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?