Application of Distributed Fiber Optic Sensing Technology...

ISSAEST, Fairbanks, AK, USA, August 2-5, 2015

Application of Distributed Fiber Optic

Sensing Technology in the Transportation

Engineering Monitoring

Bin Shi, Ph.D.

Nanjing University, China

August 5, 2015

Nanjing University The Monitoring Characters of Transportation Engineering

Linear and longer Large scale

Complicated Geological condition Harsh working environment

Nanjing University

The conventional monitoring technologies have some

disadvantages such as point monitoring, difficult to install,

poor anti-interference, poor durability and poor stability etc.,

so they don’t meet the monitoring requirements of modern

transportation engineering.

Developing tendency of monitoring technology

Nanjing University

In past decades, fiber optic sensing (FOS)

technology is rapidly developing, and its

monitoring advantages with distributed,

long-distance, small size , totally immune to

EMC perturbations, long lifetime etc.

provide a new way to monitor transportation

engineering and other infrastructure

engineerings

Nanjing University Fiber Optic Sensor Root

Charles Kuen Kao GBM,KBE,FRS, FREng (born 4 November 1933) is a Chinese-born Hong

Kong, American and British electrical engineer and physicist who pioneered

in the development and use of fiber optics in telecommunications. Kao,

known as "Father of Fiber Optic Communications", was jointly awarded the

2009 Nobel Prize in Physics for "groundbreaking achievements concerning

the transmission of light in fibers for optical communication".

Nanjing University What is Distributed FOS?

Point Quasi-distributed Fully Distributed

•Point : such as Mechelson and Fibry-Perot sensor

•Quasi-distributed: FBG (Fiber Bragg Grating )

•Fully Distributed: OTDR, ROTDR, BOTDR/A

Nanjing University

DFOS –based Monitoring Prototype for Infrastructure

Nanjing University

2015-8-10 8

DFOS Family

DF

OS

Fam

ily

Fibre Bragg Grating （FBG）

Optical time domain reflectometry(OTDR）

Raman OTDR（ROTDR）

Brillouin OTDR (BOTDR）

Brillouin OTD Analysis（BOTDA）

Multi-use

Scatter light

8

Brillouin Optical frequency domain

analysis (BOFDA）

……………

Nanjing University DFOS Monitoring System

Nanjing University

Fiber

grating

Grating

series

FBG

Sensors

Modulator

s

Monitoring

System

FBG

Products

迷你

土压力计微型渗压计液位计静力水准仪孔压计位移计

温度计

（工业）钢筋应力计埋入应变计

温度计

（电力）表面应变计缆式应变计锚索测力计土压力计

温度计

（岩土）

Pressure & osmometer Displace & Stress Temperature Strain & Deformation

FBG Product Series

FBG Modulators

Nanjing University

Optical indexes

Number of channels 1

Wavelength range (nm) 1525 ~ 1565

Wavelength resolution (pm) 1

Repeatability (pm) 5

Response Frequency 1~5

Dynamic range (dB) 40

Channel spectrum Can be queried

Optical interface type FC/APC

Maximum FBG Sensor Capacity per channel 20

Other indexes

Display type 3.5 inch LCD screen

Resolution 480*320

Communication interface USB

Power supply 9VDC(With the AC power adapter)

Power consumption （W） 5

Operating temperature（℃） -10 ~ 50

Operating humidity 0~80% (no condensation)

Storage temperature（℃） -20 ~ 60

Storage humidity 0~80% (no condensation)

Dimensions（length * width * height）（mm）

251*150*43

Weight（kg） 1.3

Hand FBG Modulator

Nanjing University

Optical indexes

Number of channels 2

Wavelength range (nm) 1525 ~ 1565，1510-1590

Wavelength resolution (pm) 1

Scan Frequency（Hz/channel） 2

Dynamic range (dB) 50

Channel spectrum Can be queried

Power supply 9VDC

communication USB,RF,Internet,WiFi

Operating temperature（℃） -10 ~ 50

Dimensions（mm） 325*275*140

Weight（kg） 4.4

Portable FBG Modulator

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FBG etching Coating

Welding Assembling

Manufacture of FBG sensors

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Modulators Sensing cables

Monitoring System

Services DSS Products

DSS Product Series

Surface Interior Point

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BOTDR

（EI41，China）

item parameter

Measure mode Single-end

Measure accuracy 45 με

Spatial resolution 50 cm

Measure max. Distance Max 80 Km

Measure time 120-600S

DSS Modulators (1)

item parameter

Measure mode Single-end

Max. measure accuracy 2με

Spatial resolution 1-5mm

Measure distance Max 100m

Measure frequency 5-100HZ OFDR

（ Luna，USA ）

Nanjing University

Item parameter

Measure mode Double-end

Max. measure accuracy 7.5 με


Measure distance Max 25 Km


DSS Modulators (2)

Item parameter

Measure mode Double-end

Measure accuracy 2 με


Measure distance Max 25 Km


BOFDA

（ FibrisTerre，Germany ）

BOTDA

（ Neubrex，Japan ）

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Fiber drawing and coating equipment Bare fiber

Fiber extrusion equipment Tight package soft cable

Manufacture of Sensing Optical Fiber

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Smart GFRP anchor

Manufacture and connection of smart GFRP anchor

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Strain sensing cable

Strain & Temp sensing cable

Sensing Cables

Nanjing University

Item Parameters

Optical fiber type G.652B

Cable type metal-based

Fiber quantity 2 (S&T)

Cable sectional dimensions 15mm*0.15 mm

Tensile strength (N) 280

Cable weight (kg/km) 18

Metal-based S & T sensing belt

fiber

Porous copper belt

Production line Metal-based sensing belt

Nanjing University

Steel-pipe pile Point welding

Glued by epoxy End protection

Installed on the steel-pipe pile

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Item Parameters


Cable type metal-based

Fiber quantity 1

Cable sectional

dimensions Φ5


Cable weight (kg/km) 38

Steel-strand sensing cable

Steel-strand twisted and weaved equipment Steel-strand sensing cable

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Strapping End protection

Pile forming Grouting

Installed in the cast-in-place pile

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Implanted in borehole

weight dropped into borehole grouting protection

Steel-strand sensing cable

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Item Parameters


Cable type HY

Fiber quantity 1

Cable sectional dimensions Φ 0.9-2.0

Tensile strength (N) 25-38

Cable weight (kg/km) 3-8

grooving Embedded in Epoxy seal End protection

Implanted into PHC Pile

Soft tight-packed strain sensing cable

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trenching point fixation laying the fiber covering

Item Parameters


Cable type point to point

Fiber quantity 1

Cable sectional dimensions Φ 4.5-8.0


Step length (m) 1-20 Implanted into soil

Point fixed strain sensing cable

Nanjing University

• Modulator Sensing

cable Monitoring

System Service DTS Products

DTS Product Series

扁平型纤维加

强温度传感光

缆

金属基装温

度传感光缆金属基装温度传感光缆

高强度铠

装测温光

缆

钢丝编织网

铠装光缆

塑封芳纶夹钢

丝编织管铠装

光缆

无缝管铠

装感温光

缆

中心管束

式温度传

感光缆

钢丝加

强铠装

光缆

单层钢丝加

强中心管束

感温光缆

ROTDR ROFDR

Nanjing University

Item Parameters

Optical fiber type MM

Cable type heatable

Fiber quantity 1-3

Cable sectional dimensions Φ 3-8


Heating power(w/m) 6-20

Carbon fibre heatable temperature sensing cable

Nanjing University

Case one:

Xuanwu-lake tunnel FOS monitoring

Nanjing University

Based on many experiments, the jacketed SM optical fiber

from Corning Co Ltd is selected as sensor.

Specification:

8.3/125/900/m (core/cladding/protective coating);

Weight: 0.9 kg/km;

Maximal tension: 6.6 N;

Minimum bending radius: 3.0 cm

Compressive strength: 200 N/m;

Working temperature: -20~+80 C;

Working wavelength: 1.3~1.5 m;

Refractive index error: 0.36%;

Project scheme

Selection of the optical fiber

Nanjing University

Nanjing University

FOS sensing fibers were installed on the surface of

the concrete wall and arch with three configurations:

(1)Overall Adhesion Method (OAM)

(2)Fixed-point Adhesion Method (FAM)

(3) -shaped Fixed-point Adhesion Method (-FAM)

Installation of BOTDR sensing fibers

Nanjing University The Layout of Optical Fiber Installation

Fiber

cable

Nanjing University The installation profile of Sensing fibers

2015-8-10 36

Southern tunnel Southern tunnel

Location of sensing fiber

Groove size

Tridimensional layout of sensing fibers installation on the arch

Nanjing University

Nanjing University

Deformation distribution of expansion and contraction

joint along the Tunnel (1)

2015-8-10 40

Position No.

Position ( from South Entrance)

m

Maximum

(mm)

Minimum

(mm)

SP 13

450

0.139

-0.022

SP 15

405

0.128

-0.025

SP 17

355（near center）

0.094

-0.021

SP 21

256

0.103

-0.004

SP 23

190

0.135

-0.015

SP 25

38

0.127

-0.008

SP 27

114

0.142

-0.007

Nanjing University

2015-8-10 41

600 800 1000 1200 1400 1600 1800

-0.2

0.0

0.2

0.4

0.6

应变

/%

距离 /m

传感光纤末端

自 2003年9月30日至2003年11月3日

温度伸缩缝

{

混凝土衬砌

Deformation distribution of expansion and contraction

joint along the Tunnel (2)

expansion and contraction joint

Sensing fiber end

Concrete section From 30/9/2013 to 3/11/2013

Distance/m

Nanjing University

2003-5-22

2003-6-23

2003-7-21

2003-8-26

2003-9-30

2003-10-21

2003-11-17

2003-12-18

2004-1-16

2004-2-22

-400

-200

0

200

400

600

800

0

10

20

30

40

气温 (

℃)

应变

()

日期

525

595

626

735

830

920

1040

1130

1250

1370

1460

1550

1640

1730

气温

S4线典型点有效应变变化

2015-8-10 42

temperature

str

ain

tem

pera

ture

date

Negative correlation between temperatures and strain values of Line S4

Nanjing University

Abnormal values monitored by BOTDR at 90m

2015-8-10 43

540 560 580 600 620 640-200

0

200

400

600

800

1000异常

异常

545- 635段应变

2003-4-25

2003-5-12

2003-6-2

2003-7-7

2003-7-30

Abnormal value

Abnormal value 545-635m section

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Case two: Application into the pavement monitoring

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0 2 4 6 8

-120

-100

-80

-60

-40

-20

0

20

40

60

80

100

应变

（）

距离（m）

0 小时 31 小时 55 小时 80 小时 104 小时

The surface strain distribution after grouting 104hrs

extension compression

Cracking area

distance

str

ain

distance

Some of test results (1)

Nanjing University

0 2 4 6 8

-120

-100

-80

-60

-40

-20

0

20

40

60

80

100

应变

（）

距离（m）

0 小时 31 小时 55 小时 80 小时 104 小时

The strain distribution of interior steel rebar S9 after grouting 104hrs

str

ain

distance

Some of test results (2)

Nanjing University

电力系统

海洋开发

建筑系统

化工系统

Application of Raman OTDR（ROTDR）

高速公路地基温度监测系统


The DTS of the pavement of highway

高速公路路面结冰监测系统


The DTS of the road surface freezing of highway

Nanjing University Conclusion

DFOS, as an innovative sensing technology, is very useful

and powerful to monitoring transportation engineering. However,

some of further R & D work need to do, such as: low-cost

demodulator; special sensing cable for measurement of large

deformation; improvement of manufacture and installation

technology; software to deal with huge data, and code making

etc.

However we do believe that DFOS will have a huge

application in the infrastructure monitoring including

transportation and geo-engineering.

Nanjing University

In 2005，under the support of National Natural Science Foundation of China, our team set

up International Forums on Opto-electronic Sensor-based Monitoring in Geo-engineering

(OSMG) in Nanjing University. Now five Forums have been successfully held in 2005,

2007, 2010, 2012, 20014 respectively.

International Forums on Opto-electronic Sensor-based Monitoring in Geo-engineering (OSMG)

Nanjing University Acknowledgment

It is grateful that the project is supported by

National Basic Research Program of China（973 Program）（NO.

2011CB710605)

National Key Project of Scientific and Technical Supporting

Programs Funded by Ministry of Science and Technology of China

（NO. 2012BAK10B05）,

The State Key Program of National Natural Science of China

(Grant No. 41230636 )

Nanjing University

Application of Distributed Fiber Optic Sensing Technology...

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