Pile rehabilitation

In late 2002, the Roads and Traffic Authority of NSW (RTA) approached CEEFC for assistance with a structural problem that is affecting a number of its bridges. These bridges were relatively new bridges that were constructed using concrete piles that suffered from a serious decay mechanism known as Alkali Aggregate Reaction (AAR). This mechanism caused expansive forces within the piles which eventually led to large cracks at the pile surface. These cracks resulted in serious corrosion of the reinforcement, in particular in submersed piles. This mechanism was significantly well understood to be largely prevented in new structures, but many existing bridge structures required major rehabilitation. 

Later the Queensland Department of Transport and Main Roads also became actively involved in this project as they have a number of bridges with similar problems. The CEEFC team developed a fibre composite pile wrap concept that can be applied to submersed piles. The team constructed a number of prototype pile wraps and a series of underwater trials were conducted to test the effectiveness of the concept. A special pressure test was also carried out to establish that the concept could sustain the required high pressure loads.

These tests have shown that the wrap exceeds the stringent requirements. Large scale production techniques are currently being developed in collaboration with a private company at the Gold Coast and installation of the first 100 fibre composite casings at the Missingham Bridge in Northern NSW is planned for the second half of 2004.

Project partners

CEEFC, USQ
Roads and Traffic Authority NSW
Department of Transport and Main Roads, QLD

Project coordinator

Dr Tim Heldt