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
Limin Sun, Tongji.Univ., China APSS2010 2
–Case study –SHM for Donghai Bridge
–Performance diagnosis
–Consideration on design of SHM system
Chinese historic bridges
Limin Sun, Tongji.Univ., China APSS2010 3
Chinese historic bridges
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Zhaozhou Bridge (BC605), Hebei
Step Bridge, Zhejiang
Pingan Bridge (BC1152), Fujian
Chinese historic bridges (cont.)
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Luding Bridge (BC1702), Sichuan
Chinese historic bridges (cont.)
Lounge Bridge ZhejiangHong Bridge Henan
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Chengyang Bridge (BC1924), Guangxi
Lounge Bridge, ZhejiangHong Bridge, Henan
APSS2010, 2 Aug., Tokyo
Limin Sun, Tongji Univ. 2
Chinese historic bridges (cont.)
Qiantang River Bridge
Limin Sun, Tongji.Univ., China APSS2010 7
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?
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• Durability–stone > wood >? iron & steel, concrete
Chinese modern bridges
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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
Limin Sun, Tongji.Univ., China APSS2010 11
3 Yangpu Bridge Shanghai 602 1993
Steel‐concrete Composed Beam
4Tongling Bridge over Yangtze
River
Anhui Prov. 432 1995 Concrete
Beam
52nd Wuhan Bridge over Yangtze
River
Hubei Prov. 400 1995 Concrete
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
Limin Sun, Tongji.Univ., China APSS2010 12
8 Ting Kau Bridge Hongkong 475 1997
Steel‐concrete Composed Beam
9Kap Shui Mun
Bridge Hongkong 430 1997 Hybrid Beam
10Shantou Queshi
BirdgeGuangdong Prov. 518 1998 Hybrid Beam
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Limin Sun, Tongji Univ. 3
continue
NO. Pictures Name LocationMain
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
Limin Sun, Tongji.Univ., China APSS2010 13
Beam
132nd Nanjing Bridge over Yangtze River
Jiangsu Prov. 628 2001 Steel Box
Girder
14Jingzhou Bridge over Yangtze River
Hubei Prov. 500 2002 Concrete
Beam
15Dafosi Bridge over Yangtze River Chongqing 450 2002 Concrete
Beam
NO. Pictures Name LocationMain
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
Limin Sun, Tongji.Univ., China APSS2010 14
18 Taoyaomen Bridge Zhejiang Prov. 580 2003 Hybrid Beam
19Donghai Bridge (Navigation Span) Shanghai 420 2005
Steel‐concrete Composed Beam
203rd Nanjing Bridge over Yangtze River
Jiangsu Prov. 648 2005 Steel Box
Girder
continue
NO. Pictures Name LocationMain
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
Limin Sun, Tongji.Univ., China APSS2010 15
18 Taoyaomen Bridge Zhejiang Prov. 580 2003 Hybrid Beam
19Donghai Bridge (Navigation Span) Shanghai 420 2005
Steel‐concrete Composed Beam
203rd Nanjing Bridge over Yangtze River
Jiangsu Prov. 648 2005 Steel Box
Girder
continue
NO. Pictures Name LocationMain
Span/mYr.of
Completion Type
21Anqing Bridge
over Yangtze River Anhui Prov. 510 2005 Steel Box Girder
22Runyang
Bridge(N) over Yangtze River
Jiangsu Prov. 406 2005 Steel Box
Girder
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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
NO. Pictures Name LocationMain
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
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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
Steel‐concrete Composed Beam
continue
NO. Pictures Name Location Main Span/m
Yr.ofCompletion
Type
31Sutong Bridge over Yangtze River
Jiangsu Prov. 1088 2008 Steel Box
Girder
32 Jintang Bridge Zhejiang Prov. 620 2008 Steel Box
Girder
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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
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Limin Sun, Tongji Univ. 4
NO. Pictures Name LocationMain
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
Limin Sun, Tongji.Univ., China APSS2010 19
38Jingyue Bridge
over Yangtze RiverHubei Prov. 816 2010 Hybrid
Beam
39 Ningbo Bridge Zhejiang Prov. 468 2011
Steel‐concrete Composed Beam
40Erqi Bridge over Yangtze River
Hubei Prov. 616 2011 Hybrid
Beam
continue
NO. Pictures Name Location Main Span/m
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
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43 Jiashao Bridge Zhejiang Prov. 428 2012 Steel Box
Girder
442nd Jiaojiang Bridge
Zhejiang Prov. 480 2013
Steel‐concrete Composed Beam
45Xiazhang Bay
BridgeFujian Prov. 780 2013 Steel Box
Girder
continue
NO. Pictures Name Location Main Span/m
Yr.ofCompletion
Type
46Anqing railway Bridge over Yangtze River
Anhui Prov. 580 2013 Steel Truss
47DongshuimenBridge over Chongqing 445 2013 Steel Truss
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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)
NO. Pictures Name LocationMain
Span/mYr.of
Completion Type
1 Dazi Bridge Xizang Prov. 500 1984 Steel Truss
2Shantou Bay Bridge
Guangdong Prov 452 1995 Concrete
Beam
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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
NO. Pictures Name Location Main Span/m
Yr.ofCompletion
Type
6 Humen Bridge Guangdong Prov. 888 1997 Steel Box
Girder
7Jiangyin Bridge
over Yangtze RiverJiangsu Prov. 1385 1999 Steel Box
Girder
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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
NO. Pictures Name LocationMain
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
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13Runyang Bridge(S) over Yangtze River
Jiangsu Prov. 1490 2005 Steel Box
Girder
14Yangluo Bridge
over Yangtze RiverHubei Prov. 1280 2007 Steel Box
Girder
15 Balinghe Bridge GuizhouProv. 1088 2007 Steel Truss
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Limin Sun, Tongji Univ. 5
continue
NO. Pictures Name LocationMain
Span/mYr.of
Completion Type
16 Xihoumen Bridge Zhejiang Prov. 1650 2008 Steel Box
Girder
17Huangpu Zhujiang
BridgeGuangdong Prov. 1108 2008 Steel Box
Girder
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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
NO. Pictures Name LocationMain
Span/mYr.of
Completion Type
21 Beipanjiang Bridge GuizhouProv. 636 2009 Steel Truss
22 Kanzhou Bridge Jiangxi Prov. 408 2010 Steel Box
Girder
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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
NO. Pictures Name Location Main Span/m
Yr.ofCompletion
Type
26Nanxi Bridge over Yangtze
River
Sichuan Prov. 820 2012 Steel Box
Girder
274th Nanjing Bridge over Yangtze River
Jiangsu Prov. 1418 2013 Steel Box
Girder
continue
Limin Sun, Tongji.Univ., China APSS2010 27
g
28Taizhou Bridge over Yangtze
River
Jiangsu Prov. 1080 2013 Steel Box
Girder
29Maanshan Bridge over Yangtze River
Anhui Prov. 1080 2013 Steel Box Girder
Major arch bridges completed or under construction in China (L≥400m)
NO. Pictures Name Location Main Span/m
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
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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
NO. Pictures Name LocationMain
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
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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
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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.
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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
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Broken stay cable due to corrosion of Haiyin Bridge (1995)
Fall down of Tian Zuang Tai Bridge due to broken of PC cables (2004)
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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)
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Guangdong (2007)
Construction or Design ? Fenghuang Bridge, Hunan (2007)
More than 60 people were killed 33
Bridge structural monitoring system
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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
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• Summary
35
Bridges with structural Health Monitoring Systems in China
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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
Limin Sun, Tongji.Univ., China APSS2010
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
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- 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
Limin Sun, Tongji.Univ., China APSS2010
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
Limin Sun, Tongji.Univ., China APSS2010
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
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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
Limin Sun, Tongji.Univ., China APSS2010
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
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Primary sensor technologies used
• FBG sensors for strains and temperatures
• GPS for monitoring deformations
• Fatigue sensor for fatigue of bridge girders
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• 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.
Limin Sun, Tongji.Univ., China APSS2010
• 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
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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
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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
APSS2010, 2 Aug., Tokyo
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Wenchuan Earthquake in 2008
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Performance diagnosis
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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
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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
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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)
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due to damage (or boundary condition)+ environmental effects (temp., traffic)
Uncertainty of parametersstatistic method, based on long term data
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Is it possible to separate?
Total response of structure measured
Data analysis – prepare for damage identification ?
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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
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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
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0 60 120 180 240 300 3600
1
time (d)
Chinese NewyearMayday GW
National Day GW
79
3rd modal freq. vs. Temp.
Temp3rd freq
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PSD of Freq. and Temp.
Temp3rd freq7th freq
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Correlation between Freq. and Temp.
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Displ. at expansion joint and Temp.
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Experimental validation
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Experimental validation
19.5
20.0
20.5
cy (H
z)
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-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
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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
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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)
Limin Sun, Tongji.Univ., China APSS2010
θ: structural vibration level (traffic)ε : remainb : coefficient fitted based on the measurement (1 year)
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Alarm at abnormal structural conditions
boundary condition changes
Y
Limin Sun, Tongji.Univ., China APSS2010
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
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APSS2010, 2 Aug., Tokyo
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• 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)
Limin Sun, Tongji.Univ., China APSS2010
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.
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Consideration on design of SHM system
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- based on Vulnerability Analysis
Outline
• Background
• Two-parameters structural vulnerability
analysis method
• Applications in SHM system design
Limin Sun, Tongji.Univ., China APSS2010
pp y g
• Case studies
• Summary
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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
Limin Sun, Tongji.Univ., China APSS2010
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.
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Two-parameters structural vulnerability analysis
• Damage process of structural system
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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
Limin Sun, Tongji.Univ., China APSS2010
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
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APSS2010, 2 Aug., Tokyo
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Two-parameters structural vulnerability analysis (cont.)
• CI is the influence degree of damage scenario to structural performance.
h P l fPPPCI DS
DS−
=
Limin Sun, Tongji.Univ., China APSS2010
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]
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Two-parameters structural vulnerability analysis (cont.)
Limin Sun, Tongji.Univ., China APSS2010
• (a) The structural vulnerability assessment in various damage severities for a given damage scenario.
• (b) The structural vulnerability assessment in various damage scenarios.
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Two-parameters structural vulnerability analysis (cont.)
1)(0)(),(
1
21
≤≤=
DSFDSFDSFFMinimize
Pareto optimization
Limin Sun, Tongji.Univ., China APSS2010
1)(0 2 ≤≤ DSF
where F1(DS)=1-CIDS,F2(DS)=MIDS.
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Applications in SHM system
Application of vulnerability analysis in allocation of sensors
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Applications in SHM system (cont.)
Application of vulnerability analysis in early alarming system
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Cable-stayed bridge (half model)
Case study
Limin Sun, Tongji.Univ., China APSS2010
Damage scenario: cable breakageStructural performance: (1) maximum stress; (2) girder buckling
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APSS2010, 2 Aug., Tokyo
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Case study (cont.)
The variation of structural performance to different damage scenarios
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buckling
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Case study (cont.)
Pareto frontier maximum stress
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Case study (cont.)
Pareto frontier buckling
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Case study (cont.)
Cables need to be monitored (circled)
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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
Limin Sun, Tongji.Univ., China APSS2010
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.
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Thanks !&
Questions ?
Limin Sun, Tongji.Univ., China APSS2010
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
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