1. Synthèse des travaux du CT Ponts routiers Overzicht van de werkzaamheden van het TC Weggen bruggen
Ir Pierre GILLES
Inspecteur général ff
SPW – DGO1 – Département des Expertises techniques

2. Issues TC Road bridges Issue 4.3.1 - Adaptation to climate change
Identify the technical aspects of road bridges subject to adaptation to climate change taking into consideration the assessment produced by Working Group II: Impacts, Adaption and Vulnerability of the Intergovernmental Panel on Climate Change, IPCC.
Issue – New repair and rehabilitation methods
Examine several degradation problems that can occur on bridges and compare different innovative repair and rehabilitation methods that can be applied to solve these problems. Methods can be innovative by the technique, the way to take traffic into account and/or the reduction of the ecological footprint.

3. Issues TC Road bridges
Issue Risk-based management of the bridge stock
Review how risk management is used in the management of bridge stock.
Investigate the existing tools and identify best practice approach for structures sensitive to each hazard.
Issue Estimation of load carrying capacity of bridges based on damage and deficiency
Analyze existing estimation methods of load carrying capacity of bridges based on damage and deficiency.
Identify best practice approach for the use of data in supporting the estimation of load carrying capacity for reducing damage and deficiency.

4. Reports 4 reports will be available on www.piarc.org Focus on :
Actually only :
Issue – New repair and rehabilitation methods
Issue Estimation of load carrying capacity of bridges based on damage and deficiency
Focus on :
Issue Risk-based management of the bridge stock

5. I. New repair and rehabilitation methods
New rehabilitation methods
Many Bridges
Old + degradation
Less budget

6. New repair and rehabilitation methods
TC – group 2 members imagine 22 real degradation problems
Ask PIARC members for solutions
Compare solutions from different countries
Purpose :
Guidelines for solutions comparaison
Innovation
Technical aspects
Trafic impact
Ecological footprint

7. How to compare rehabilitation solution ?
Base on RAMS
6 parameters
3 cotation levels :
+, +/-, -
Qualitative comparison
Road administration or Contractor

8. Parameters Reliability Availability Maintainability
Technical performance of the method
Comply with specification requirements
Throughout the bridge’s lifetime
Availability
Traffic hindrance impose by the rehabilitation method
Maintainability
Minimal maintenance or monitoring during its service life

9. Parameters Safety Finance Sustainability Safe in execution and use?
Specific safety procedures to be followed during the execution, the inspection and/or the maintenance of the rehabilitation method ?
Finance
Is the method acceptably viable, taking account of both initial and lifecycle costs ?
Sustainability
Impact of this rehabilitation method compared to others on the lifecycle of the bridge?

10. Results 12 countries propose : Conclusion: 59 standard method
48 innovative method
Conclusion:
Preserve the structures instead of replace part of them. Cathodic protection is a good example.
Frequent use in some countries of fibre reinforced polymer (FRP) plates or sheets (+ sometimes post-tensioning).
If partial replacement => new options : lightweight or high performance concrete, or reinforcement with fibres.
Innovation must become more numerious and more ambitious
Quality assessment of the product or the method remains not applied enough
In a large majority of coutries, the rehabilitation method is selected by the road administration

11. II. Risk management embedded in bridge management
Common goal
Ensure the safety and serviceability of bridges at a minimum cost
Implicit or explicit integration in management activities
Design, inclusion of feedback
Evaluation, prioritization, and programming operation and maintenance
Inspection strategy, surveillance and monitoring
Responses to vulnerabilities and hazards
Operating measures, structural assessment, investigations and operation/maintenance

12. Examples of applications in different countries
Belgium-Wallonia
Optimal frequency of detailed inspections with respect to specific hazards or structures
In all cases
Formal or informal risk-based analyses interfering the bridge management system
Sétra - CEREMA methodology (France)
Screen out a large number of structures facing a set of risks to select those in need for further investigation

13. Risk
«A potential hazard or threat, more or less predictable, which may affect the performance of a structure»
A combination of the hazard and the magnitude of consequences
The expected value (cost) of the consequences
May be assessed by three factors
Hazards
Vulnerability
Consequences

14. Hazard Source of risk 4 types : Aging materials Natural phenomena
Initial defects
Phenomena of human origin

15. Vulnerability The sensitivity of a structure to hazards
Depends on the structure and the hazard itself
E.g., a light steel structure is vulnerable to fire, but not earthquakes
Intrinsic with respect to unknown hazards
Ability to resist unknown impact
(Almost) opposite of robustness
Low intensity hazards do not lead to disproportionate consequences

16. Consequences

17. Risk evaluation
Hazard
Vulnerability
Consequence
Criticity
Risk

18. 117 Isostatic precast post-tensioned concrete girder bridges (France)
Insufficient bearing capacity due to corrosion of pre-stressing steel
Hazard criteria
Initial error:
Design;
Initial pre-stressing;
Construction (grounting, tendons quality)
Internal hazards:
Current pre-stressing condition (corrosion) ;
Bridge maintenance (waterproofing replacement) ;
Environment (chlorides) ;
Condition
Three categories of risk : from low (R1) to high (R3) risk

19. 117 Isostatic precast post-tensioned concrete girder bridges (France)
Results
30 out of 117 bridges ranked as R3
All bridges built before 1960 were R3
Actions required for R2 and R3
Modification of surveillance programs
Advanced calculation of structural performance

20. Climate change as a risk
Hazards
Temperature rise, cyclones, rainfall, sea level rise, etc.
Costs of considering these in design vary considerably !
Vulnerability
Parameters related to technical and cultural evolution
Analysis of climate trends, updating regulations and constant monitoring of data
Consequences
Economic impact is huge and largely underestimated
Impossible to estimate a cost on all factors

21. New cycle issues
Issue D.3.1 : Bridge design for inspection and maintenance
Issue D.3.2 : Technical and economic considerations of bridge rehabilitation methods
Issue D.3.3 : Inspections and damage assessment techniques

22. Thank you for your attention