Abstract:
Driven pre-stressed concrete piles have been used as a foundation system to support abutments and
piers of a bridge constructed near Ballina in New South Wales, Australia. In order to achieve the required
geotechnical capacity, the piles were required to be driven through soft clay and sand to moderately weathered
rock. Pile Driving Analyser (PDA) testing together with CAPWAP analysis was performed to assess the
integrity and geotechnical capacity of the driven piles. Pile damage was observed during driving. To prevent
damage a rock shoe was retrofitted to the piles prior to installation. Reductions in pile capacity (or relaxation)
were observed between end of drive (EOD) and later restrike testing (RST). A substantial amount of additional
pile testing was performed at different times after driving to assess the changes in pile capacity over time. Most
piles were re-driven to achieve higher capacity. Pile capacity could not be achieved in one pier and additional
piles were installed to reduce the required pile test load
