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Intervenant - date
Institut français des sciences et technologies des transports, de l’aménagement et des réseaux
SHM trends and opportunities for civil engineering EWSHM2014
Nantes, July 11, 2014
Frédéric Bourquin, Director, COSYS department,
Bruno Godart, Deputy head, MAST department …
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The vast Field of Civil Engineering
• A vital sector for the Economy (Mobility of human and goods, Water ressources and treatment, Protection against various natural Hazards, Urban development,…)
• A strategic sector for the Energy (e.g. nuclear power plants, off-shore platforms, NGL reservoirs,…)
• A strategic sector for the Army Infrastructures…
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Structures exposed to various actions
• Constantly exposed to aggressive environments (deicing salts, sea water, frost, sulfatic soils, acid water, etc.)
• Exposed to the aging of their equipements and their constitutive materials
• Exposed to the deteriorations of their elements due to increasing utilization (traffic and loads, abrasion, …) and human actions (fires, vehicules impacts, vandalism, explosions,…)
Impact of heavy truck
on the pier
of A11 bridge,
June 1997
Mathilde Bridge fire,
Rouen, Oct 2012
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Water-borne disasters
Scour consequences Pile failures due to torrential flood
Inundation
and
submersion
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Network operation disruption
Landslides
Floods
Structural
failures
(Minnesota,
I-35W - 2007)
Earthquakes
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Networks and cities
Road Congestion (France) City Pollution (China)
Train
derailment
(Spain)
Failure
of water PC
pipe (USA)
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Some challenges for monitoring…
• A Safety priority: some structures are subjected to severe disorders and even collapses…
• A societal demand for more and more availability of the infrastructures (zero interruption !...)
• A heavy and costly investment for the society, that is not easy to replace
• A long lasting patrimony requiring a management policy : thorough inventory, inspection, repair, strengthening, adaptation to new needs,…
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Some challenges for monitoring…
• Appropriate procedures and methods to ensure
– The ultimate load capacity of structures
– The Serviceability
– The Durability and Reliability
– The Availability
• Structural Health Monitoring (SHM) is a key Issue for the management of CE Structures
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The SHM: Main Objectives of surveillance
• The surveillance of structures by Monitoring may have several objectives : – confirm or check the conclusions of a diagnosis
– detect malfunctions
– have a better understanding of the behaviour of a structure
– anticipate its natural ageing
– optimize the maintenance actions
– prevent failures or collapse.
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The SHM: 4 Different levels of surveillance
• There is a progressivity in the SHM which is adapted to each individual structure and to the problem to be treated and which is depending on the available means:
• The Intermittent survey: it is intended to collect at each point of measurement the studied parameters via the intervention of an operator on site (Measurement of distance between studs, fissurometer,… - frequency 1/week or 1/month): – For relatively low speed of deterioration
– Low cost and very little maintenance
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The intermittent survey
Distancemeter with
invar wire 3D Fissurometer (Saugnac type)
Crack
measurement
with a
translucent
fissurometer
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The SHM: 4 Different levels of surveillance
• The temporary surveillance: installation of an instrumentation with automatic data acquisition for a rather short period (several weeks):
– Temporary survey of a structure to confirm a diagnosis (measurements of the activity of cracks,…
– Monitoring of the structure during works made in its vicinity (stability, settlements,…)
– Investigations for a diagnosis (monitoring of the sag under loading, study of the fatigue, vibration analysis,…)
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Temporary surveillance
Gauge J1
Day of measure Stress range (Mpa)
Example of the Cheviré Bridge:
Fatigue histogram on 18 days
Gauges
glued on
steel
Raw measures under traffic
Number
of
cycles
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The SHM: 4 Different levels of surveillance
• The intensified surveillance: to follow closely the evolution of a defective or a doubtful structure, during a rather long period of time (more than one year)
– most often to detect an abnormal evolution
– for better identifying the causes of the disorders and better understanding its behaviour,
– to check the effectiveness of a repair
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Intensified surveillance
Tancarville Bridge (France)
0
5
10
15
20
25
30
35
40
8 9 10 11 12 1 2 3 4 5 6 7 8 9 10 11 12 1 2 3 4 5 6 7 8 9 10 11 12 1 2 3
1995 1996 1997 1998
Cum
ula
tive
num
bre
of f
ailu
res
Upstream suspension
Downstream suspension
Evolution of the number of wire failures recorded during the acoustic
monitoring of the cables of the Tancarville suspension bridge by
LCPC, from august 1995 to march 1998.
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Intensified surveillance
The case of the Cheviré bridge (1988 – 1991) ; Length = 1563 m
The main span consists of a steel orthotropic box girder (L = 162 m)
resting on two prestressed concrete cantilevers (each length 40 m).
Each cantilever is having a high deflection due to creep…
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Intensified surveillance
Evolution of the deflection at the end of the cantilever (in cm)
Difficulty to model the creep…. Is there an asymptote ?
-30
-25
-20
-15
-10
-5
0
1990 1993 1995 1998 2001 2004 2006 2009 2012
Def
lect
ion
(cm
)
Time
BPEL E= 36 GPa
Eurocode 2
E = 26 GPa
Eurocode 2
E = 26 GPa + LCPC
Creep tests on cores
times 1.7
Measures with
inclinometers
?
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Intensified surveillance
The case of the Salanfe dam -
Length 617 m – Height 52 m
A gravity dam damaged by alkali-
aggregate reaction
Irreversible upstream movement has
currently reached 35 mm
at crest level
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Intensified surveillance
Necessity to have a FEM model fitted to the measurements
(displacements and pendulum) to assess the condition of the dam and
then used to model the effects of several sawings in the upper part.
-50
-45
-40
-35
-30
-25
-20
-15
-10
-5
0
0 20 40 60 80
Do
wn
str
eam
d
isp
. (m
m)
Time (years)
Block 23 (set 1)Block 13 (set 1)Block 23 (monitor)Block 13 (monitor)Block 23 (set 3)Block 13 (set 3)Block 23 (set 2)Block 13 (set 2)
Displacement of the crest (measures and model)
Model of a cut
Direct pendulum
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The SHM: 4 Different levels of surveillance
• The safety surveillance: consists in following the evolution of one or more physical variables, preferably measurable, and in applying previously defined safety instructions as soon as these physical variables reach a threshold allowing to characterize a dangerous situation. It necessitates: – a thorough analysis of the phenomena likely to occur and
allowing a reasonable evaluation of the corresponding risks (risk analysis) ;
– an establishment of precise instructions that must be strictly applied when required. For bridges, this set of instructions must include the instructions for the management of the traffic when the thresholds are exceeded.
• It is applied for a short duration, the time to design and implement a repair solution...
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Safety surveillance
Variation of the opening of a flexure crack in a PC bridge deck
as a function of the thermal gradient
Alarm curve
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SHM: the Monitoring of new Structures
• Often applied on strategical structures (Dams, Nuclear Power Plants, Large Bridges,…)
Rion-Antirion bridge (Greece)
Design Loads:
-- Earthquake with a return period of 2000 yrs or 5% possibility of exceedance in 120 yrs
-- Techtonic movements up to 2 m between adjacent mains pylons
-- Wind speeds ut to 260 km/h and Ship collision of 180000t DWT
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SHM: the continuous Monitoring of Structures
• Monitoring of the Rion Antirion bridge by Advitam: – Load Cells and Accelerometers on Stay Cables – Strain gages on the gussets of the lower anchorages of the stays) – Forces in the transverse retaining devices of the deck – Accelerometers on the pylon head, on the deck, at the pier base
and on the ground – Movement of the expansion joints – Detection of the presence of water in the Pier Base – Temperature in the pavement – Meteo Station on the deck about 300 sensors
Complementary to visual inspection and NDT ; Based on risk analysis…
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Opportunities (continued)
• SHM as an operation-critical technology (obvious Return on Investment)
Control of construction processes
Zero maintenance railway tracks
scour detection coupling AVM+structural analysis
5th generation, energy positive road
• Scalability : prefab, satellite (istimes), TDR, nanotechs
• Big data opportunities
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Tunnelling : increase productivity and safety
Early detection of preconvergence and extrusion
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Leader:
New Ballastless Tracks Project Zero maintenance makes SHM
operation critical
FUI Project
The new solution is deployed between
Gisors and Cerqueux 5 years after starting
from scratch
Highly scalable Optical Fiber continuous strain monitoring
works
Complex fatigue thermal testing at IFSTTAR confirms
the performance
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Scour detection by actual change of the structural behavior : combine the best of FEA and AVM
FB, G. Hovhanessian, E. Merliot,G. Rodovalho
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Focus on effects not on scouring phenomenon Perturbation analysis (inverse eigensensitivity)
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Scour detection= AVM+Structural engineering
Assessment of pile stiffness against overturning
2nd order perturbation yields computable range
of stiffness variation where « 1.8 » is valid
Peyrehorade bridge
AVM
Structural analysis
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On-line displacement variation for the design load (hydrostatic pressure…) or vice-versa : level 4
Structural
analysis
« SME »
Precomputes
u and w
Off-line On-line
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5RG overarching concept - Forever-open road
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Concept of the Gaia Snow-Melting System (Japan)
heated track (France, Siemens, Ifsttar)
Bast (Germany) heated road
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Scalability perspectives
• Prefabrication
• Nanotech-based sensing elements suited to low-cost fabrication and deployment process
• Satellite + airborne + ground based
• TDR
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Taking advantage of PREFABRICATION DECID2 PROJECT – Large Dimensions Plateform made of Smart Composite
with Double-SHM (M. DRISSI-HABTI et al.)
Smart Polymer-Matrix Composites : Lightweight, Corrosion-Resistant Materials that Contain Embedded Sensors
Partners : ETPO, CETIM, IDIL, IXFIBER, DFC, SYNERVIA, IFSTTAR, LARMAUR (Rennes1), GeM
PI IFSTTAR (M. DRISSI-HABTI, monssef.drissi-habti@ifsttar.fr) Support from 2 competitiveness clusters : EMC2 and PGCE Funding : Ministry of Industry, PAYS DE LA LOIRE, BRETAGNE, PICARDIE Total Budget : 3.8 M€ funding : 2.3 M€ 2 Platforms 20m x 3.5m
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DECID2 SMART COMPOSITE PLATFORM (Lightweight, Corrosion-Resistant Materials that Contain Embedded Sensors )
(IFSTTAR, Contact: monssef.drissi-habti@ifsttar.fr)
Specimen for Fatigue Testing
That Contains Embedded
Optical Fiber Sensor Ultrasonic Patchs That
were Embedded
Intervenant - date VTTI Workshop on Smart and Resilient Infrastructure 16 -17 APRIL 2 0 1 2
Long term perspective:
Massively distributed sensing elements
The « smart aggregate » concept,
Ultrasonic sensors based on CNT membranes : B. Lebental et al.
Sensing element
Energy source
Communication
device
Computing
capability
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10/07/2014
IFSTTAR Nantes Al electrodes
Sensitive composite
Asphalt
Piezoresistivity of C/sep-MWNTs over asphalt
patent ( 01/04/2014)
Load monitoring from asphalt :
graphene/sepiolite/MWNTs B. Lebental, B. Ghaddab, V. Gaudefroy, E. Ruiz, P. Aranda, C.Ruiz, B. Hennings
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Istimes E.M. sensing: part of GMES KeTs V. Cuomo, F. Soldovieri, J. Dumoulin et al.
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HIGH RESOLUTION SAR DATA Processing
The new generation of
high-resolution SAR
sensors, such
as TerraSAR-X (TSX)
and the COSMO-
SkyMed constellation,
allows the systematic
acquisition of data
with spatial resolution
reaching
metric/submetric
values.
25 TerraSAR-X Spotlight acquisitions (15 months) Azimuth resolution: 1.1m
Slant Range resolution: 0.6 m
cm/y
22
-2
Las Vegas monorail. optical view compared with deformation mean “velocity”
Award as the 2011 best paper published in IEEE Geoscience and Remote Sensing Letters
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LOW-COST scalable TDR (ECT) for health monitoring of External post-tensioned ducts (F. Taillade et al.)
Inside the bridge
Ducts
Duct: High Density PolyEthylene
Steel Cables Strand
Cement grout injected
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TDR Health Monitoring
t
Defect zone
TDR
t
Defect zone
TDR
Assuming the tapes are perfect conductors, the distributed electric impedance of the
line depends on the material filling.
Cable monitoring by electrical Time Domain Reflectometry + inverse modelling
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TDR method: results on Labéraudie bridge
Presence (observed) of void and white paste
Post-tensioned duct + electrical tape
0 5 10 15 20 25 30 35 400
5
10
15
20
25
30
35
40
x (m)
eff
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A few big data opportunities
• Big players (Telecom, utilities…) may foster massively distributed sensing
• towards linearizing the damage detection problem via
special purpose observers
relaxation of constitutive laws
• HPC on chip + Reduced Order Modelling
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Sensor placement via FE analogy
Load identification =
Finite Element approximation of a non-local problem
over the «sensor mesh»:
sensor placement formulated as mesh adaptation
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Messages
• SHM for civil structures plays a crucial role for the economy
• Consider SHM as a special case of a wider activity
smart cities and territories
connected objects, internet of everything
• Develop disruptive service-oriented sensors (+computing)
operating over wide areas
with metrological quality
that also work for SHM!
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Monitoring at urban scale http://www.parisest-sense-city.org/
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Acknowledgement
The authors wish to thank F. Soldovieri (IREA, Napoli) and colleagues from Istimes project G. Hovhanessian (Advitam), G. Rodovalho (Advitam), F. Taillade (EDF), R. Lauriot di Prevost and M. Tisseau (SIEMENS SAS / Infrastructure & Cities), Véronique Le Corvec (NECS) B. Lebental, F. Derkx, V. Gaudefroy, B. Ghaddab, E. Ruiz, P. Aranda, C.Ruiz, B.
Hennings, M. Drissi-Habti, J. Dumoulin, E. Merliot, J. Waeytens, M. Smail, Y. Gueguen, L-M. Cottineau, Th. Sedran, V. Le Cam, X. Chapeleau … (IFSTTAR)
Thank you for your attention
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Thank you for your attention
www.ifsttar.fr
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Aknowledgments
• The authors thank for their contribution :
– F. Soldovieri (IREA, Napoli),
– G. Hovhanessian and G. Rodovalho (Advitam),
– F. Taillade (EDF, previously at IFSTTAR),
– M. Drissi-Habti, J. Dumoulin, B. Lebental, B. Ghadab, E. Merliot, J. Waeytens, M. Smail, Y. Gueguen, R. Kuate, L-M. Cottineau, V. Le Cam, D. Siegert, A. Orcesi, P. Marchand, A. Khadour (IFSTTAR)
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Galileo Galilei
Misura ciò che è misurabile, e rendi misurabile ciò che non lo è
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Porticoes: SSI yields defects
Ambiant vibration monitoring at IFSTTAR Nantes (D.Siegert & Advitam)
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Frequency as a robust damage indicator
Added mass 70kg
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exploiting the best of FES
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Smart instrumentation of a motorway section : A10 Cofiroute
One example of R5G Demonstrator
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Aim : tune and assess design and building methodologies a new generation of railway track on concrete slab
Suitable for low-speed freight and high-speed passenger transport
enabling more daily traffic due to highly reduced maintenance
reliability and durability of the infrastructure : lifetime >100 years
High speed track laying > that of a ballasted track (1km/day)
reduced costs of track laying
Leader:
New Ballastless Tracks project : Zero maintenance makes SHM
operation critical
FUI Project
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thin concrete slab track + fast construction process + integrated health Monitoring (Brillouin OFS)
the market for high-speed track on concrete slab
The market in Europe focuses on Germany, Spain and France,
it is around 200 km of rail per year
expected market in China: thousands of kms
low maintenance costs
Leader:
New Ballastless Tracks
FUI Project
The new solution is NBT project Today, the reference solution system Rheda 2000
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Decoupling inverse algorithms from FES damage detection via inverse modelling
J. Waeytens, V. Le Corvec, M. Smail, FB
Structural analysis SME :
Here NECS uses ASTER
Inverse algo as a Python
supervisor
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BADIFOPS Project = Use of Ultra High Performance Concrete instrumented by Optical Fibers for earthquake-resistant applications
Transfer of strains from the host medium towards the fiber without any concrete cover effects
Existing Solutions:
Iten M. “Novel applications of distributed fiber optic sensing in geotechnical engineering” PhD dissertation
ETH-Zürich 2011.
Leng JS et al., Sensors and Actuators A-PHYSICAL, 2006 126(2) 340-347.
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> Originalité des travaux réalisé dans le cadre du projet BADIFOPS
- The fibers are monomod SMF-28 (with a primary coating). Fibre optique
Barre d’acier
Transfer des déformations
- Localization of embedded fibers in a recess (trench)
Polyimide Elasticity modulus (MPa) 2400 Resistance (traction) (MPa) 130 Temperature of functioning -65°C à +300°C Coefficient of thermal expansion 0.5×10-6 /K à 20 °C Resistance to statical fatigue Yes Chemical Durability Bad Mechanical Protection Very bad Transmissibility of deformations Excellent
- The glue between the bar and the primary coating
Fiber
Glue
Steel
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