larger foundation excavations where men and large equipment were inside doing the excavating. As Hokie said, as with the Brokylin Bridge. If I remember my history correctly, cases of the bends, or caisson disease, stemmed from this.

Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask

 

[Zambo]

Caissons are very much in use today.

A typical and common example would be shafts which are sunk to create chambers for wastewater systems etc.

Basically a caisson is a watertight box, or shaft, which will withstand external loads exerted by soil or water. A cassion can either be temporary works for men/machines to work inside or a permanent structure which is utilised as a construction method.

I have often seen the word used to describe bored piles, but in this case I don't know what word would be used to describe a "caisson"

 

[BigH]

In India, they use the term Well Foundations to mean "caisson". And I thought caissons were those carts drawn by horses in military artillery groups to pull the artillery piece and for munitions. How silly of me!!!

 

[hokie66]

They also call a military casket cart a caisson.

 

[RockEngineer]

And the hollow steel structures used to plug the end of a dry dock for ship building and repair is called a caisson. Isn't the english language wonderful in how one word can mean so many different things depending on where and how it is used.

 

[PEinc]

FYI, this web site for Case Foundation Company shows pictures of and refers to concreted, drilled shafts as "caissons."

http://www.casefoundation.com/projects/trumptower.aspx

http://www.PeirceEngineering.com

 

[csd72]

Where I come from caisson and coffer dam are pretty much the same thing.

 

[paganel]

The word "caisson" comes from the French,which means "box".
For the caisson in the early age, it only refers to the pneumatic caisson as you mentioned. In the enclosed shaft,excavation is carried out with high air pressue to balance the water pressure below the excavation surface below and the cassion itself would sink with the excavation.

However caisson is not used in Europe and States frequently nowadays since slong piles are more and more popular. But in Japan,there still are several contractors still developing this technology with some interesting ideas.
Could get some info here

http://caisson.shiraishi.com/outline/index.html

 

[PEinc]

Interesting web site but very hard to read!

http://www.PeirceEngineering.com

 

[paganel]

It is very pity most of these references are only with Japanese. But one file is attached, you guys can have a look of the construction procedure.