The Evaluation of Pipe Performance and Durability

1. The Evaluation of Pipe Performance and Durability Stewart Burn CSIRO Urban Water Infrastructure Contact Stewart.Burn@csiro.au

2. Research Activity • CSIRO – 6500 scientists across Australia • 20+ working specifically on asset management of water systems • Water - PARMS • Sewers - CARE-S • Benefits from our Research • Improved Asset Management – Risk Based System • Reduced Failures • Appropriate service at optimal cost • Some return from our investment to invest in further

3. Asset Management Components

4. Asset management strategies • We consider the key Components of an Asset management strategy include • A Risk based methodology based on • Whole Life Costing methodologies to measure consequences • Models for predicting pipe failure • Statistical Models • Physical/Probabilistic Models

5. Asset management strategies

6. PVC Average failure rates (US/Canada)

7. PVC Average failure rates (Australia)

8. Statistical models • Standard failure curves developed for particular material, diameter, length, pressure, soil environment • 7 Australian water authorities assessed with 50 years plus of data, 17 UK authorities now being assessed - UKWIR • Statistical Models Need tuning to each authority • Currently seeing if generic curves exist • Developing Physical/Probabilistic Models in conjunction with AwwaRf

9. PVC pipes – CSIRO/AwwaRF • Physical/probabilistic model predicts fracture failures in the field • Linear Elastic Fracture Mechanics theory used to predict time to brittle fracture from pipe wall defects • Uncertainty in model variables accounted for using Monte Carlo simulations

10. Polyethylene (PE) pipes – CSIRO/AwwaRF • Increased ductility of current PE materials renders conventional linear elastic fracture mechanics theory invalid • The historical development of different PE grades adds further complication • Physical/Probabilistic failure model in progress and is supported by statistical models based on recorded failure data

11. Asbestos Cement pipes - CSIRO • Physical/Probabilistic model predicts degradation and loss of strength in the field • Failure predicted to occur under critical combined internal pressure and external loading • Uncertainty in key variables accounted for by Monte Carlo simulation methods

12. Statistical Physical prob. Cast Iron pipes – CSIRO • Physical/Probabilistic model predicts corrosion penetration through pipe wall • Failure predicted to occur under combined internal pressure and external loading at critical corrosion pit depth • Uncertainty in key variables accounted for by Monte Carlo simulation methods • Large volumes of historical failure data also allows statistical models to be developed

13. Ductile Iron pipes – NRC/CSIRO/AwwaRF • AwwaRf project in progress in collaboration with National Research Council, Canada • Will develop service life prediction models for Ductile Iron pipe • In-situ monitoring of corrosion damage in relation to soil electrochemical properties • Statistical methods used to extrapolate measured corrosion damage to longer lengths of pipeline • Physical/Probabilistic model to predict corrosion failure in different soil environments

14. Cement Mortar Lining (CML) CSIRO/AwwaRF • AwwaRf project in preparation to address the long term performance of Cement Mortar Linings in Cast and Ductile Iron pipes • Industry and literature surveys to identify field failure modes in CML • Quantify the interactions between water quality parameters and CML failure • Develop accelerated test methods for modelling CML degradation • Physical/Probabilistic model to predict failure under different operating conditions and water quality conditions

15. Condition Assessment – Pro-Active assets • Failure models can be calibrated using non-destructive condition assessment techniques • Electromagnetic tools available to measure corrosion pit depth in metallic pipes • Research effort towards the development of condition assessment tools for non-metallics (cement, plastics)

16. Sewer Deterioration Models • Deterioration models developed in EU CARE-S project with 15 partners Models developed for • Structural Collapse • In/Ex Filtration • Blockages • Siltation • Root intrusion

17. More Information • CSIRO - Stewart.Burn@csiro.au • AwwaRf – Jian Zhang • WERF – Roy Ramani • CARE-S - Sveinung Saegrov • http://www.csiro.au • http://www.cmit.csiro.au/research/urbanwater/mouws/