Design of driven piles

[JDuk]

In my brief experience of driven pile design to date, it is clear that installation of driven piles in accordance with typical dynamic set calculations is regarded as a poor substitute to static design techniques. Many driven pile design calculation packages seem to include both a static design and dynamic calculation, with the proviso that piles will be installed to the static design length, or in accordance with the dynamic set, whichever occurs first. The static design will typically carry a F.O.S of 2.5 +, whilst the dynamic calc will carry a lower F.O.S of 2.0. Typically the piles will reach a dynamic set at shallower depth than required by the static design, at a depth that couldn't realistically be justified using static design principles, with perfectly satisfactory load test results (with the exception of false sets in sensitive materials).

My question is, has any research been carried out to allow for the dynamic affects of driven pile design installation, in terms of modification of the typical static design equations? My theory is that either the bearing factor should be modified upwards by a factor dependant upon the founding. Or the bearing capacity of the strata used to calculate the end bearing capacity of an individual pile is modified upwards to take account of the changes within the underlying strata under driving.

Are papers available discussing the above, or am I missing something altogether!?

Thanks

James - UK