What load defines pile failure?

[cliff234]

When load testing piles (pipe piles and auger-cast piles), what vertical settlement defines pile failure?

I seem to remember an older version of the IBC Code used to specfically define failure load as the load corresponding to 1” of vertical settlement - but I can’t find this anywhere. The allowable service load was equal to 0.50 x failure load. Does anyone else remember that?

Likewise, the failure load for lateral loading was defined as that load corresponding to 1” horizontal pile deformation, and the allowable lateral load was equal to 0.50 x failure load.

 

[jayrod12]

Is there a geotech on your project? If so, that would be a good place to start.

In the geotechnical reports I get they indicate that around 1% of pile diameter is a common serviceability limit state for end-bearing cast-in-place piles. But I'd expect for driven piles (also end-bearing) that 1% may be a different number.

 

[BridgeSmith]

...what vertical settlement defines pile failure?

Not trying to be glib, but my answer would be whatever is too much. By that I mean, the amount of settlement that is tolerable or acceptable depends on the structure being supported, and how much settlement would be detrimental to its performance. Piles supporting bridge abutments sometimes have different limits than those supporting piers, and piles supporting retaining wall footings typically are allowed larger settlement than either type of bridge substructure.

Rod Smith, P.E., The artist formerly known as HotRod10

 

[jaskamakkara]

Not trying to be glib, but my answer would be whatever is too much. By that I mean, the amount of settlement that is tolerable or acceptable depends on the structure being supported, and how much settlement would be detrimental to its performance. Piles supporting bridge abutments sometimes have different limits than those supporting piers, and piles supporting retaining wall footings typically are allowed larger settlement than either type of bridge substructure.

This is likely correct. Deformation generally constitutes a servicability limit state for the structure and these are generally down to the client requirements, but your local codes may impose upper limits that apply to all projects.