Hollow precast driven pile extended by a micropile: dynamic load tests and modelling

The hollow precast driven pile (HCK) is a product developed by Rodio Kronsa. It consists of a concrete driven pile
with a square cross section of 300, 350 or 400 mm side, and with a coaxial circular hole of variable diameters. This
pile, just like any conventional precast pile, gets installed into the soil by driving the element until the hard material
is reached at the toe. After that, we can take advantage of the inside hole for different purposes. One of the most
frequent uses of hollow pile is to drill and install an inner micropile of a certain length below pile toe, through the
resistant soil. The goal of this article is to show the results of dynamic load tests carried out on this compound
element on a construction site. On site, some dynamic load tests were performed. After that, on the office, a
CAPWAP analysis was also carried out, by making a discretization of the pile and the micropile, introducing the
change of material at the pile toe. The compound pile was also modelled with finite elements and the results were
compared.