Foundation, Concrete and Earthquake Engineering

Concreting in Pile Foundation (BNBC2006)

Dear reader we have few idea about pile concreting; here we like to include BNBC requirements for concrete in piling work. We know that concreting can be done by tremie method and drop bottom bucket. Here we will learn about which method is suitable for what types of piling work.

Our aim is to produce and place concrete in such way that it precludes segregation in bored or cast-in-situ piling operation. Here we will use deposit instead of placing of concrete, as in this case this word seems perfect.
Typical figure of drop bottom bucket for pile concreting
A continuous deposition of concrete is expected until brought to desire level. Top surface of concrete should be kept level (up to practical precision) and seam formation is avoided. The concreting method depends on diameter of bore hole. For a large diameter borehole, concrete depositions can be done either by

-tremie method

-drop bottom bucket

For a small diameter hole drop bottom bucket method is ignored and tremie method is adopted.

Now we like to include some slump value to have workable concrete that won’t get segregated:

In case of under-reamed piles, concrete should have slump of 100 mm.

In case of providing concrete in water free condition in borehole, the slump should be 150 mm.

In case of tremie concreting slumps of concrete are kept within (125-150) mm.

Dear reader there has some requirements of cement content and strength of concrete for different piling conditions and way to concreting, which we will learn in our next post.

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