Development of a GIS system to assist in the management of underground structures that are at risk from corrosion and degradation [abstract only]

Thirty seven years ago the "Hoar Report" was commissioned to evaluate the cost of corrosion to the national economy of the UK. The report estimated the cost to be approximately 3-4% gross domestic product (GDP). Since then, the development of new construction materials and methods has reduced this cost to an estimated 2.5% - 3.5% GDP (DTI, 2000) indicating that whilst corrosion is being managed more effectively, it is still a significant concern and cost burden to the nation. In recent years, public and media interest has focussed on the costs of leakage from water supply pipelines, but all buried assets, whether pipe work, cabling, sewers or building foundations, present their own challenges as the problems are largely hidden from view and are therefore difficult to assess and manage. Corrosion of buried assets is caused by complex electro-chemical reactions between the construction materials of the asset and the surrounding ground . These reactions being controlled by the presence of potentially corrosive agents and naturally varying environmental conditions. With improved knowledge of material characteristics, and the increasing availability of digital data for soils, geology, topography and groundwater, new methods of assessing the corrosion risk are being identified. This has resulted in novel ways to prioritise underground assets, thus reducing management costs and service disruption, and optimising maintenance budgets. BGS is developing datasets and software to assess corrosion risk for a range of buried assets that might be subject to corrosive attack or degradation. The data and software not only provide information and an assessment of existing structures but can also aid initial ground investigations and guide infrastructure design in new developments. The challenge for BGS has been to combine national-scope, local-scale geological information into a GIS and create a simple, readily understandable asset management tool for the UK market. The buried asset management tool utilises background datasets relating to chemical causes of corrosion such as sulphate and chloride content, permeability and groundwater level data. The system also incorporates physical hazards, such as swell-shrink capacity, dissolution and landslide risk. In addition, the system is being developed further to include electrical conductivity assessments and also the presence of potentially harmful element concentrations such as arsenic, cadmium, chromium and lead. The simple to use system is designed to deliver information for assets buried down to 15m below ground level and the output comprises a detailed report highlighting the presence of potential hazards and their effect on a range of construction materials. Users will be able to use the information to assess the risks to assets, either as a means to prioritising maintenance and liability, or as a means of improving design for new installations.