1. LoBEG’s New Prioritisation Approach for Highway Structures
Richard McFarlane
Royal Borough of Kingston Upon Thames
Road Conference – 21st November 2011

2. Road 2011 Conference – 21st November 2011
Summary
Background
Value for Money Definition
Prioritisation Approach Overview
Stages in the Prioritisation Approach
Optimisation: Achieving Value for Money
Summary of Progress to Date
Concluding Remarks
Road Conference – 21st November 2011

3. Road 2011 Conference – 21st November 2011
Background
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4. Road 2011 Conference – 21st November 2011
LoBEG’s Vision
The Asset Management Planning Process describes what is required to support the effective management of highway structures.
Work has progressed, developing each off the component parts and enhancing BridgeStation.
Over the years LoBEG has overseen the gradual evolution of its prioritisation processes
All sub-processes of the Asset Management Planning Process were developed by the LoBEG Asset Management Working Group.
Road Conference – 21st November 2011

5. Prioritisation Process Evolution
1998/1999
Strengthening Prioritisation process for highway structures
used for the fair and objective allocation of bridge strengthening capital funds between London Boroughs.
2000
Revision made to the strengthening prioritisation system to include capital maintenance
It was not trialled or used
2009
Good Practice Guide on Element Level Prioritisation
used to prioritise needs at element level (based on condition data)
identification of potential maintenance schemes
2010/11
Developing a Good Practice Guide on the Objective Prioritisation of Planned Maintenance Work
all needs are rigorously assessed
limited capital resources optimally allocated
Road Conference – 21st November 2011

6. Latest Prioritisation Process Objectives
Develop an end-to-end process that is suitable for all highway authorities in London, i.e. boroughs and TfL;
Develop a process that is objective and fair;
Support the allocation of limited resources in a manner that provides best value for money, i.e. maximise benefits for the money spent;
Align the process with strategic objectives;
Take account of Whole Life Costs/Value;
Provide a process for rigorously challenging needs and identifying the best solutions;
Achieve Value for Money in the Enhancement and Safeguarding of Highway Structures
Road Conference – 21st November 2011

7. Road 2011 Conference – 21st November 2011
A Definition
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8. Road 2011 Conference – 21st November 2011
The 3 E’s
Value for Money (VfM) is about achieving the maximum benefits possible with the resources and constraints available
Economy – Doing more with fewer resources; Make savings
Efficiency – Doing things the right way
Effectively – Doing the right things at the right time
Road Conference – 21st November 2011

9. Prioritisation Process Overview
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10. Proposed Risk Based Approach
Road Conference – 21st November 2011

11. Draft Good Practice Guide
The details were extensively considered by the LoBEG Asset Management Working Group
The process is comprehensively described in the associated Good Practice Guide.
The intention is to develop a specific module in BridgeStation to support the effective implementation of this process.
Road 2011 Conference – 21st November 2011

12. Road 2011 Conference – 21st November 2011
Risk Evaluation
Risk = f ( Likelihood, Consequence)
Likelihood = f ( Defect being assessed)
Score on 1 to 100 scale
Consequence = f ( Structure characteristics)
Risk Score on 1 to 100 scale
Road Conference – 21st November 2011

13. Road 2011 Conference – 21st November 2011
Value Criteria
Value Criteria
Definitions
Aspects Covered
Safety
To ensure structural safety without compromising public safety
Deterioration, Loading capacity, other damage
Functionality
Provision of agreed operational requirements
Restrictions imposed
Environment
To minimise environmental impact
Impacts - traffic, watercourses, noise, dust, waste, habitats, heritage structures and appearance of structures
Financial
VfM in terms of overall Risk mitigation, WLC and Constraints
Road Conference – 21st November 2011

14. A 5- Stage Prioritisation Process1
Compile Data 2
Identify Needs 3
Identify Schemes 4
Develop and Evaluate Scheme Options 5
Optimise Programme
Road Conference – 21st November 2011

15. Prioritisation Process
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16. A 5- Stage Prioritisation Process1
Compile Data 2
Identify Needs 3
Identify Schemes 4
Develop and Evaluate Scheme Options 5
Optimise Programme
Road Conference – 21st November 2011

17. Road 2011 Conference – 21st November 2011
Stage 1 – Compile Data
Data Type
Examples
Structure Details & Inventory
structure type, features, dimensions, elements, etc.
Condition
severity and extent to the latest inspection
Substandard Structures
structural capacity, interim measures
Substandard Parapets
containment capacity, road alignment
‘At Risk’ Supports
Scour Risk Data
scour defects records, foundation type
Flood Risk Data
flood likelihood, flood resilience and/or resistance
Lifecycle Plans -
Local Factors
major events, customer complaints, etc.
Road Conference – 21st November 2011

18. Structure Details & Inventory
Must be compliant with the LoBEG Good Practice Guide for Creating Consistent Element Inventories.
Road Conference – 21st November 2011

19. A 5- Stage Prioritisation Process1
Compile Data 2
Identify Needs 3
Identify Schemes 4
Develop and Evaluate Scheme Options 5
Optimise Programme
Road Conference – 21st November 2011

20. Calculate Element/Structure Risk Rating Benchmark
Stage 2 – Identify Needs
Calculate Element/Structure Risk Rating Benchmark
Calculate Likelihood Score
Calculate Consequence Score
‘Needs’ means the needs that arise from condition related as well as other defect types, e.g.
inadequate structural capacity
inadequate containment capacity of supports or parapets
scour defects, etc.
Road Conference – 21st November 2011

21. Stage 2 – Indentify Needs
Condition Likelihood Score, LS-CON
LS-CON=f(Element Current Condition)
Numerical Element Condition
(ECS)
Condition Likelihood Score (LS-CON) = [ x ECS x (ECS + 6.5)]
Section in the Good Practice Guide
Road Conference – 21st November 2011

22. Road 2011 Conference – 21st November 2011
Stage 2 – Indentify Needs Substandard Structures Likelihood Score, LS-SUBSTR
LS-SUBSTR=f(Assessed Capacity, Vehicular Traffic Volume)
Section in the Good Practice Guide
Road Conference – 21st November 2011

23. Stage 2 – Indentify Needs Consequences Score Evaluation
Impact
Safety
Functionality
Environment
Consistent and Practical Inventories for Highway Structures
LoBEG is preparing a Good Practice Guide for publication in the next few months to provide guidance on an approach for creating consistent and practical element inventories for highway structures.
There is variability in how element inventories are created. Consistency is vital to recent and forthcoming bridge management techniques, e.g. calculating the Bridge Condition Indicators, prioritising maintenance, valuing/depreciating assets, lifecycle planning, long-term financial planning and comparing authorities. To ensure these approaches are suitably supported, it is essential that element breakdowns are done in a consistent manner, especially as authorities look to define more detailed element inventories above and beyond the Bridge Inspection Reporting guidance.
Road Conference – 21st November 2011

24. Stage 2 – Identify Needs Risk Evaluation
For each element
Calculate Ls (likelihood score) for each defect
Calculate Cs (consequence score) for each VC (Value Criterion)
Combine Ls and Cs on the risk matrix to determine a Safety (SRS), Functionality (FRS) and Environment (ERS) Risk scores
Section in the Good Practice Guide
Road Conference – 21st November 2011

25. Stage 2 – Identify Needs Risk Evaluation (continued)
The Risk Scores obtained from the preceding matrix for each of the Value Criteria are combined and weighted using the following equation to determined the Risk Rating Benchmark (RRB) for an element/structure.
RRB = 0.5 x SRS x FRS x ERS
Section in the Good Practice Guide
Road Conference – 21st November 2011

26. Stage 2 – Identify Needs Risk Rating Benchmark Classification
Classify Element/Structure Risk Rating Benchmark
Section in the Good Practice Guide
Road Conference – 21st November 2011

27. A 5- Stage Prioritisation Process1
Compile Data 2
Identify Needs 3
Identify Schemes 4
Develop and Evaluate Scheme Options 5
Optimise Programme
Road Conference – 21st November 2011

28. Stage 3 – Identify Schemes
Develop Element/Structure Priority List and Apply Cut-offs
Condition
Substandard Structures
Substandard Structures with interim measures
‘At Risk’ Supports
Substandard Parapets
Flood Risk
Scour Risk
Local Factors
Road Conference – 21st November 2011

29. Stage 3 – Identify Schemes Presentation by Structure
Road Conference – 21st November 2011

30. A 5- Stage Prioritisation Process1
Compile Data 2
Identify Needs 3
Identify Schemes 4
Develop and Evaluate Scheme Options 5
Optimise Programme
Road Conference – 21st November 2011

31. Stage 4 – Develop and Evaluate Scheme Options
Calculate Scheme Total Risk Rating Benchmark
Sum Elements’ Risk Rating Benchmarks
Calculate Scheme / Option Risk Mitigation
Evaluate Residual Risks
Evaluate Total Residual Risk
Road Conference – 21st November 2011

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Stage 4 – Develop and Evaluate Scheme Options Proposed Risk Mitigation Evaluation
If resources are to be expended, wouldn't you like to know what impact this would have on your level of Risk?
Calculate the Risk Rating Benchmark (RRB) for each element
Calculate Residual Risk (RR) for each proposed maintenance activity = RRB x Control Factor
Calculate the Total Residual Risk (TRR) for each proposed maintenance scheme = ∑RR
Calculate total Risk Rating Benchmark (TRRB) for each scheme = ∑RRB
Calculate the scheme’s Risk Mitigation:
Total Risk Rating Benchmark – Total Residual Risk
x 100 %
Total Risk Rating Benchmark
Road Conference – 21st November 2011

33. Stage 4 – Develop and Evaluate Scheme Options Control Factors
Description of Risk Mitigation / Control Measure 1
No action will be taken, no risk mitigation / control measure will be applied, i.e. the element/component/structure will remain in an 'As-Is' state
0.6
Action or other mitigation / control measure will be taken but this would only reduce the risk by 25%, i.e. monitoring, structure closure, etc., will be employed as appropriate
0.4
Action or other mitigation / control measure will be taken but this would only reduce the risk by 50%, i.e. minor to moderate maintenance work will be employed as appropriate at discreet locations, e.g. minor to moderate concrete repair, mortar re-pointing, strapping, surface treatment, etc.
0.2
Action or other mitigation / control measure will be taken but this would only reduce the risk by 75%, e.g. minor maintenance work, lane / weight / speed restrictions, temporary structure, propping, etc. will be employed as appropriate
Suitable action will be taken, the mitigation / control measure will eliminate or fully mitigate the risk, i.e. the element/component/structure will be fully reinstated in a 'as good as new' state; e.g. maintenance work, component renewal/replacement, strengthening and/or permanent measures, etc. will be employed as appropriate
Road Conference – 21st November 2011

34. A 5- Stage Prioritisation Process1
Compile Data 2
Identify Needs 3
Identify Schemes 4
Develop and Evaluate Scheme Options 5
Optimise Programme
Road Conference – 21st November 2011

35. Stage 5 – Optimise Programme
Switch on/off Constraints & Objectives
Define Constraints
Define Objectives
Road Conference – 21st November 2011

36. Optimisation… in our context
We have a penny or two to spend
We have no budget constraints
We have evaluated the Total Risk Rating Benchmark (TRRB) for each structure/scheme
We can rank structures/schemes; those with the highest TRRB appear first
We can use a simple prioritised list to allocate funding
It would simply be a case of what to do first and what to do last
Surely there is nothing wrong with that, right?
But our world is not so simple…
Road Conference – 21st November 2011

37. Stage 5 – Scheme Optimisation Define Objectives & Constraints
The Excel Solver tool helps answer optimisation problems
Type
Description
Objective
Maximise Risk Mitigation
Constraint 1
The specified budget must not be exceeded
Constraint 2
Only options that have a positive financial indicator may be selected
Constraint 3
If Constraint 2 cannot be met then the 'Do Minimum' option must be selected
Constraint 4
A maximum of one option per scheme must be selected
Road Conference – 21st November 2011

38. Summary of Progress to Date
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39. Summary of Progress to Date
The draft prioritisation process has been developed
A proof-of concept model was produced and is currently used to test the prioritisation process using real data associated with a number schemes
The testing will be completed at the end of November with the associated documentation being released for wider use at that time
The module will be coded into BridgeStation and it is anticipated that this will be available for use in early FY 12/13.
Road Conference – 21st November 2011

40. Road 2011 Conference – 21st November 2011
Concluding Remarks
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41. Road 2011 Conference – 21st November 2011
Conclusions
Current Environment & Challenges:
Limited maintenance budgets
Increasing financial scrutiny
Decreasing staffing or available resources
The Solution:
A robust and fair mechanism of identifying and prioritising all maintenance needs
Demonstration of achieving value for money through the optimal allocation of funds/resources
Work smarter
Road Conference – 21st November 2011

42. Road 2011 Conference – 21st November 2011
Thank You
Road Conference – 21st November 2011