Concreting of Friction Caissons
Concreting of Friction Caissons
(OP)
How long should the hole be left open after drilling and before concreting?
The job involves a friction caisson with a socket in Shale rock. Shale tends to slake and weather on soaking. I was told that the practice in some states dictates that an open excavation should not be allowed to stand for more than 4 days or so.In this project, the hole is filled with water to balance the hydrostatic pressures in the hole. We sre going to run some durability tests on Shale.
DocDirt
The job involves a friction caisson with a socket in Shale rock. Shale tends to slake and weather on soaking. I was told that the practice in some states dictates that an open excavation should not be allowed to stand for more than 4 days or so.In this project, the hole is filled with water to balance the hydrostatic pressures in the hole. We sre going to run some durability tests on Shale.
DocDirt





RE: Concreting of Friction Caissons
In practice the bottom should be checked bewore lowering the reinforcement and cleaned if necessary.
RE: Concreting of Friction Caissons
DocDirt
RE: Concreting of Friction Caissons
RE: Concreting of Friction Caissons
DocDirt
RE: Concreting of Friction Caissons
Dik
RE: Concreting of Friction Caissons
For determining the load taken in friction and in baring, I use Figure 9.18 b, Page 371, from the text on Rock Mechanics by Goodman.
By the way, I did find some reference from Ohio DOT specifications regarding my question. It states that especially for caissons constructed by the wet method, if the hole is left open for more than 24 hours, hole has to be drilled an additional 6 inches and cleaned before concreting. In a job, I am involved now, where we are using friction caissons, we stipulated that if a hole is left open for more than 24 hours, the sides have to be roughened and the bottom cleaned before concreting.
DocDirt