A field trial of a reusable, hollow, cast-in-situ pile

Abstract

This paper describes the concept and field testing of a hollow, cast-in-situ, rotary bored pile foundation 1200 mm diameter and 30 m deep. The aim of the foundation is to allow large-diameter piles to be constructed using less concrete than in an equivalent conventional solid pile, and with a view to allowing reuse at a later date. Reuse is made possible because the hollow core of the pile allows access for inspection after demolition of an existing structure. The new piles may also allow modification to enhance load capacity by augering through the base and extending their length. In addition, the piles are better suited than conventional piles for use as ‘energy piles' to allow environmentally friendly heating and cooling. The geotechnical performance of the hollow test pile was comparable with that of a conventional solid pile constructed during the same trial. Details of construction are given, including lessons learned.