apss2010, 2 aug., tokyo - bridge & structure · pdf filemajor arch bridges completed or...

APSS2010, 2 Aug., Tokyo

Limin Sun, Tongji Univ. 1

Chinese Bridges and Health Monitoring Systems

Limin Sun, Tongji.Univ., China APSS2010 1

Limin Sun

Department of Bridge Engineering, Tongji University, Shanghai, China

Contents

• Chinese bridges–Historic bridges

–Modern bridges

• Structural health monitoring (SHM) systems–SHM for bridge in China


–Case study –SHM for Donghai Bridge

–Performance diagnosis

–Consideration on design of SHM system

Chinese historic bridges


Chinese historic bridges


Zhaozhou Bridge (BC605), Hebei

Step Bridge, Zhejiang

Pingan Bridge (BC1152), Fujian

Chinese historic bridges (cont.)


Luding Bridge (BC1702), Sichuan


Lounge Bridge ZhejiangHong Bridge Henan


Chengyang Bridge (BC1924), Guangxi

Lounge Bridge, ZhejiangHong Bridge, Henan




Qiantang River Bridge


Wuhan Yangtze River Bridge (BC1957), Hubei

Qiantang River Bridge(BC1937), Zhejiang

Summary（1）

• Bridge structural types–girder, arch, suspension, cable-stayed

• Materials–timber, stone, iron & steel, concrete, CFRP?


• Durability–stone > wood >? iron & steel, concrete

Chinese modern bridges

Limin Sun, Tongji.Univ., China APSS2010 9 Limin Sun, Tongji.Univ., China APSS2010 10

Major cable-stayed bridges completed or under construction in China（L≥400m）

NO. Pictures Name LocationMain

Span/mYr.of

Completion Type

1 Nanpu Bridge Shanghai 423 1991

Steel‐concrete Composed Beam

2Yunyang Bridge over Han River

Hubei Prov. 414 1993 Concrete

Beam


3 Yangpu Bridge Shanghai 602 1993


4Tongling Bridge over Yangtze

River

Anhui Prov. 432 1995 Concrete

Beam

52nd Wuhan Bridge over Yangtze

River


Beam

continue

NO. Pictures Name Location Main Span/m

Yr.ofCompletion

Type

62nd Chongqing

Bridge over Yangtze River

Chongqing 444 1996 Concrete Beam

7 Xupu Bridge Shanghai 1996 1996 Hybrid Beam


8 Ting Kau Bridge Hongkong 475 1997


9Kap Shui Mun

Bridge Hongkong 430 1997 Hybrid Beam

10Shantou Queshi

BirdgeGuangdong Prov. 518 1998 Hybrid Beam



continue


Span/mYr.of

Completion Type

11Baishazhou Bridge over Yangtze River

Hubei Prov. 618 2000 Hybrid Beam

12Qingzhou Bridge over Min River

Fujian Prov. 605 2001

Steel‐concrete Composed B


Beam

132nd Nanjing Bridge over Yangtze River

Jiangsu Prov. 628 2001 Steel Box

Girder

14Jingzhou Bridge over Yangtze River


Beam

15Dafosi Bridge over Yangtze River Chongqing 450 2002 Concrete

Beam


Span/mYr.of

Completion Type

16Junshan Bridge

over Yangtze RiverHubei Prov. 460 2002 Steel Box

Girder

17Ehuang Bridge over

Yangtze RiverHubei Prov. 480 2003 Concrete

Beam

continue


18 Taoyaomen Bridge Zhejiang Prov. 580 2003 Hybrid Beam

19Donghai Bridge (Navigation Span) Shanghai 420 2005


203rd Nanjing Bridge over Yangtze River


Girder

continue


Span/mYr.of

Completion Type

16Junshan Bridge


Girder

17Ehuang Bridge over

Yangtze RiverHubei Prov. 480 2003 Concrete

Beam


18 Taoyaomen Bridge Zhejiang Prov. 580 2003 Hybrid Beam

19Donghai Bridge (Navigation Span) Shanghai 420 2005


203rd Nanjing Bridge over Yangtze River


Girder

continue


Span/mYr.of

Completion Type

21Anqing Bridge

over Yangtze River Anhui Prov. 510 2005 Steel Box Girder

22Runyang

Bridge(N) over Yangtze River


Girder


23Fengjie Bridge

over Yangtze River Chongqing 460 2006 Concrete Beam

24Zhanjiang Bay

Bridge Guangdong

Prov. 480 2006 Hybrid Beam

25Shibangou Bridge over Yangtze River Chongqing 450 2007 Concrete

Beam

continue


Span/mYr.of

Completion Type

26Hangzhou Bay

Bridge (Navigation Span)

Zhejiang Prov. 448 2007 Steel Box

Girder

27Kangjiatuo Bridge over Yangtze River Chongqing 460 2008 Concrete

Beam


28Yibin Bridge over Yangtze River

Sichuan Prov. 460 2008 Concrete

Beam

29Changshou Bridge over Yangtze River Chongqing 460 2008 Concrete

Beam

30Guanyinyan Bridge over Yangtze River Chongqing 436 2008


continue


Yr.ofCompletion

Type

31Sutong Bridge over Yangtze River


Girder

32 Jintang Bridge Zhejiang Prov. 620 2008 Steel Box

Girder


33Tianxingzhou Bridge over Yangtze River

Hubei Prov. 504 2008 Steel Truss

34 Stongcutters Birdge Hongkong 1018 2008 Hybrid Beam

35Shanghai Bridge over Yangtze River Shanghai 730 2010 Steel Box

Girder




Span/mYr.of

Completion Type

36 Minpu Bridge Shanghai 708 2010 Steel Truss

37Edong Bridge over Yangtze River

Hubei Prov. 926 2010 Hybrid

Beam

continue


38Jingyue Bridge

over Yangtze RiverHubei Prov. 816 2010 Hybrid

Beam

39 Ningbo Bridge Zhejiang Prov. 468 2011


40Erqi Bridge over Yangtze River

Hubei Prov. 616 2011 Hybrid

Beam

continue


Yr.ofCompletion

Type

412nd Hejiang Bridge over Yangtze River

Sichuan Prov. 420 2012 Concrete

Beam

42Xiangshan Port

Bridge Zhejiang Prov. 688 2012 Steel Box

Girder


43 Jiashao Bridge Zhejiang Prov. 428 2012 Steel Box

Girder

442nd Jiaojiang Bridge

Zhejiang Prov. 480 2013


45Xiazhang Bay

BridgeFujian Prov. 780 2013 Steel Box

Girder

continue


Yr.ofCompletion

Type

46Anqing railway Bridge over Yangtze River

Anhui Prov. 580 2013 Steel Truss

47DongshuimenBridge over Chongqing 445 2013 Steel Truss


Yangtze River

48Tongling highway and railway Bridge over Yangtze River

Anhui Prov. 630 2014 Steel Truss

49Gangzhuao

Bridge(QIngzhou Navigation Span)

Guangdong Prov. 458 2014 Steel Box

Girder

Major suspension bridges completed or under construction in China （L≥400m）


Span/mYr.of

Completion Type

1 Dazi Bridge Xizang Prov. 500 1984 Steel Truss

2Shantou Bay Bridge

Guangdong Prov 452 1995 Concrete

Beam


Bridge g Prov. Beam

3XIlin Bridge over Yangtze River

Hubei Prov. 900 1996 Steel Box

Girder

4Fengdu Bridge over

Yangtze River Chongqing 450 1996 Steel Truss

5 Tsingma Bridge Hongkong 1377 1997 Steel Box Girder

continue


Yr.ofCompletion

Type

6 Humen Bridge Guangdong Prov. 888 1997 Steel Box

Girder

7Jiangyin Bridge

over Yangtze RiverJiangsu Prov. 1385 1999 Steel Box

Girder


8 Haicang Bridge Fujian Prov. 648 2000 Steel Box

Girder

9 Egongyan Bridge Chongqing 600 2000 Steel Box Girder

10Yinchang Bridge over Yangtze River

Hubei Prov. 960 2001 Steel Box

Girder

continue


Span/mYr.of

Completion Type

11Zhongxian Bridge over Yangtze River Chongqing 560 2001 Steel Truss

122nd WanzhouBridge over Yangtze River

Chongqing 580 2004 Steel Truss


13Runyang Bridge(S) over Yangtze River


Girder

14Yangluo Bridge


Girder

15 Balinghe Bridge GuizhouProv. 1088 2007 Steel Truss



continue


Span/mYr.of

Completion Type

16 Xihoumen Bridge Zhejiang Prov. 1650 2008 Steel Box

Girder

17Huangpu Zhujiang

BridgeGuangdong Prov. 1108 2008 Steel Box

Girder


18 —— Huluhe Bridge ShanxiProv. 700 2008 Steel Box

Girder

19Yuzui Bridge over Yangtze River Chongqing 616 2008 Steel Box

Girder

20 Siduhe Bridge Hubei Prov. 900 2009 Steel Truss

continue


Span/mYr.of

Completion Type

21 Beipanjiang Bridge GuizhouProv. 636 2009 Steel Truss

22 Kanzhou Bridge Jiangxi Prov. 408 2010 Steel Box

Girder


23 Aizhai Bridge Hunan Prov. 1176 2011 Steel Truss

24 Shuangyong Bridge Guangxi Prov. 430 2011 Steel Box

Girder

25 —— Lishui Bridge Hunan Prov. 856 2012 Steel Truss


Yr.ofCompletion

Type

26Nanxi Bridge over Yangtze

River

Sichuan Prov. 820 2012 Steel Box

Girder

274th Nanjing Bridge over Yangtze River


Girder

continue


g

28Taizhou Bridge over Yangtze

River


Girder

29Maanshan Bridge over Yangtze River

Anhui Prov. 1080 2013 Steel Box Girder

Major arch bridges completed or under construction in China （L≥400m）


Yr.of Completion

Type

1Wanxian Bridge over Yangtze River Chongqing 420 1997

Reinforced Concrete

Arch ／Deck

2 Lupu Bridge Shanghai 550 2003Steel Box

Arch/through


h

3Wushan Bridge

over Yangtze River Chongqing 460 2004

Steel Tube Concrete Arch /half‐through

4 Xinguang Bridge Guangdong Prov. 428 2006

Steel Truss Arch/throug

h

5Caiyuanba Bridge over Yangtze River Chongqing 420 2006

Steel Truss Arch/throug

h

continue


Span/mYr.of

Completion Type

6Rongxi Zhijinghe

Bridge Hubei Prov. 430 2007Steel Tube

Concrete Arch /Deck

7Chaotianmen

Bridge over Yangtze River

Chongqing 552 2008 Steel Truss Arch/through

8 D i h B id Ch i 400 2008 Steel Truss


8 Daninghe Bridge Chongqing 400 2008 Arch／Deck

9 Yongjiang Bridge Zhejiang Prov. 450 2009

Steel Box Arch /half‐through

104th Xiangjiang

BridgeHunan Prov. 400 2011

Steel Tube Concrete Arch /through

111st Hejiang Bridge over Yangtze River

Sichuan Prov. 510 2012

Steel Tube Concrete Arch /through

Summary（2）

• Since 1990, China has built many long span (>400m) bridges–cable-stayed

38 + 11 (u.c.) =49, the longest: Sutong Bridge (1088m)

– suspension

22 + 7 (u.c.) =29, the longest: Xihoumen Bridge (1650m)

–arch


arch

9 + 2 (u.c.) =11, the longest: Chaotianmeng Bridge (552m)

• Maintenance Needs after Construction Boom- short coming of design codes;

- too fast construction speed;

- unexpected increasing of traffic demands.



Summary（2）(cont.)

• Operation conditions of bridges–corrosion and rupture of steel wires in stay cables, hangers and PC

tendons

–cracks of concrete structures

–deterioration of non-structural components (e.g. pavement)

–human errors ? accident


Broken stay cable due to corrosion of Haiyin Bridge (1995)

Fall down of Tian Zuang Tai Bridge due to broken of PC cables (2004)

Limin Sun, Tongji.Univ., China APSS2010

a) Cracks on top slab of box-girderb) Concrete expansion on tower wallCracks of concrete bridges

Pavement damage of Bridge (2003)

32

Ship Collision, Jiujiang BridgeG d (2007)


Guangdong (2007)

Construction or Design ? Fenghuang Bridge, Hunan (2007)

More than 60 people were killed 33

Bridge structural monitoring system


Outline

• SHM for long span bridges in China

• SHMS of Donghai Bridge- Donghai bridge and its SHMS- Monitoring data (1 year, 2007) - what we get- Performance diagnosis - how to use data


• Summary

35

Bridges with structural Health Monitoring Systems in China




continue


continue


continue


continue


continue


continue




SHMS for Bridges in China

• More than 100 large bridges have installed SHMS in China since 1999.

• The primary objectives of the SHMS: –To provide supports for maintenance during operation

–To obtain information of structural performance under extreme events for assessing structural safety


events, for assessing structural safety

–To validate design assumptions and design loads, and to provide data for consummating the design code

• The cost of a SHMS generally take about 0.25-2.0% of the total construction cost of a bridge.

55

SHM for Donghai Bridge

- Donghai bridge and its SHMS


- Monitoring data (1 year, 2007) - what we get

- Performance dignosis - how to use data

Donghai Bridge• Donghai bridge is a linkage

connecting Shanghai and Yangshan Island deep water Port. The linkage is about 32 km long and consists of 2 cable stayed bridges and a large number of spans of continuous and

simply supported bridges.

• The bridges have been completed and opened to traffics in 2005. The health monitoring system was

Shanghai

Port


health monitoring system was completed in Oct., 2006.

Port

SHMS for Donghai Bridge

• Donghai Bridge is the only way linking the port to Shanghai. It is a very important structure.

• Donghai Bridge is the first large scale cross-sea bridge project in China and it lies on soft clay. The bridge carries heavy container trucks. Therefore, the durability against ocean environment, the un-uniform settlement of foundation and


environment, the un uniform settlement of foundation and the fatigue of steel deck are seriously concerned.

• The structural health monitoring system for Donghai Bridge (SHMSDH) was designed to automatically collect the data of environment and structural response.

58

Monitored sectors

Bottomland area (70-50m continuous girder spans) Sub-navigation channel Bridge

(70+120+120+70m continuous girder spans)

5X60m continuous girder spans

Main-navigation channel Bridge (420m cable-stayed bridge)

Outline of monitored spans of Donghai Bridge

Luchao Port


Sub-navigation channel Bridge (80+140+140+80m continuous girder spans)

5X70m continuous girder spans

Sub-navigation channel Bridge (90+160+160+90m continuous beam spans)

Kezhushan Bridge(332m cable-stayed bridge)

Yangshan Port

Open air station to corruption

Monitored items

• Environment of bridge site including temperature, wind speed, earthquake, wave and scour;

• Static and dynamic response of bridge includingdeformations of towers of cable-stayed bridges, deflections of continuous girders, un-uniform settlements of foundations, di l t f d d i j i t


displacements of dampers and expension joints, strains of girders, vibration of girders and towers, tensions of stay cables;

• Durability of structure including fatigue of steel structures and chloride corrosion of concrete.

60



Primary sensor technologies used

• FBG sensors for strains and temperatures

• GPS for monitoring deformations

• Fatigue sensor for fatigue of bridge girders


• 478 sensors in total (169 for main-navigation channel bridge)

61

Evaluation systems

• On-line evaluationThe on-line evaluation system is an automatic system.

- The system can analyze the data than to judge preliminarily the safety of structure.

- The system is able to automatically make a decision of whether it is need to alarm the management authority and to immediately start the off-line evaluation system.


• Off-line evaluationThe off-line evaluation system will process some advantaged analysis, such as structural static analysis, mode analysis, correlated analysis between the bridge behaviors and environmental factors and so on.

The system needs massive structural analysis and judgments by expertsthen gives an comprehensive evaluation of structural condition.

63

Main features of SHMSDH


Accessible via internet

66 Limin Sun, Tongji.Univ., China APSS2010

The real-time signal data collecting system

67

Monitoring data – for evaluation under extreme loads

• Typhoon

• Earthquake

• Explosion


Explosion

• Ship collision

68

Ship collision

0 55

0.025mode4 before

Limin Sun, Tongji.Univ., China APSS2010(a) 船撞前后MAC(1,1)的比较

0 500 1000 1500 2000 2500 30000.95

0.96

0.97

0.98

0.99

1

A comparison between before and after collision

Time (min)

MA

C

MAC(2,2) beforeMAC(2,2) after

2007-01-01 00:00:00 2007-01-03 02:35:00

2007-01-0200:50:00~2007-01-0201:35:00

0 500 1000 1500 2000 2500 30000.975

0.98

0.985

0.99

0.995

1

Time (min)

MA

C

A comparison between before and after collision

MAC(1,1) beforeMAC(1,1) after

2007-01-01 00:00:00 2007-01-03 02:35:00

2007-01-0200:50:00~2007-01-0201:35:00

(b) 船撞前后MAC(2,2)的比较

0 500 1000 1500

0.4

0.45

0.5

0.55

Time (min)

Freq

uenc

y

(Hz)

mode1 beforemode1 aftermode2 beforemode2 aftere

2007-01-01 00:00:002007-01-02 01:35:00

2007-01-02 00:50:002007-01-03 02:35:00

0 500 1000 15000

0.005

0.01

0.015

0.02

Time (min)

Mod

al d

ampi

ng ra

tio

mode4 after

2007-01-01 00:00:002007-01-02 01:35:00

2007-01-02 00:50:002007-01-03 02:35:00

(a) 船撞前后模态频率的比较 (b) 船撞前后模态阻尼比的比较

69



Wenchuan Earthquake in 2008

Limin Sun, Tongji.Univ., China APSS2010 70 Limin Sun, Tongji.Univ., China APSS2010 71

Performance diagnosis


B o tto m la n d a r e a(7 0 -5 0 m c o n tin u o u s g ird e r sp a n s ) S u b -n a v ig a tio n c h a n n e l B r id g e

(7 0 + 1 2 0 + 1 2 0 + 7 0 m c o n tin u o u s g ird e r sp a n s )

5 X 6 0 m c o n tin u o u s g ird e r sp a n s

M a in -n a v ig a tio n c h a n n e l B r id g e (4 2 0 m c a b le -s ta y e d b r id g e )

O u tlin e o f m o n ito re d s p a n s o f D o n g h a i B r id g e

L u c h a o P o r t

Performance diagnosis of Donghai Bridge


S u b -n a v ig a tio n c h a n n e l B r id g e (8 0 + 1 4 0 + 1 4 0 + 8 0 m c o n tin u o u s g ird e r sp a n s )

5 X 7 0 m c o n tin u o u s g ir d e r s p a n s

S u b -n a v ig a tio n c h a n n e l B r id g e (9 0 + 1 6 0 + 1 6 0 + 9 0 m c o n tin u o u s b e a m sp a n s )

K e z h u s h a n B r id g e(3 3 2 m c a b le -s ta y e d b r id g e )

Ya n g sh a n P o r t

O p e n a ir s ta tio n to c o r r u p tio n

73


Type of sensor Quantity Measurement Location 1 air temperature(At) Deck 24 steel temperature(St) Deck

Thermometer Thermometer Thermometer 20 concrete temperature(Ct) Deck/Tower Anemometer 1 wind speed/direction(Ane) Tower Weather station 1 wind speed/direction, humidity(Aws) Deck GPS 3 displacement Tower/Deck

36 steel dynamic strain Deck FBG strain sensor FBG strain sensor 12 concrete dynamic strain Tower/Deck

19 acceleration Deck Accelerometer Accelerometer 8 acceleration Tower Fatigue sensor 24 Deck Extensometer 4 displacement Expansion joint Cable force sensor 8 cable force(Cf) Cable Displacement sensor 2 displacement Deck

169 sensors

74

Data analysis – how to make use of the data measured ?

Sensitive parameter related to damageglobal vs. local

in this study, vibration-based parameter (frequency)

Parameter variationdue to damage (or boundary condition)


due to damage (or boundary condition)+ environmental effects (temp., traffic)

Uncertainty of parametersstatistic method, based on long term data

75



Is it possible to separate?

Total response of structure measured

Data analysis – prepare for damage identification ?


Response due to environment change

Response due to structural damage

76

Environmental factors - Temperature

0 60 120 180 240 300 3600

10

20

30

40

tem

pera

ture

(0 C

) Air Temp. Data in 2007


0 60 120 180 240 300 360

time (d)

0 60 120 180 240 300 3600

10

20

30

40

tem

pera

ture

(0 C

)

time (d)

0 60 120 180 240 300 3600

10

20

30

40

tem

pera

ture

(0 C

)

time (d)

Concrete Temp.

Steel Temp.

77

Environmental factors - Traffic

2

3

4

rms

(gal

)

Vertical acc. RMS-> equivalent traffic load


0 60 120 180 240 300 3600

1

time (d)

Chinese NewyearMayday GW

National Day GW

79

3rd modal freq. vs. Temp.

Temp3rd freq


PSD of Freq. and Temp.

Temp3rd freq7th freq


Correlation between Freq. and Temp.




Displ. at expansion joint and Temp.


Experimental validation


Experimental validation

19.5

20.0

20.5

cy (H

z)


-10 0 10 20 30 4018.0

18.5

19.0

frequ

enc

temperature (0C)

86

Correlation coef. of 1st freq

cycle (h)

air temperature

vertical acc. RMS

wind speed

wind direction

humidity

6 0.807 0.891 0.168 0.068 0.038

8 0.323 0.691 0.092 0.093 0.211

12 0.732 0.915 0.472 0.491 0.359

24 0.409 0.476 0.406 0.164 0.109


24 0.409 0.476 0.406 0.164 0.109

28 0.027 0.969 0.026 0.132 0.002

33.6 0.181 0.949 0.026 0.182 0.172

42 0.098 0.796 0.063 0.583 0.058

56 0.017 0.684 0.148 0.252 0.060

84 0.038 0.924 0.119 0.074 0.372

168 0.541 0.950 0.053 0.033 0.310

87

Estimation of effects by temp. and vibration level

0 1 2Y Tβ β β θ ε= + + +

Y : structural frequencyT : air temperature

θ: structural vibration level (traffic)


θ: structural vibration level (traffic)ε : remainb : coefficient fitted based on the measurement (1 year)

88

Alarm at abnormal structural conditions

boundary condition changes

Y


typhoon

0 60 120 180 240 300 360-0.008

-0.006

-0.004

-0.002

0.000

0.002

0.004

0.006

0.008 99% 99.9%

resi

dual

freq

uenc

y (H

z)

time (d)

ε

89



• More than 100 large bridges have installed a SHMS in China. Generally, the cost of a SHMS will take about 0.25-2.0% of the total of construction of a bridge.

• SHM for Donghai Bridge was introduced. The response data during typhoon, earthquake, explosion and ship collision were automatically collected for rapid evaluation.

Summary（3）


were automatically collected for rapid evaluation.

• Based on long term monitoring data, it is possible to distinguish the structural response induced by temperature change (wind & traffic?) from the entire response. This may improve the feasibility of damage identification by using statistic methods.

90

Consideration on design of SHM system


- based on Vulnerability Analysis

Outline

• Background

• Two-parameters structural vulnerability

analysis method

• Applications in SHM system design


pp y g

• Case studies

• Summary

92

Background

• SHM system design:– two of the most important tasks:

allocation of sensors (where and what?), alarming algorithm

– semi-empirical; not optimized;

• Vulnerability:

– regarded as structural performance susceptibility to local damage of


structure;

–depends on element strength, system (topology), loads, failure mode, etc.

• Research purpose:–propose concepts and methods of structural vulnerability analysis;

– find the most vulnerable components which are need to be monitored and corresponding alarming threshold once damages occur.

93

Two-parameters structural vulnerability analysis

• Damage process of structural system


Two-parameters structural vulnerability analysis(cont.)

• Concepts and definitions proposed in order to assess structural vulnerability quantitatively:–Damage Event: exterior disturbance causing damages of structural

system

–Damage Scenario: set of damaged structural components

–Damage Consequence: degradation severity of structural performance after being damaged


performance after being damaged

–Failure Path: series of components causing failure of whole structural system

–Failure Scenario: set of components causing failure of whole structural system

–Robustness: ability to maintain original structural performance after being damaged

–Vulnerability: sensitivity of structural performance to local damages

–Vulnerable Scenario: failure scenario with relatively higher vulnerability

95



Two-parameters structural vulnerability analysis (cont.)

• CI is the influence degree of damage scenario to structural performance.

h P l fPPPCI DS

DS−

=


where P: structural performance

• MI is the proportion of the damage scenario to the overall structural system.

MI --- the severity of a specified damage scenario MI∈[0,1]

96



• (a) The structural vulnerability assessment in various damage severities for a given damage scenario.

• (b) The structural vulnerability assessment in various damage scenarios.

97


1)(0)(),(

1

21

≤≤=

DSFDSFDSFFMinimize

Pareto optimization


1)(0 2 ≤≤ DSF

where F1(DS)=1-CIDS，F2(DS)=MIDS.

98

Applications in SHM system

Application of vulnerability analysis in allocation of sensors


Applications in SHM system (cont.)

Application of vulnerability analysis in early alarming system


Cable-stayed bridge (half model)

Case study


Damage scenario: cable breakageStructural performance: (1) maximum stress; (2) girder buckling

101



Case study (cont.)

The variation of structural performance to different damage scenarios


buckling

103

Case study (cont.)

Pareto frontier maximum stress


Case study (cont.)

Pareto frontier buckling


Case study (cont.)

Cables need to be monitored (circled)


Summary(4)

• This study investigated the quantitative analysis method of structural vulnerability and its application in bridge SHM system.

• The proposed two-parameters structural vulnerability analysis method is based on the influence magnitude of damage scenario to structural performance and the proportion of the damage scenario in the overall


proportion of the damage scenario in the overall structural system.

• The structural vulnerability analysis results may be employed as a reference for designing sensors allocation and alarming threshold of bridge SHM system.

107

Thanks !&

Questions ?


AcknowledgementThis research was supported by the key program of NSFC (Grant No. 50538020) and the key research project of Chinese State Key Laboratory for Disaster Reduction in Civil Engineering (Grant No. SLDRCE08-A-05).

Co-researchers:Dr. Danhui Dan, Dr. Zhi Sun, Dr. Hongwei HuangDr. Zhihua Min, Dr. Gang YuHaishan Wu, Yi Zhou, Meiju Jiao, Shouwang Sun, Xueliang Li

108

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