6707_Presentacion_G_Hovhanessian.pdf

8/10/2019 6707_Presentacion_G_Hovhanessian.pdf

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Instrumentacin de Puentes

Structural Health Monitoring of Bridges


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Agenda

Some examples

Focus on Rion Antirion System

General architecture of Structural Health Monitoring System

! Data management & long term storage system

! Data acquisition & temporary storage system

! Sensors for characterization of effects vs loads

! Sensors for monitoring of ageing


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SOME EXAMPLES


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Russky Island Bridge

Unique signature bridge

Worldwide longest cable stayedspan

! 1104m main span

Very aggressive environment

Monitoring is a key tool to evaluate

real bridge behavior and confirm

design hypothesis


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Normandie Bridge

Long span cable stayed bridge

! 2141m long, 854m main span

Built in 1995

! Worldwide longest at the time

Comp lementa ry mon i to r i nginstalled after 20 years

! Focus on bridge ageing and durability

" Acoustic monitoring of stay cables

" US inspection of anchorages

Acoustic sensors

Accelerometers on

stay

Expansion joint

movements

sensors

Tiltmeters

Deck temperature

sensor

Water presence

sensor

Load cell

Load cell


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Grande Ravine Viaduct

Construction monitoring! Check geometry in real time

! Adjust tension in cables as needed

Operation monitoring

! Monitor wind loads

! Monitor bridge response during windevents

Load cell

Tiltmeters

Tri axial

anemometer

Differential air

pressure sensors

Structural

accelerometers

(1D, 2D, 3D)

Indoor and outdoor

temperature

sensors


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Astana Arch Bridge

Monitoring during load test! Static

! Dynamic

Design check before

bridge opening T(V

Strain gages


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Penang Bridge

Underestimation of fatigue loads atconstruction stage

Crack in stay detected during

maintenance works

Preventive acoustic monitoring ofall stays

Acoustic sensors


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ASF Highway viaduct

Local corrosion found in somecables

Extend of the problem is notknown

Acoustic monitoring is placed on all

beams

External posttensioning is added

Post tensioning can be adjusted if

progress of deterioration isdetected

Acoustic sensors

(UPUS


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Bosporus Bridges 1 & 2

Traffic load more important thanexpected

! Risk of fatigue on some critical steelcomponents

Tempora r y mon i t o r i ng f o r

assessment of actual condition ofthe two bridges

Permanent monitoring left in place

on B1

! Continuous monitoring of fatigue

! Automatic alarm in case of storm or

earthquakes

(UPUS

measurement)

Tri axial

anemometerWeather station


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Frontera

Instrumentation installed duringretrofitting of piers in 2013

Monitoring of traffic loads

! Weight in motion sensors

! Deck strain

Monitoring of piers / scouringeffect

! Water level and speed

! Pier tilting and natural frequencies

Tri axial

anemometer,

weather station

and structural

temperature

Expansion joint

movementssensors

Weight in Motion

sensor

Strain gages

Camera


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FOCUS ON RION ANTIRION EXAMPLE


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Rion-Antirion environment & design loads

R!"N #

65 m.

PROJECT BRIEF DESCRIPTION#RION-ANTIRION ENVIRONMENT & DESIGN LOADS

Design Loads:

" Earthquake with a return period of 2000 yrs or 5%

possibility of exceedance in 120 yrs (operational life)

"Tectonic movements of 2m in all directions betweenadjacent piers

"

Wind speeds up to 266km/h"Ship collision of 180000t DWT approaching at a

speed of 16 knots


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Definition of the system

1 2

3

Likelihood

Severity General surveillance : visual, ndt, post inciInspection & Maintenance Manual

Continuous monitoring: when visual inspection is not suff

(no detection, not enough reactivity or too expensive)

Structural Risk Analysis


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Structural Monitoring System

~ 300 sensors

Real Time Information, up to 500 Hz per channel

Fully customizable system

Specified during design

Installed to follow construction

Used to manage operation

Maintenance Management" Detection of defects

" Control of maintenance actions

Traffic management

Design calculations"

Identification of real load cases

" Validation of models


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Monitoring strategy & thresholds defined with design/construction te

EARTHQUAKE !

Automatic modification ofacquisition parameters

Automatic Data treatment and

classification of earthquakes in 3 cases

(small, moderate, strong)

Automatic Report, Mail andPhone Call

Automatic event detection

Accelerometer and characterization


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Accelerometer(Pier Base) Water presence

(Pier Base)

Acceleromet(Shore)

Expamo

Force intransverse

retaining device

Accelerometers(deck)

Temperature(pavement)

Strain gages(gussets)

Meteo Station(deck)

Accelerometers(Stay Cables)

Load Cells (StayCables)

(Pylon Head)

Sensors for earthqua

determination (struct

Sensors for long term

and operation


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GENERAL ARCHITECTURE OF STRUCTURAHEALTH MONITORING SYSTEM


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System Overview

WeighSensor

StaticSensors

GPSreceivers

DWIMSDAU

StaticDAUs

GPS DAU

Sensors Network of digitizersData Acquisition and Temporary

Storage System

Raw, processed,historical, event &

condition data

DynamicSensors

DynamicDAUs

Data visualization, posprocessing, analysis a

report generation

TDSS Server

Temporary DataStorage System

Local

access

Data Management and Long TermStorage System

Raw, processed,historical, event,

condition data & alertdata

LTSS Server

Long Term DataStorage System

Cloudaccess

Alert

OpticalSensors

OpticalDAUs

& &

MobileSensors

PortableDAUs

Basic visuanalysis


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What do we expect from the SHM System ?

To takerelevantdecision

To assesrealbehaviour

To

calibratemodels

To

monitorageing

To detechiddendefects

W b l tf f l t d t t


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Web platform for long term data management

Data & alert indicators shall be integrated to the BridgManagement System and available to all stakeholder

Decision is taken from Inventory data + visual inspection maintenance history + other constrain

f h ll b d d h


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Acquisition frequency shall be adapted to each case

Periodic visual

inspection

Main surveillance method

Periodic

measurement

When relevant informationis not visible (ex: stress;

hidden defect)

When loads and effectsshall be recorded at slow

time steps (say > 1/month)

Continu

Monitor

When measuremebe periodic (ex: a

monitoring

When quick reacneeded (earthquak

redundancy

When loads and shall be recorded

time steps (say < 1

E l f t bl DAU f i di


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Example of portable DAUs for periodic measureme

Tension measureme

Stress measurement in concrete

Vibration measurement of cables

Load test

Wi l t k


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Wireless sensor network

Quick deployment

Local communication byradio

Remote communication byGSM

Up to 5 years autonomy

One channel battery powered wireless nodes

Four channels wireless nodes with so

Wired DAU


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Wired DAU

For complex situations asfor example long term

dynamic systems

Customized on demand! Integrat ing d i f ferent sensor

technologies (analog, vibrating wire,optical, )

! I n t eg r a t i ng wa t c hdog s f o roptimization of uptime

! Integrating NF EN 61643-21lightning protection

! Integration real time data analysis

!

Use of SHM System


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Use of SHM System

Data will be used to calibratemodels!

Simultaneous measurement of loads andeffect of loads (displacement, strain,force)

! E x p e r i m e n t a l m o d a l a n a l y s i s(identification of Eigen modes)

Hidden de fec t s w i l l beidentified by! Dedicated sensors / abnormal values

! Changes in load vs effect relationship

Thresholds shall be definedwith engineering team

Acquisition & alert strategy


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Acquisition & alert strategy

Raw data is processed contin! Filtering

! Scaling

! Calculated channels

Only relevant informat

recorded

! Event data

! History data

-10

-5

0

5

10

15

0 50 100 150 200

-10

-5

0

5

10

15

0 50 100 150 200

Raw/Processed data: not recordedExample: strain/temperature

Event data: Short record of raw/calculated data

History data: (ex: average, max, min, std,Calculated statistics over a period

-3

-2

-1

0

1

2

3

4

0 50 100 150

threshold

Monitoring of loads


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Monitoring of loads

2D & 3D anemometer & weather station (Temperature, air pressure, relative humidity,sun, rainfall)

Weigth In Motion (WIM) Seismic Accelerometer

Water level & spe

Accelerometer for shock

Monitoring of strain & displacement


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Monitoring of strain & displacement

Weldable strain gages

Long base (20cm) displacement sensor

Embedded strain gages

Long base (1m) invar displacementsensor

1D & 3D crackmet

Wire displacement se

Monitoring of movements


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Monitoring of movements

Accelerometers on stay

Differential GPS

Accelerometer on deck

Total station

Tiltmeter

Crack propagation se

Monitoring of stress & force


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Monitoring of stress & forceLoad cell

UPUS measurement for bars

Electromagnetic sensors

SlotStress mfor con

Monitoring of hidden defects


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Acoustic monitoring

! Grid of sensors is glued on the area t

! Detects sound released during a brea

! Events are located by triangulation



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Continuous strain sensors

Strain increase at cracklevel

Cracks are detected beforethey are visible

Can be used to detect

early sign of deteriorationis concrete structures


Monitoring of corrosion or fatigue risk


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Monitoring of corrosion or fatigue risk

Corrosion ladders: monitoring of corrosion potential and current

Single steel anodes at different depths for the monitoring of the time-

dependent chloride ingress or carbonation progress into the concrete

Dynamic strain/force sensors for fatigue monitoring

Rainflow algorithm for fatigue monitoring (load cycle

Monitoring of corrosion or fatigue effect


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Monitoring of corrosion or fatigue effect

Example of white paste in external post tensioning duct Example of corroded strand with broken wire

Uscan: detection of corroded or broken wiresEscan: detection of voids and white paste

Conclusion


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Conclusion

Structural Health Monitoring is very efficient tool complementary to pvisual inspections

For maximum efficiency, It should be designed with the engineering te

It can be tuned to any structure

And will provide data helping managers and engineers in managinbuilding assets


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Thank you for your attention

6707_Presentacion_G_Hovhanessian.pdf

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