Instrumentación de Puentes - AMIVTAC · Advitam Normandie Bridge ! Long span cable stayed bridge ! 2141m long, 854m main span ! Built in 1995 ! Worldwide longest at the time ! Complementary

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Instrumentación 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 stayed span

!  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 l emen ta r y mon i t o r i ng installed after 20 years

!  Focus on bridge ageing and durability "  Acoustic monitoring of stay cables "  US inspection of anchorages

Acoustic sensors Uscan Survey

Accelerometers on stay

Expansion joint movements

sensors

Weather station

Tiltmeters

Deck temperature sensor

Water presence sensor

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 wind events

Load cell

TiltmetersLong base

extensometers

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

! Des ign check be fore bridge opening Tension in stay

(Vibration method)

Strain gages

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Penang Bridge

! Underestimation of fatigue loads at construction stage

! Crack in stay detected during maintenance works

! Preventive acoustic monitoring of all stays

Acoustic sensors

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ASF Highway viaduct

! Local corrosion found in some cables

! Extend of the problem is not known

! Acoustic monitoring is placed on all beams

! External posttensioning is added

! Post tensioning can be adjusted if progress of deter iorat ion is detected

Acoustic sensors

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Bosporus Bridges 1 & 2

! Traffic load more important than expected

!  Risk of fatigue on some critical steel components

! Tempo r a r y mon i t o r i n g f o r assessment of actual condition of the two bridges

! Permanent monitoring left in place on B1

!  Continuous monitoring of fatigue

!  Automatic alarm in case of storm or earthquakes

Cable clamps (UPUS

measurement)

Expansion joint movements

sensors

Tri axial anemometer

Weather station

Hanger force transducers (with invar mechanics)

Differential GPS

TiltmetersDeck & Pylon

Dynamic strain gages (1, 21 3D)

(stools, hanger pin, cable clamps)

Structural accelerometers

(deck, pylon, hanger)

Structural temperature (deck,

pylon, hanger, main cable)

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Frontera

! Instrumentation installed during retrofitting of piers in 2013

! Monitoring of traffic loads !  Weight in motion sensors

!  Deck strain

! Monitoring of piers / scouring effect

!  Water level and speed

!  Pier tilting and natural frequencies

Tri axial anemometer,

weather station and structural temperature Tiltmeters

Structural accelerometers

(1D, 2D, 3D)

Expansion joint movements

sensors

Weight in Motion sensor

Water speed & level

Strain gages

Camera

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FOCUS ON RION ANTIRION EXAMPLE

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Rion-Antirion environment & design loads

RΙΟN ΑΝΤΙRΙΟN

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 between adjacent 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 incident = Inspection & Maintenance Manual

Continuous monitoring: when visual inspection is not sufficient (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 team

EARTHQUAKE !

Automatic modification of acquisition parameters

Automatic Data treatment and classification of earthquakes in 3 cases

(small, moderate, strong)

Automatic Report, Mail and Phone Call

Automatic event detection

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Accelerometer (Pier Base) Water presence

(Pier Base)

Accelerometer (Shore)

Expansion joint movement

Force in transverse

retaining device

Accelerometers (deck)

Temperature (pavement)

Strain gages (gussets)

Meteo Station (deck)

Accelerometers (Stay Cables)

Load Cells (Stay Cables)

Accelerometer (Pylon Head)

Sensors for earthquake detection and characterization

Sensors for earthquake case determination (structural response)

Sensors for long term management and operation

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GENERAL ARCHITECTURE OF STRUCTURAL HEALTH MONITORING SYSTEM

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System Overview

Weigh Sensor

Static Sensors

GPS receivers

DWIMS DAU

Static DAUs

GPS DAU

Sensors Network of digitizers Data Acquisition and Temporary Storage System

Raw, processed, historical, event &

condition data

Dynamic Sensors

Dynamic DAUs

Data visualization, post processing, analysis and report generation

TDSS Server ∑

Temporary Data Storage System

Local access

Data Management and Long Term Storage System

Raw, processed, historical, event,

condition data & alert data

LTSS Server

∑ Long Term Data Storage System

Cloud access

Alert

Optical Sensors

Optical DAUs

… …

Mobile Sensors

Portable DAUs

Basic visualization & analysis

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What do we expect from the SHM System ?

To take relevant decision

To asses real

behaviour

To calibrate models

To monitor ageing

To detect hidden defects

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Web platform for long term data management

Data & alert indicators shall be integrated to the Bridge Management System and available to all stakeholders

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

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Acquisition frequency shall be adapted to each case

Periodic visual inspection

Main surveillance method

Periodic measurement

When relevant information is not visible (ex: stress;

hidden defect)

When loads and effects shall be recorded at slow

time steps (say > 1/month)

Continuous Monitoring

When measurement cannot be periodic (ex: acoustic

monitoring)

When quick reaction is needed (earthquake; lack of

redundancy)

When loads and effects shall be recorded at faster

time steps (say < 1/ month)

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Example of portable DAUs for periodic measurement

Tension measurement in bars

Stress measurement in concrete

Vibration measurement of cables

Load test

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Wireless sensor network

! Quick deployment

! Local communication by radio

! Remote communication by GSM

! Up to 5 years autonomy One channel battery powered wireless nodes

Four channels wireless nodes with solar panel

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Wired DAU

! For complex situations as for example long term dynamic systems

! Customized on demand !  In tegra t ing d i f fe rent sensor

technologies (analog, vibrating wire, optical, …)

!  I n t e g r a t i n g w a t c h d o g s f o r optimization of uptime

!  Integrat ing NF EN 61643-21 lightning protection

!  Integration real time data analysis !  …

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Use of SHM System

! Data will be used to calibrate models

!  Simultaneous measurement of loads and effect 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)

! H idden de f e c t s w i l l b e identified by

!  Dedicated sensors / “abnormal values” !  Changes in load vs effect relationship

! Thresholds shall be defined with engineering team

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Acquisition & alert strategy

! Raw data is processed continuously !  Filtering

!  Scaling

!  Calculated channels

! Only relevant information is 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 recorded Example: 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 50 100 150 200

threshold

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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 & speed

Accelerometer for shock detection

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Monitoring of strain & displacement

Weldable strain gages

Long base (20cm) displacement sensor

Embedded strain gages

Long base (1m) invar displacement sensor

1D & 3D crackmeter

Wire displacement sensor

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Monitoring of movements

Accelerometers on stay

Differential GPS

Accelerometer on deck

Total station

Tiltmeter

Crack propagation sensor

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Monitoring of stress & force Load cell

UPUS measurement for bars

Electromagnetic sensors

SlotStress measurement for concrete

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Monitoring of hidden defects

! Acoustic monitoring

!  Grid of sensors is glued on the area to monitor

!  Detects sound released during a break

!  Events are located by triangulation

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! Continuous strain sensors

! Strain increase at crack level

! Cracks are detected before they are visible

! Can be used to detect early sign of deterioration is concrete structures

Monitoring of hidden defects

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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 counting)

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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 wires

Uscan: detection of corroded or broken wires Escan: detection of voids and white paste

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Conclusion

! Structural Health Monitoring is very efficient tool complementary to periodic visual inspections

! For maximum efficiency, It should be designed with the engineering team

! It can be tuned to any structure

! And will provide data helping managers and engineers in managing their building assets

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Thank you for your attention