Historic Caisson Construction Methods
Historic Caisson Construction Methods
(OP)
I am currently working on a project in Chicago in which we are trying to determine the capacity the existing foundations. The 10-story building was built in 1911 and one was on of the first reinf concrete buildings. It was discovered that the foundations are concrete caissons. It was also determined that the caissons do not go down to bedrock, but rsst on clay 60 feet below grade.
Given the caisson shaft diameter at the basement level, it appears the diameter is not wide enough to support the building. My question is........in 1911, were they physically able to form bells or some sort of stepped foundation at the base of the caisson to spread the load on the clay? Or did the shaft get wider, as it went deeper?
Are there any historic resources that would discuss caisson construction from this era? Your help would be much appreciated. Thanks.
Terry
Given the caisson shaft diameter at the basement level, it appears the diameter is not wide enough to support the building. My question is........in 1911, were they physically able to form bells or some sort of stepped foundation at the base of the caisson to spread the load on the clay? Or did the shaft get wider, as it went deeper?
Are there any historic resources that would discuss caisson construction from this era? Your help would be much appreciated. Thanks.
Terry






RE: Historic Caisson Construction Methods
But I remember looking through some old boxes of photos and I remember there was a photo of four guys sitting at a card table, smoking and playing cards. The cool thing was, they were at the bottom of a pier shaft that was belled out quite wide. I think the photo was taken some time between 1920 and 1930.
I know this doesn't align with your 1911, but they did bell out piers back then, by hand labor - sounds quite dangerous - but in south Texas they have lots of highly plastic clay above a blue shale. So I guess the bells were stable enough.
RE: Historic Caisson Construction Methods
Also see other "old" books - Krynine and Judd's book (1957). Also see Tomlinson's book - especially the earlier editions. He has great chapters on well and caisson foundations (box bridge ones). I would also do checking in the older Engineering News-Records - they have had a lot of good info when I was researching a project from 1916.
RE: Historic Caisson Construction Methods
RE: Historic Caisson Construction Methods
After exposing the top of the caisson in the basement, the original vertical wood plank forms were found, as was described above in the "Chicago Method." Very interesting stuff!