The objective of this project is to develop an integrated Decision-Support-System (DSS) for the rehabilitation planning of sewers that, based on CCTV inspection results will assess the structural reliability of the inspected sewers as a function of time taking into account sewer deterioration by the various degradation mechanisms (voiding of bedding and backfill, corrosive soils and groundwater, sulphide formation in the wastewater flow, corrosive and erosive industrial wastes), seismic forces and uncertainties (in the estimated wall thickness of the pipe, soil support, loading, etc.), select the best remedial measures, prioritise rehabilitation projects and schedule re-inspection.
This DSS will help municipal engineers establish a defensive planning strategy for sewer rehabilitation investments and help CCTV inspectors to offer a higher quality and more complete service to their clients.
to accomplish the above specific scientific and technical objectives of this project are:
- To develop a methodology to enable the structural reliability of existing, deteriorating pipelines during future operating conditions to be predicted taking into account the results of inspection with CCTV equipment, the type of soil, the water table, the pipe material and type of joints, the age of the pipeline, the loading conditions including seismic loads, if applicable, and environmental stressors giving rise to time-dependent degradation mechanisms, such as, corrosion, erosion and settlement of the underlying soil, and sulphate attack. This prediction will be updated when new data from inspections become available using a Bayesian updating procedure. Structural limit states will be determined in terms of an acceptable probability for structural collapse of a pipe cross-section.
- To develop a DSS for planning the rehabilitation of sewers. This DSS will prioritise rehabilitation based on the life expectancy of the sewer, compliance with the Standards, and financial and social considerations and select the optimum remedial measures. When rehabilitation can be postponed the above DSS will schedule re-inspection.
From the social point of view objectives of this Project are:
- To increase the competitiveness and transnational cooperation of SMEs in the sewer internal inspection industry.
- To decrease by 80% the engineering time to assess sewer condition and select remedial measures.
- To help compliance with the EU standard EN 752-2 on sewer structural integrity and water tightness and thus protect the environment.
- To reduce the likelihood of sewer collapses (currently at a level of 20 per 1000 km per year) and thus decrease the risk of street and other utility collapsing leading to flood and loss of life.
- To extend the life of sewers and reduce the lifecycle costs of sewer maintenance.