Extending the life of essential sub surface assets, a practical approach to guarantee structural competence in pipeline and culvert rehabilitation.

Abstract

How can we guarantee that our remediation proposals will meet the structural requirements necessary to extend the life of our critical underground infrastructure assets when limited ground information and condition assessment is available? When considering a project for rehabilitation there are a number of technologies available that can be used to develop a design that achieves a solution that is fully compliant with Australian design standards however some of these carry more risks than others. The current design codes used for relining rehabilitation across Australia actually relate to new works construction. These standards are assimilated to reflect the conditions that are presumed to be present with the existing structure and surrounding soils however without specific factual data, ie a ground investigation report and condition assessment some of the assumptions made carry a significant risk that the design must accommodate or else premature failure could occur. How we mitigate his risk to ensure that the design proposal accommodates the contractual scope and duty that will be applied to the structure will be dependent on the technology that is being proposed and the factors around how much these methodologies are reliant on the assumptive criteria and therefore risk. Often when information is unavailable worst case scenarios are adopted which drive over conservative design and ultra-sensitive risk assessment. This then questions the efficiency of the proposal and the economics which in turn raises the effectiveness of a rehabilitation against a new build. This paper explores the current technologies available for structural rehabilitation of our critical sub surface infrastructure to current Australian Standards to achieve solutions that are compliant. It looks at how much risk needs to be accounted for and considers other international standards that could be applied to mitigate some of the unnecessary cost to provide fully compliant structural solutions that will last for in excess of 100 years.