Embankment Dam and Spillway Relative Risk Procedures (for Asset Management/Maintenance)

1. Embankment Dam and Spillway Relative Risk Procedures (for Asset Management/Maintenance) Luc Chouinard – McGill University

2. Asset Management Project Context • Improve procedures for evaluating the current state of assets • Inspections performed on an annual basis and reports filed with government agencies • Develop objective procedures for ranking maintenance priorities • Limited budgets • Ranking process must be uniform across all administrative units USACE WORKSHOP 2006

3. Asset Management Project Objectives • Asset Management Strategy for: • Embankment dams • Spillways • Concrete dams USACE WORKSHOP 2006

4. Asset Management General principles Identification and ranking of maintenance interventions. • Current state is determined from site inspection and data from dam/spillway performance evaluation reports (~component reliability – REMR scale) • Importance is based on the contribution of various components to dam/spillway performance (~for system reliability), specific for each facility. • Ranking is established as a function of relative importance and current state of dam components USACE WORKSHOP 2006

5. Asset Management for Embankment Dams • Initiated in 1995 (Hydro-Quebec with USACE) • Tested by Hydro-Quebec in 1999 on 25 dams • Application Guide developed in 2000 by Hydro-Quebec (reduce uncertainty) • Gradually introduced in all districts • Adopted by Manitoba-Hydro and Cemagref (France) USACE WORKSHOP 2006

6. Asset Management Methodology Failure Modes A Evaluation of Relative Probabilities Adverse Conditions Adverse Condition Indicators B Importance Evaluation Defense Groups Monitoring Activities and Devices C Condition Evaluation Condition of Monitoring Activities and Devices Condition of Defense Groups D Priority ranking Monitoring Activities Priorization Monitoring Devices Maintenance Defense Group Maintenance USACE WORKSHOP 2006

7. Asset Management USACE WORKSHOP 2006

8. Asset Management USACE WORKSHOP 2006

9. Asset Management ADVERSE CONDITIONS AND FAILURE MODES USACE WORKSHOP 2006

10. Asset Management USACE WORKSHOP 2006

11. Asset Management Failure Modes (4) A Evaluation of relative probabilities A RULES Adverse Conditions AC1 to AC7 TABLE 2.8 Adverse Condition Indicators Defense Groups DG1 to DG8 B Importance Evaluation Monitoring Activities and Devices C Condition Evaluation Relationship to set up Condition of Monitoring Activities and Devices Condition of Defense Groups D Priority ranking Monitoring Activities Priorization Monitoring Devices Maintenance Defense Group Maintenance USACE WORKSHOP 2006

12. Asset Management USACE WORKSHOP 2006

13. Asset Management Failure Modes (4) A Evaluation of relative probabilities A RULES Adverse Conditions AC1 to AC7 TABLE 2.8 Adverse Condition Indicators Defense Groups DG1 to DG8 B Importance Evaluation Monitoring Activities and Devices TABLES 2.12 to 2.19 C Condition Evaluation Relationship to set up Condition of Monitoring Activities and Devices Condition of Defense Groups D Priority ranking Monitoring Activities Priorization Monitoring Devices Maintenance Defense Group Maintenance USACE WORKSHOP 2006

14. Asset Management REMR Scale USACE WORKSHOP 2006

15. Asset Management • Condition Table for a Defense Group • Define its function (performance based) • Define what is an excellent condition (100) • Define what is a failed condition (0) • Identify indicators of condition • Physical measurement • Performance level • Qualitative observation USACE WORKSHOP 2006

16. Asset Management USACE WORKSHOP 2006

17. Asset Management USACE WORKSHOP 2006

18. Asset Management USACE WORKSHOP 2006

19. Pressure control in foundation Asset Management Upstream slope protection USACE WORKSHOP 2006

20. Asset Management USACE WORKSHOP 2006

21. Asset Management Failure Modes (4) OBSERVATION QUALITY DATA INTERPRETATION ASubjective Evaluationof Risk B RULES A RULES Adverse Conditions AC1 to AC7 TABLE 3.2 TABLE 2.8 Adverse Condition Indicators AC IND1 to IND12 Defense Groups DG1 to DG8 B Importance Evaluation Monitoring Activities and Devices TABLES 2.12 to 2.19 C Condition Evaluation Relationship to set up Condition of Monitoring Activities and Devices Condition of Defense Groups TABLE 2.20 D Priority ranking Monitoring Activities Priorization Monitoring Devices Maintenance Defense Group Maintenance USACE WORKSHOP 2006

22. Asset Management Deformation Seepage Pressure Vegetation USACE WORKSHOP 2006

23. Asset Management Failure Modes (4) OBSERVATION QUALITY DATA INTERPRETATION ASubjective Evaluationof Risk B RULES A RULES Adverse Conditions AC1 to AC7 TABLE 3.2 TABLE 2.8 Adverse Condition Indicators AC IND1 to IND12 Defense Groups DG1 to DG8 B Importance Evaluation C RULES TABLE 3.4 Monitoring Activities and Devices MD1 to MD14 TABLES 2.12 to 2.19 TABLE 3.5 C Condition Evaluation Relationship to set up Condition of Monitoring Activities and Devices Condition of Defense Groups TABLE 2.20 D Priority ranking Monitoring Activities Priorization Monitoring Devices Maintenance Defense Group Maintenance USACE WORKSHOP 2006

24. Asset Management Failure Modes (4) OBSERVATION QUALITY DATA INTERPRETATION ASubjective Evaluationof Risk B RULES A RULES Adverse Conditions AC1 to AC7 TABLE 3.2 TABLE 2.8 Adverse Condition Indicators AC IND1 to IND12 Defense Groups DG1 to DG8 B Importance Evaluation C RULES TABLE 3.4 Monitoring Activities and Devices MD1 to MD14 TABLES 2.12 to 2.19 TABLE 3.5 C Condition Evaluation Relationship to set up Condition of Monitoring Activities and Devices Condition of Defense Groups TABLE 3.6 TABLE 2.20 D Priority ranking Monitoring Activities Priorization Monitoring Devices Maintenance Defense Group Maintenance USACE WORKSHOP 2006

25. Asset Management Proposed new instruments Visual inspections USACE WORKSHOP 2006

26. Asset Management Spillways USACE WORKSHOP 2006

27. Asset Management Partners • U.S. Army Corps of Engineers • Manitoba Hydro • Ontario Power Generation • U.S. Bureau of Reclamation • Hydro-Québec • McGill University USACE WORKSHOP 2006

28. Asset Management Importance Factors • Conceptual model of the spillway (number of gates, lifting devices, etc.) • Identify major functional issues associated with the spillway • Relative importance of components for each function (factors considered: role of the component,response time, reaction,…) USACE WORKSHOP 2006

29. Asset Management USACE WORKSHOP 2006

30. Asset Management USACE WORKSHOP 2006

31. Functional issues Definition Prevent overtopping during a design Ability to operate all gates to achieve full flood spilling capacity. Prevent overtopping during load Ability to spill the powerhouse flow during load rejection rejection Prevent an unintentional opening of Structural failure of a gate (blowout) or the gates unintended opening of gate due to inaccurate information or a failure of automatic controls. Prevent failure to close a gate Failure to close a gate due to equipment failure or failure to recognize the need to close a gate due to inaccurate information Drawdown the reservoir Ability to drawdown the reservoir to prevent a structural failure of the dam or foundation. Asset Management Step 2 For navigation, recreation, water supply,etc. Control water levels USACE WORKSHOP 2006

32. Asset Management Spillway USACE WORKSHOP 2006

33. Asset Management Spillway USACE WORKSHOP 2006

34. Asset Management Évacuateur USACE WORKSHOP 2006

35. Asset Management Spillway USACE WORKSHOP 2006

36. Asset Management Colloque Maintenance 2000

37. Asset Management USACE WORKSHOP 2006

38. Asset Management Conclusions • Priority ranking identifies most advantageous maintenance activities in terms of dam safety • Method permits good overview of dam condition and behavior • Values Dam Safety Engineer technical judgment • Uniform procedure • Flexible and adaptable USACE WORKSHOP 2006

39. Asset Management Thank you! USACE WORKSHOP 2006