Historical overview of CPT-based design methods

The Cone Penetration Test (CPT) is used for many decades in order to evaluate the pile bearing
capacity. Pieter Barentsen developed the CPT around 1930 in order to investigate the soil
resistance. However, Boonstra was the first, in 1940, to used the cone resistance of the CPT as
the unit pile bearing capacity. From this moment, the CPT became very important in the
evaluation of the pile bearing capacity. An overview is given about the most common pile
design methods, which are based on the in-situ Cone Penetration Test (CPT). This overview
will start with the evolution of the CPT, followed by a brief presentation of the methods in use.
An important part, in pile design methods, is the averaging procedure of the cone resistance
over an influence zone around the pile tip. Since the pile tip is much wider than the tip of the
CPT cone, the influence zone of the pile is also much larger, therefore the cone resistance has
to be averaged over the influence zone around the pile tip. Unfortunately, the definition of this
zone is different for each method in use. Finally, several methods for the pile tip bearing
capacity near the interface of a soil layer will be discussed, including related methods from De
Beer [1] and White & Bolton [2].