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

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 4.3.2 – 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.

Issues TC Road bridges Issue 4.3.3 - 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 4.3.4 - 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.

Reports 4 reports will be available on www.piarc.org Focus on : Actually only : Issue 4.3.2 – New repair and rehabilitation methods Issue 4.3.4 - Estimation of load carrying capacity of bridges based on damage and deficiency Focus on : Issue 4.3.3 - Risk-based management of the bridge stock

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

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

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

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

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?

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

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

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

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

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

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

Consequences

Risk evaluation Hazard Vulnerability Consequence Criticity Risk

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

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

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

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

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