Platzhalter für Bild, Bild auf Titelfolie hinter das Logo einsetzen Leichtweiß-Institute for Hydraulic Engineering and Water Resources Department of Hydromechanics and Coastal Engineering Marie Naulin, Andreas Kortenhaus & Hocine Oumeraci | 9 December 2011 | FRMRC Science of Asset Management Workshop | SAM 2011 | London Reliability of linear structures - Latest advances and challenges from a European perspective

9 December 2011 | Naulin et al. | Reliability of linear structures | Page 2 Contents  Motivation  Reliability analysis - Latest advances in XtremRisK project  Introduction  Reliability analysis of sea dikes, coastal dunes & flood defence walls  Time dependency  Further research projects incl. reliability aspects in Europe  Future challenges

9 December 2011 | Naulin et al. | Reliability of linear structures | Page 3 North Sea Flood of 1962, Hamburg, Germany

9 December 2011 | Naulin et al. | Reliability of linear structures | Page 4 Legal Background European Flood Directive (2007/60/EC)  Directive on “the assessment and management of floods”  Required steps of the member states:  Preliminary flood risk assessment (22 Dec 2011)  Flood hazard and flood risk maps (22 Dec 2013)  Flood risk management plans (22 Dec 2015)

9 December 2011 | Naulin et al. | Reliability of linear structures | Page 5 German Joint Research Project “XtremRisK”  Development of methods to perform an integrated risk analysis based on the "Source-Pathway-Receptor - concept “ for open coasts and estuaries exposed to extreme storm surges  Analysis of current (2010) and future (2100) scenarios  Term of project: 2008 – 2012  Partners: three German universities, local authorities & other consulting partners area at risk flood defence structures storm surge Source Pathway Receptor Extreme storm surges Flooding probability Vulnerability assessment (tangible/ intangible) Integration (Risk analysis, risk evaluation and risk management)

9 December 2011 | Naulin et al. | Reliability of linear structures | Page 6 Overview of Subproject 2 (Risk Pathway) Objectives  Analysis of the loading and reliability of coastal flood defence structures under extreme storm surges Methodology  Reliability analysis of flood defences  Breach modelling of dikes and dunes Results  Failure probabilities P f of the flood defence systems  Initial flooding condition due to wave overtopping/ overflow and / or breaching  results will used for inundation modelling of the hinterland and for integrated flood risk analysis

9 December 2011 | Naulin et al. | Reliability of linear structures | Page 7 Input Data by Subproject 1 (Risk Source)  Empirical and statistical analysis of observed water level gauges  Parameterization of storm surges and development of a storm surge generator  Multivariate statistical assessment of the storm surge curves using the parameters ‘highest turning point' and ‘fullness‘  Joint exceedance probability P e Source: Wahl et al. (2010) Definition: „Fullness“

9 December 2011 | Naulin et al. | Reliability of linear structures | Page 8 b) Failure mechanisms and limit state equations (LSE): z = R – S z 0: no failure Reliability Analysis of Flood Defences LSE Wave Overtopping/ Overflow z = q adm - q c) Uncertainties, calculation of failure probabilities a) Description of flood defence system d) Fault tree analysis Dike Mobile flood wall Storm surge barrier Flood wall Wave Overtopping Overflow q q

9 December 2011 | Naulin et al. | Reliability of linear structures | Page 9 Failure Mechanisms of Sea Dike waves and water level at structure overflow overtopping Failure mechanisms at landward slope Velocity wave overtopping Velocity overflow Erosion (grass, clay, sand) Sliding of clay layer Uplift of clay layer Deep slip (Bishop) Breach development geometry and soil parameters of the dike Failure mechanisms in the dike Piping Matrix erosion Sliding LOADING RESISTANCE loading at structure Failure mechanisms at dike top “Kappensturz” Non-structural failure mechanisms Wave overtopping Overflow Failure mechanisms at seaward slope Wave impact Velocity wave run-up Erosion (grass, clay, sand,) Instability revetment Uplift revetment Deep slip (Bishop) Breach development

9 December 2011 | Naulin et al. | Reliability of linear structures | Page 10 Overview of General Fault Tree for Sea Dikes TOP Flooding of Hinterland Dike Breach Failure Seaward Slope Failure Landward Slope Failure Inner Dike LSE Over- topping LSE Overflow Failure Dike Top OR LSE 1 LSE m OR LSE 1 LSE n OR LSE 1 LSE o OR LSE 1 LSE p OR Non- Structural Failure LSE = limit state equation

9 December 2011 | Naulin et al. | Reliability of linear structures | Page 11 Failure Mechanisms of Coastal Dune waves and water level at structure overflow overtopping Failure mechanisms at landward slope Overwash Breach geometry and soil parameters of the dune LOADING RESISTANCE loading at structure Non-structural failure mechanisms Wave overtopping Overflow Failure mechanisms at seaward slope Erosion

9 December 2011 | Naulin et al. | Reliability of linear structures | Page 12 Overview of General Fault Tree for Coastal Dune TOP Flooding of Hinterland LSE Overwash LSE Breach LSE Over- topping LSE Overflow OR Non- Structural Failure Structural Failure LSE developed for dikes LSE Erosion LSE = limit state equation

9 December 2011 | Naulin et al. | Reliability of linear structures | Page 13 Overview of General Fault Tree for Flood Defence System River Estuary flood defence system with flood threat from sea and river (e.g. estuary) Dike Flood wall Lock Protected area Dune River dike (levee) Sea TOP Flooding of Hinterland OR River dike Lock Dune Flood wall OR Dike section 1 Dike section n * * * * Dike Breach Non- Structural Failure * OR * *

9 December 2011 | Naulin et al. | Reliability of linear structures | Page 14 Time Dependency detoriation Legend

9 December 2011 | Naulin et al. | Reliability of linear structures | Page 15 Adjustments of Limit State Equations Example: LSE for wave overtopping and overflow LSE compares overtopping/overflow rates of flood defence structure: Where: q adm = admissible overtopping rate [m³/s/m] q = actual overtopping rate [m³/s/m] mean overtopping/ overflow rate total overtopping/ overflow volume q q Adjustment LSE compares total overtopping/overflow volumes of flood defence system: Where: V adm = admissible overtopping/overflow volume [m³] V = actual overtopping/overflow volume [m³] z = q adm – q z = V adm – V

9 December 2011 | Naulin et al. | Reliability of linear structures | Page 16 Research Projects incl. Reliability Aspects at TU Braunschweig Recent: FLOODsite (EU) Integrated Flood Risk Analysis and Management Methodologies Ongoing: XtremRisK Extreme storm surges at open coasts and estuarine areas - Risk assessment and mitigation under climate change aspects NTH BAU – SP4 A risk-based strategy for monitoring, inspection and maintenance of coastal protection structures as an integral part of life cycle calculation and optimization processes COMTESS Sustainable coastal land management – trade-offs in ecosystem services ProMoHa Implementation of probabilistic calculation of estuary sea dikes in Hamburg, Germany Falster Dike Implementation of probabilistic calculation of sea dikes and coastal dunes in Falster, Denmark

9 December 2011 | Naulin et al. | Reliability of linear structures | Page 17 Selection Research Projects incl. Reliability Aspects in Europe Recent: ComCoast (EU), FLOODsite (EU), SafeCoast (EU), RIMAX (DE) Ongoing: BaltCICA Climate Change: Impacts, Costs and Adaptation in the Baltic Sea Region (EU) CRITERRE Application of geophysics to levee assessment and ERINOH National research project on internal erosion (FR) FloodControl2015 / SBW Solutions for smart flood control (NL) FloodProBE – WP3 Reliability of urban flood defences (EU) FRMRC Flood risk management research consortium (UK) HoRisK Flood risk management for coastal areas (DE) LDA / TOI Levee Design and Assessment (NL) THESEUS Innovative technologies for safer European coasts in a changing climate (EU)

9 December 2011 | Naulin et al. | Reliability of linear structures | Page 18 Some Future Challenges  Mean sea level rise  Increased storminess  Transitions  Length effects  Time dependence  Flood defence systems  Single point structures  Human and organisation errors (HOE) ... Time dependence Transitions Mean sea level rise HOE FloodControl 2015 Church & White (2006)

9 December 2011 | Naulin et al. | Reliability of linear structures | Page 19 Contact Marie Naulin Leichtweiß-Institute for Hydraulic Engineering and Water Resources Department of Hydromechanics and Coastal Engineering TU Braunschweig T: F: E: trem R isK X Thank you for your attention!