System Engineering & Risk-Informed Management of Civil Infrastructure

Transcription

1 System Engineering & Risk-Informed Management of Civil Infrastructure Martin W. McCann, Jr. Jack R. Benjamin & Associates, Inc. & Stanford University

2 Interesting Times The concept of risk-informed informed management for systems has been around for some time. In some fields within civil engineering, it is practiced more than others. What is new is the present day context: Events of the last years (let alone the last years) have dictated a change, and There is a sense of urgency (costs, public pressure (a reaction to disaster), regulatory oversight, etc.)

3 Previously (Currently.) For the most part, design and safety evaluation of civil infrastructure systems was carried out using a standards-based approach (still in use today) The mindset was we design it to meet the standard; therefore it will perform adequately. Post-construction some systems were largely forgotten (i.e., dam gate systems for instance)

4 Now There is a broader scope (need) to understanding how a system will perform, deciding what is reasonable, appropriate (tolerable). There is an important business case to be addressed regarding the reliable and safe performance of infrastructure systems. At present, there are gaps to be addressed: Toolbox (intellectual, methods, software, etc.), Research needs, and Steps needed to make it a standard of practice

5 My Starting Point - Working Hypothesis The importance of civil infrastructure systems (CI) to our daily lives (quality of life) is more and more important (CI houses the internet, homes, businesses, schools, provides transportation, etc.) Another way to this is; failure of CI has greater impact, even of o course catastrophic impact To varying degrees and at multiple levels, these are all systems Managing CI requires an understanding of risks through their life cycle. By implication, there are a broad range of needs within the profession and within the overall policy making infrastructure to t make this happen.

6 Events Tend to Shape & Re-shape

7 Fukashima NPP (2011)

8 Fort Peck Dam (2011) The USACE has revealed that planned repairs to the Fort Peck Dam in Montana are expected to cost more than $225M, more than four times the amount it has available to spend on the project. Spillway Capacity = 275,000 cfs Max. Release 2011 = 65,000 cfs

9 PG&E San Bruno gas line explosion and fire (Sept. 2010)

10 Hurricane Katrina Lower Ninth Ward (2005)

11 Taum Salk Dam Failure (2005)

12 Folsom Gate Failure (1995)

13 Teton Dam (1976)

14 Buffalo Creek (1972) Location of Three Impoundments

15 Teton Dam Post-Disaster: Findings, Insights, Reflections Design branches in Reclamation in the 60 s and 70 s did not have good communication and did not share information to learn corporate lessons.. Conflicts existed Reclamation-wide between construction offices, geologists and designers. It was a dual failure on the part of the organization... (Snortland, 2009) Hurricane Katrina The System did not perform as a system: the hurricane protection in New Orleans and Southeast Louisiana was a system in name only... (USACE, General Strock) PG&E Gas Explosion Quality (risk) analysis could both facilitate two-way communication between top management and individuals with substantial knowledge e about each of the relevant aspects of utility operations and provide a clear r understanding of all the information available to make a key risk management decision. sion. There is no evidence top management has taken the steps necessary y to be well- informed about the key aspects of decisions selected to manage major m risks that concern PG&E. (Independent Review Panel, San Bruno Gas Explosion)

16 Other Lessons & Motivators A Business and Liability Case for Corporations:.... it is the job of the CEO and senior management to assess and manage the company s s exposure to risk. The audit committee should discuss the company s s major financial risk exposures and the steps management has taken to monitor and control such exposures. NYSE Listing Standards Part 7d

17 Common Contributors to Failure Issues Related to CI Management Focus on Financial Performance Focus on Not System Safety Fixing Symptoms not Problems Complacency, Arrogance, Ignorance Changes in Process or Procedures Poor Communications Focus on Regulatory Requirements (standards) Lack of Corporate Safety Culture Courtesy; Pat Regan (2012) FERC

18 Civil Infrastructures Systems In light of some of the findings of these past events - what do we mean? There are other systems within which the civil infrastructure system is designed, constructed, operated, appropriated, etc.

19 Intellectual Infrastructure The brain trust of professionals that deems a concept, approach, standard of practice acceptable or adequate. This infrastructure fails when the informed technical community is aware and capable of providing insight and guidance that would offer an alternative to the status quo and it goes unnoticed; ignored, etc. A failure to act on the part of management; policy makers (Congress, parliament, etc.)

20 Consider the Following Consider the following relative to the 9/11 Terrorist Attacks: FAA Needs Pre-board Passenger Screening Performance Standards Development of New Security Technology Has Not Met Expectations Aviation Security: Urgent Issues Need to Be Addressed Vulnerabilities Still Exist in the Aviation Security System Reference: Bazerman, M. and M. Watkins Predictable Surprises, Source: Titles of GAO reports written prior to 9/11/2001 written from 1987 to 2000.

21 A Hierarchical System for Managing Critical Infrastructure Risks Action / Change HPS New Orleans Government / Elected Officials X Ceilings Engineering Bureaucracy X Informed Technical Community X

22 Take Away Thoughts Major system failures are not particularly rare. There is a gap that exists in the profession s understanding and management of risks and the management of CI. The broader System (engineering, management, and policy) requires re-thinking.

23 Seismic Safety Evaluation of Dams Background PFMA s performed for projects according the standard practice (FERC, USBR) FERC is moving to risk-informed informed approach to regulation Tolerable risk criterion for public safety Issue How to conduct seismic evaluations of dams Systems approach (multiple system level failure modes) Considerations of uncertainty (aleatory and epistemic) Pragmatic (cost and time efficient)

24 Straightforward Solution All utilities conduct risk analyses for all FERC licensed projects! Doable (in time); not very pragmatic Resource issues Cost (licensee cost) Not very realistic in many cases (e.g., Low Hazard dams) Find a pragmatic alternative; require a risk analysis in special cases

25 Seismic Risk & Tolerability SR = H * SF Seismic Risk = Hazard * Seismic Fragility (Known) (Known) (Unknown) We have one equation and one unknown; we can do the math. In this case, the SR is really a tolerable risk level (an upper-bound), in which case the SF corresponds to a minimum seismic capacity that has to be demonstrated.

26 Seismic Hazard For a Site Tolerable Risk Criterion Site 3 1.E-01 Mean 5th% 16th% 50th% 84th% 95th% Exceedance Frequency. 1.E-02 1.E-03 1.E-04 1.E PGA (g)

27 Seismic Risk & Tolerability Seismic Safety Tolerable Risk Known Seismic Risk for a Facility Seismic Hazard Seismic Fragility Known *

28 Key Features of the Process Evaluating the dam system as a system considering system; structure, component interactions, etc. Uncertainty; ; aleatory and epistemic Assessing the Impact to the Public - Potential Loss of Life Defining, for now, a tolerable risk criterion for the public Risk-Informed Seismic Evaluation of Hydro Projects

29 Viewing the Dam System as a System URR or Hydrologic Seismic Operational Intrinsic or Embankment Fails or Overflow Section Fails or Failure Mode E1 Failure Mode E2 Failure Mode E3 Failure Mode O1 Failure Mode O2 Given an earthquake (ground shaking at the dam site), URR occurs if E1 or E2 or E3 or O1 or O2 occurs.

30 Seismic Fragility A seismic fragility curve defines the chance of failure as a function of ground motion. Conditional Probability of Failure, P(f a) /50 Chance of Failure No Chance of Failure a = 0.3g Ground Motion, a Failure is Certain

31 Seismic Fragility (cont.) For structure failure mode we can determine a seismic fragility curve. Note, some failure modes are weaker/stronger than others. Conditional Probability of Failure, P(f a) E2 E3 O1 E1 O2 Ground Motion, a

32 Seismic Fragility (cont.) Given an earthquake (ground shaking at the dam site), URR occurs if E1, or E2 or E3 or O1 or O2 occurs. The fragility curve tells us for a give structure failure mode what w the chance of URR is simple read it off the curve Conditional Probability of Failure, P(f a) P(E2 a) = E2 a = 0.3g Ground Motion, a

33 Seismic Fragility (cont.) We can repeat this for each failure model. Now we need to estimate the chance the URR occurs due to any failure mode Conditional Probability of Failure, P(f a) 1.0 P(E3 a) = P(E1 a) = 0.20 P(E2 a) = E3 E2 E1 O1 a = 0.3g Ground Motion, a O2

34 Seismic System Level Fragility We consider all failure models and repeat this exercise for all ground motion levels Conditional Probability of Failure, P(f a) P(URR a) ~ 1.0 P(E3 a) = P(E1 a) = 0.20 P(E2 a) = URR Fragility Curve E3 E2 E1 O1 a = 0.3g Ground Motion, a O2

35 Seismic Evaluation Process Figure

36 Seismic Evaluation Process High Level System Model Tolerable Risk Criterion Performance Criteria & Best/Non- Conservative Analysis DONE Yes Public Safety Impact Seismic Methodology Seismic Evaluation GM Seismic Calculations OK? More Detailed Analysis No Estimates of Uncertainty Site-Specific PSHA Options? Seismic Risk Analysis

37 Key Elements of the Seismic Evaluation Seismic-Systems Systems PFMA Workshop Despite the pre-existence existence of a PFMA (per FERC current practice), a focused seismic & systems-based evaluation was required Results multiple, new failure modes identified. Emphasis that best/non-conservative evaluations be conducted Dam-break and inundation estimates Loss-of of-life estimates Seismic engineering estimates Develop a high level systems model Identify system level failure modes Direct consideration of the uncertainty in the seismic hazard and seismic fragility of structures and components

38 ASCE Guidelines for Critical Infrastructure (2009) Hurricane Katrina, the levee failures, and the findings of the USACE own investigation had a profound impact on the agency and the profession. The consequences of the levee failures in New Orleans focused the nation s s and the civil engineering profession s s attention on the root causes of what is considered one of the worst infrastructure disasters in our nation s s history.

39 ASCE Guidelines They established four guiding principles: Quantify, communicate, and manage risk. Employ an integrated systems approach. Exercise sound leadership, management,, and stewardship in decision-making processes. Adapt critical infrastructure in response to dynamic conditions and practice. Nothing that ASCE concluded/recommended was technically infeasible before Katrina!

40 Risk-Informed Elements for the Present A profession, ownership (all levels of management), and as applicable regulators, and policy makers who understand infrastructure risks Risks - business and public safety risks Risk-informed informed business decisions support a business s s viability and public safety Understanding of risks that is systems-based

41 Risk-Informed Elements for the Present All levels of CI management should be guided by an understanding of risks; system performance and consequences Design Inspection Maintenance and operation Replacement CI owners/operators and regulators (as the case might be) should support and contribute to community resilience Engaged, contributing participants Establish sound, clear means to communicate risks and risk management program status to upper management (e.g., OPG maturity matrix approach).

42 Bow-Tie Life-Cycle View of Risk Management Sequences of Events Hazards/Threats Consequences Undesirable Events

43 Life-Cycle View of Infrastructure Management Sequences Leading to Undesirable Events/Consequences Courtesy: Des Hartford

44 Engineering Design Courtesy: Des Hartford

45 Full Risk Management Program Courtesy: Des Hartford

46 Something We Don t t Want!

47 Thank You