Structural health monitoring and concept of sustainability in
engineering
Princeton University, Supélec, Ecole Centrale Paris and Alcatel-Lucent Bell Labs Workshop on Information, Energy and Environment, June 23-24, 2008
Presented by Branko GlišićSMARTEC SA, Switzerland
Outline
• Challenges of modern world
• Concept of sustainability in civil engineering
• Structural health monitoring as a support to concept of sustainability
• Examples from practice
• Closing remarks
• Protection of natural environment• Maintenance of built environment• Approaching the lifetime limits of
civil infrastructure • Mitigation risks from natural or
human-made disasters• Shortage of fresh water• Shortage of energy• …
Challenges of modern world
Concept of sustainability• New construction materials and new structural
systems to be developed and applied• New structures to be performance oriented
and old structures rehabilitated or recycled• Long-term maintenance programs are to be
implemented• Implementation of structural health monitoring
as a tool providing objective and reliable real-time information on structural performance and condition
MONITORING =Periodical or continuous record ofparameters over a certain periods(long-term, short-term or comb.)
PARAMETERS =
Mechanical (strain, curvature,…)Physical (temperature, humidity,…)Chemical (PH, CL-, SO3
-, …)Other
LEVEL =MaterialLocal structuralGlobal structural
Monitoring and monitored parameters
Pain Diagnosis CureExams
Monitoring Inspection RepairDiagnosis
SHM – nervous system of structure
Why monitoring?
• Increase safety preserve human lives, environment and goods
• Management based on objective and reliable data decrease of economic losses due to repair, maintenance, reconstruction and for users
• Better exploitation of traditional materials, better exploitation of existing structures reducing of construction and exploitation costs
Why monitoring (continued)?
• New materials, new construction technologies, new structural systems are used increase of knowledge, control of design, verification of performance, creation and calibration of models
• Plan and reduce life-cycle operation costs
• Limit social, economical, environmental and aesthetical impact in case of deficiency
• Supports concept of sustainable engineering
Fiber Optic methods for SHM, FESHM and Integrity Monitoring
SHM Methods - Challenge / MotivationBest monitored structure Concept of nervous system directly
applicable to the structures?Sensors everywhere
Complex, complicated and expensive!
Finite Element SHM concept
“Simple” topology
“Parallel” and “crossed” topologies
“Parallel” and “triangular” topologies
“Parallel” topology
Tilt
m
eter
• Structure is divided into parts called cells
• Results obtained from each cell are linked, using appropriate algorithms, in order to retrieve the global structural behavior
• Each cell is equipped with long-gage fiber optic sensor combination, called a topology, which in the best manner corresponds to the expected strain field in the cell
FESHM, different types of structures
Integrity monitoring
Average strain []
Event that generate local strain change
Expected average strain without damage
• Distributed fiber optic sensing provides for integrity monitoring – event (e.g. damage) detection and localization
Distributed deformation sensors for integrity monitoring
Event detection and localization
Integrity monitoring applications Distributed deformation sensor for integrity monitoring
Distributed sensors in sections, along vaults,
in boreholes
Distributed deformation and temperature sensor
Seepage Overflow
Slow local movement in slope
Diff
eren
t m
odel
s vs
. m
onito
ring
SHM example – I10 bridge (US)High performance pre-stressed concrete (new material)Model? Performance?
Performance from monitoring
Recycled pipes as pilesPerformance? Safety?
SHM example – Swiss Expo ‘02
C.M.P.
Old structure (1939) – fatigue cracks in steelMaintenance, in-time repair – lifetime extension until 2020
SHM example – Gota bridge (SE)
Integrity monitoring over 5 main girdersBridge open
Position
Ave
rag
e st
rain
[ ]
The largest hydropower plant in Latvia Risk of shortage of energy in case of structural failureDisastrous impact to environment
SHM example – Pļaviņu hes (LV)
Ear
ly w
arni
ng,
in-t
ime
mai
nten
ance
SHM example – Prezzo (IT)Village built on landslide – risk for population and goods
Land sliding accelerated with rain and snow melting
Monitoring for mitigation risk
SHM example – ZEM (EU)Composite onboard storage tank for gas powered vehiclesLow weight/consumption/emissionsSafety/periodic controls/maintenance
SHM example – Vienna water supplyCity’s 2nd water supply line, aged (built in 1900)
Cracks present in tunnel, important losses of water
Monitoring to improve water management
Gas tank construction in a salt mine near Berlin
Cleaning of salt mine with hot water, evacuation of the brine using 55 km pipeline
Risk of structural failure / 3rd party interference / leakage
Safety, ecological consequences, interruption of construction process, delay and economical losses
SHM example – Brine pipeline (DE)
Source: GESO, Jena, Germany
Acknowledgements
• New Mexico State University (US)• Swiss Expo ’02 (CH)• Norwegian Geotechnical Institute (NO)• Trafikkontoret (SE)• Latvenergo, VND2 and Aigers (LV)• EU Commission and ZEM partners (EU)• Vienna Water Supply and RISS (AT)• GESO (DE)
Instead of conclusions
Butterflies and dinosaurs date from the same epoch…
Recent research leads scientists to the conclusion that butterflies have survived because they have been
equipped with better sensors than dinosaurs, and thus are able to adapt to environmental changes.
Should we build structures with a butterfly or dinosaur destiny?