CONTINUOUS FLIGHT AUGER (CFA) SYSTEMS

[kkoloj]

We are currently looking into using a CFA system for a foundation design for a custom home. If anyone has some experience with such systems what are some good and bad points (e.g., effectiveness of installation, cost, time, etc.).

Thank you very much for any responses.

 

[kyoussef]

CFA is a very cost effective deep foundation system. Construction of this system is much quicker than the other systems. However, it requires very careful quality control. The drilling rigs should be equipped with special device to monitor the volume and pressure of the concrete or grout. It is also not suitable for some types of soil, e.g.; if one of the soil layers is soft clay. You did not describe the soil profile in your project. You can find helpful information in a TexDOT Report No. 3921-1 by Hassan et al.

 

[jgailla]

kkoloj,
Can you go into more detail about the CFA system. It sounds similar to augered cast in place deep foundations, which are commonly used through soft clays.

 

[PSlem]

The local man is about $17 per foot. Tests with SPT to be sure he is down to good. 8" piles. Won't do a job with less than about 50 piles or charges a mobilization fee so doesn't do standard houses, just big ones. Takes 3 days to do large house.

The optimist sees the glass as half full. The pessimist sees the glass as half empty. The engineer see the glass as too big.