Design of Axially-loaded Piles: Experimental evidence from 400 field tests

This work is aimed at furnishing an experimental support to the design of axially-loaded piles, taking advantage of an extensive database of pile load tests carried out in different sites nearby Napoli, in South Italy. Experimental data consist of nearly 400 full-scale pile load tests, some of them reaching large values of settlement. Different construction methods, including Non-Displacement, CFA and Displacement piles, have been used. The main results of the work consist in furnishing experimentally-derived rules and indications for pile design. With regards to failure loads, mobilization curves relating properly normalized values of load and settlement are proposed as function of the installation technique; indications on the bearing capacity of piles as function of geometry and technology are also provided. Initial stiffness of piles is investigated, identifying a rule of thumb for a rapid assessment, function solely of pile diameter and valid regardless of length and specific properties of pile and soil material.