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Reliability of linear structures - Latest advances and challenges from a European perspective . Marie Naulin, Andreas Kortenhaus & Hocine Oumeraci | 9 December 2011 | FRMRC Science of Asset Management Workshop | SAM 2011 | London . Contents. Motivation - PowerPoint PPT Presentation
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Platzhalter für Bild, Bild auf Titelfolie hinter das Logo einsetzen
Leichtweiß-Institute for Hydraulic Engineering and Water ResourcesDepartment 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 structuresstorm 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 Pf 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 Pe
Source: Wahl et al. (2010)
Time
Sea level
S
f(x)
2
1
t
t
dxf(x)F
t1 t2
NN
Definition: „Fullness“
9 December 2011 | Naulin et al. | Reliability of linear structures | Page 8
b) Failure mechanisms and limit state equations (LSE): z = R – Sz < 0: failure, z > 0: no failure
Reliability Analysis of Flood Defences
LSE Wave Overtopping/Overflow z = qadm - q
c) Uncertainties, calculation of failure probabilities
a) Description of flood defence system
d) Fault tree analysis
Dike Mobile flood wall
Storm surge barrierFlood wall
Wave Overtopping
Overflow
q
q
9 December 2011 | Naulin et al. | Reliability of linear structures | Page 9
Failure Mechanisms of Sea Dike
waves andwater levelat structure
overflowovertopping
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
developmentgeometry and soil parameters of the dike
Failure mechanismsin the dike• Piping• Matrix erosion• Sliding
LOADING
RESISTANCE
loading at structure
Failure mechanismsat dike top• “Kappensturz”
Non-structuralfailure mechanisms• Wave overtopping• Overflow
Failure mechanismsat 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 DikeLSE Over-
toppingLSE
Overflow
Failure Dike Top
OR
OR
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 andwater levelat structure
overflowovertopping
Failure mechanisms at landward slope• Overwash• Breach
geometry and soil parameters of the dune
LOADING
RESISTANCE
loading at structure
Non-structuralfailure mechanisms• Wave overtopping• Overflow
Failure mechanismsat 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
OROR
Non-Structural
FailureStructural
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 SystemR
iver
Estuary
flood defence system with flood threat from sea and river (e.g. estuary)
Dike
Flood wall
Lock
Protected area
Dune
Riv
er d
ike
(leve
e)
Sea
Sea
TOP Flooding of Hinterland
OR
River dike Lock Dune Flood
wall
OR
Dikesection 1
Dike
Dikesection n
* * * *
Dike Breach
Non-Structural
Failure
*OR
* *
9 December 2011 | Naulin et al. | Reliability of linear structures | Page 14
Time Dependency
detoriation
detoriation
Legend
9 December 2011 | Naulin et al. | Reliability of linear structures | Page 15
Adjustments of Limit State EquationsExample: LSE for wave overtopping and overflowLSE compares overtopping/overflow rates of flood defence structure:
Where:qadm = admissible overtopping rate [m³/s/m]q = actual overtopping rate [m³/s/m] mean overtopping/ overflow rate
total overtopping/ overflow volume
q
q
V(t)
AdjustmentLSE compares total overtopping/overflow volumes of flood defence system:
Where:Vadm = admissible overtopping/overflow volume [m³]V = actual overtopping/overflow volume [m³]
z = qadm – q
z = Vadm – V
9 December 2011 | Naulin et al. | Reliability of linear structures | Page 16
Research Projects incl. Reliability Aspects at TU BraunschweigRecent:
• 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
• ProMoHaImplementation of probabilistic calculation of estuary sea dikes in Hamburg, Germany
• Falster DikeImplementation 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 EuropeRecent:
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
TransitionsMean sea level rise
HOE
FloodControl 2015
Church & White (2006)
9 December 2011 | Naulin et al. | Reliability of linear structures | Page 19
ContactMarie Naulin
Leichtweiß-Institute for Hydraulic Engineering and Water ResourcesDepartment of Hydromechanics and Coastal Engineering
TU BraunschweigT: +49 531 391-3937F: +49 531 391-8217
tremRisKXwww.xtremrisk.de
Thank you for your attention!