Load tests - Drilled Shafts.

The only positive way to prove the integrity  of a suspected drilled shaft is to perform a load test.  Drilled shafts are often constructed in relatively large sizes  and load tests are often not economically feasible.

Replacing  a suspected drilled shaft is often more economical than performing the load test.

(1)  Application. Shall be performed for drilled shafts when economically feasible such as for large projects.  Results of load tests can be used to reduce the FS from 3 to 2 and can increase  the economy of the foundation when performed during design.

(2)  Preload.  An alternative to load tests is to construct the superstructure and to preload the structure to determine the  integrity of the foundation.  This test must be halted immediately  if one or more drilled shafts show more settlement than is anticipated.