Caltrans Type II Bored Pile and Connection to Column 1

[Vporrazzo]

We are construction foundations consisting of 2,400mm diameter bored piles, 14,000mm deep. Bored pile terminates at ground surface. Subsurface materials are a thin layer of silty sand followed by mostly weathered tuff for the length of the pile so will use bentonite or Supermud for drilling fluid. A single rectangular rc column/pier is to be erected from the pile which requires the column steel to be inserted into the pile for a length of 3,400 to 4,000mm. The problem is how to do this without having to waste a lot of concrete in the overflowing process of removing the upper layer of dirty concrete during the bored pile construction. Bored Pile concept is based on the Caltrans Type II piles.

Project location is a high seismicity area (Manila, Philippines) for an elevated guideway as part of a LRT project so no splicing in the potential plastic hinging zone is allowed.

 

[civilperson]

Only the top two or three feet of the tremie pumped concrete needs to be disposed of due to contamination of the drilling mud. This is standard and is not amenable to lessened volumes. If you try for a lesser disposable volume, take surface cores of the pier concrete to prove the F'c strength beneath the columns.

 

[Vporrazzo]

The program suggested by the piling contractor is to remove the upper 300mm (1 foot) of the concrete to eliminate any weak/dirty concrete however I think it will be more like 600-1,000mm (2-3 feet). We will see shortly I guess.