1. Traffic Infrastructure Developmentthost-iabse-elearning.org/l8/data/downloads/handouts 4 per page.pdf · Suspension bridge: 1490m (Runyang Bridge, 3rdrd longest in the world)longest

YaoYao--Jun GE & HaiJun GE & Hai--Fan XIANGFan XIANG

Tongji UniversityTongji University

Shanghai ChinaShanghai China

Keynote Lecture - IABSE Conference - Weimar 2007

Great Demand and Various Challenges Yao-Jun GE & Hai-Fan XIANG 2

OVERVIEWOVERVIEWOVERVIEW1.1. Traffic Infrastructure DevelopmentTraffic Infrastructure Development

2.2. Improvement Plan of Traffic InfrastructureImprovement Plan of Traffic Infrastructure

3.3. Aerodynamic Challenge on Suspension BridgesAerodynamic Challenge on Suspension Bridges

4.4. Bridging Capacity Challenge on Other BridgesBridging Capacity Challenge on Other Bridges

5.5. Technical Challenge on Twin Spans or DecksTechnical Challenge on Twin Spans or Decks

6.6. ConclusionsConclusions


1. Traffic Infrastructure Development

Ancient TimeAncient Time5000 years human history5000 years human history

Thousands of bridgesThousands of bridges

Iron chain suspension bridge (completed in 400 AD)

Zhaozhou stone arch bridge (completed in 605 AD)


1. Traffic Infrastructure Development (Cont’d)

Last Three Decades in EconomyLast Three Decades in EconomyNew reform and open policy since 1978New reform and open policy since 1978Soaring of ChinaSoaring of China’’s economys economy

1978 1980 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 20040

5000

10000

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Ann

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GDP in 1978: 365 billion Chinese yuanGDP in 2005: 18,396 billion Chinese yuanGreat Demand on Traffic Infrastructure Development

50 times increase



Last Two Decades in Highway DevelopmentLast Two Decades in Highway DevelopmentThe first expressway completed in 1988The first expressway completed in 1988Rapid development of expressway for two decadesRapid development of expressway for two decades

Expressway and total highway in 1988: 147 km and 1.0 million kmExpressway and total highway in 2005: 41,005 km and 1.9 million kmThe National Trunk Highway System will be built by 2008

147 271 522 574 652 11451603 2141

34224771

873311605

1631419437

25130

29745

34288

41005

1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 20060

10000

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essw

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ileag

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Highway Bridge DevelopmentHighway Bridge DevelopmentThe total linear length: The total linear length: 3,3903,390 km (1988) km (1988) 14,75014,750 km (2005)km (2005)The total number: The total number: 124,200124,200 (1988) (1988) 336,600336,600 (2005)(2005)Number of longNumber of long--span bridges over 400m: span bridges over 400m: 3838 (2005)(2005)

Suspension bridges: 13Suspension bridges: 13CableCable--stayed bridges: 22stayed bridges: 22Arch bridges: 3Arch bridges: 3

Span length records of major bridgesSpan length records of major bridgesSuspension bridge: 1490m (Runyang Bridge, 3Suspension bridge: 1490m (Runyang Bridge, 3rdrd longest in the world)longest in the world)CableCable--stayed bridge: 648m (3stayed bridge: 648m (3rdrd Nanjing Bridge, 3Nanjing Bridge, 3rdrd longest in the world)longest in the world)Steel arch bridge: 550m (Lupu Bridge, the longest in the wSteel arch bridge: 550m (Lupu Bridge, the longest in the world)orld)Concrete arch bridge:420m (Wanxian Bridge, the longest in the woConcrete arch bridge:420m (Wanxian Bridge, the longest in the world)rld)


Completed Major Bridges with a Main Spain over 400mType No Bridge Name Main Span Year Built No Bridge Name Main Span Year Built

1 Tibet Dazi 500m 1984 8 Jiangsu Jiangyin 1385m 19992 Shantou Bay 452m 1995 9 Sichuan Egongyan 600m 20003 Hubei Xiling 900m 1996 10 Sichuan Zhongxian 560m 20014 Sichuan Fengdu 450m 1997 11 Hubei Yicang 960m 20015 Guangdong Humen 888m 1997 12 2nd Sichuan Wanxian 580m 20046 Hongkong Tsingma 1377m 1997 13 Jiangsu Runyang S. 1490m 20057 Xiamen Haicang 648m 19991 Shanghai Nanpu 423m 1991 12 Chongqing Dafosi 450m 20012 Hubei Yunyan 414m 1993 13 2nd Jiangsu Nanjing 628m 20013 Shanghai Yangpu 602m 1993 14 Hubei Junshan 460m 20024 Anhui Tongling 432m 1995 15 Hubei Jingzhou 500m 20025 2nd Hubei Wuhan 400m 1995 16 Hubei Ehuang 480m 20026 Chongqing Lijiatuo 444m 1996 17 Zhejian Taoyaomen 580m 20037 Shanghai Xupu 590m 1997 18 Fujian Qingzhou 605m 20038 H.K. Kap Shui Mun 430m 1997 19 Anhui Anqing 510m 20049 Hong Kong Tingkau 475m 1998 20 East Sea Main Bridge 420m 200510 Hubei Queshi 518m 1999 21 3rd Jiangsu Nanjing 648m 200511 Hubei Baishazhou 618m 2000 22 Jiangsu Runyang N. 406m 20051 Shanghai Lupu 550m 2003 3 Sichuan Wanxian 420m 20012 Sichuan Wushan 460m 2005

Susp

ensi

onC

able

-Sta

yed

Arch

3rd Nanjing Bridge (648m)

Wanxian Bridge (420m)

Lupu Bridge (550m)

Runyang Bridge (1490m)


2. Improvement Plan of Traffic Infrastructure

NationalNational ExpresswayExpressway NetworkNetwork PlanPlan (2004(2004--2020)2020)IndependentIndependent expresswayexpressway systemsystem

ConnectingConnecting allall thethe citiescities withwith overover 200,000200,000 populationpopulation (total(total oneone billion)billion)CoveringCovering thethe territoryterritory contributedcontributed toto 85%85% GDPGDP

““79187918”” NetworkNetwork systemsystem (34(34 routes)routes)77 RadiatingRadiating routesroutes centeredcentered inin BeijingBeijing－－brownbrown lineslines99 NorthNorth--southsouth routesroutes－－greengreen lineslines1818 EastEast--westwest routesroutes－－blueblue lineslines

TotalTotal lengthlength ofof thethe networknetwork29,00029,000 kmkm completedcompleted

TotalTotal length:length: 85,00085,000 kmkm 16,00016,000 kmkm underunder constructionconstruction40,00040,000 kmkm toto bebe builtbuilt (from(from 2005)2005)


2. Improvement Plan of Traffic Infrastructure (Cont’d)

National Expressway Network Plan National Expressway Network Plan (2004(2004--2020)2020)


2. Improvement Plan of Traffic Infrastructure (Cont’d)Financing Analysis of Traffic InfrastructureFinancing Analysis of Traffic Infrastructure

Investment component in 2005 (6 sectors)Investment component in 2005 (6 sectors)

Loans and bonds: 82.6% Loans and bonds: 82.6% (43.1+38.2+1.3)(43.1+38.2+1.3)

Vehicle purchase tax: 10.3%Vehicle purchase tax: 10.3%

Government grants: 7.1% Government grants: 7.1% (4.7+2.4)(4.7+2.4)

Toll road policyToll road policy

The 82.6% investment will be refunded by The 82.6% investment will be refunded by ““toll roadtoll road””

Almost all new roads, bridges and tunnels are Almost all new roads, bridges and tunnels are ““toll roadtoll road””

The length of The length of ““tolltoll--roadroad”” is about 10% in total highway mileagesis about 10% in total highway mileages

Domestic loans

Local government

Vehicle purchase tax

Rest investment: 4.7%

Central government: 2.4%Foreign loans: 1.3%

43.1%

38.2%

10.3%


2. Improvement Plan of Traffic Infrastructure (Cont’d)

LongLong--Span Bridges under ConstructionSpan Bridges under ConstructionNumber of longNumber of long--span bridges over 400m: 26 (2007)span bridges over 400m: 26 (2007)

Suspension bridges: Suspension bridges: 99CableCable--stayed bridges: 13stayed bridges: 13Arch bridges: 4Arch bridges: 4

Span length records of major bridgesSpan length records of major bridgesSuspension bridge: 1650m (Xihoumen Bridge, 2nd longest in the woSuspension bridge: 1650m (Xihoumen Bridge, 2nd longest in the world)rld)CableCable--stayed bridge: 1088m (Sutong Bridge, the longest in the world)stayed bridge: 1088m (Sutong Bridge, the longest in the world)Steel arch bridge: 552m (Caotianmen Bridge, the longest in the wSteel arch bridge: 552m (Caotianmen Bridge, the longest in the world)orld)DoubleDouble--span suspension bridge: 2span suspension bridge: 2××10801080m (Taizhou Bridge)m (Taizhou Bridge)TwinTwin--deck cabledeck cable--stayed bridge: 468m stayed bridge: 468m ×× 2 (Ningbo Bridge)2 (Ningbo Bridge)


2. Improvement Plan of Traffic Infrastructure (Cont’d)LongLong--span Bridges under Construction: 26span Bridges under Construction: 26

Type No Bridge Name Main Span Year Built No Bridge Name Main Span Year Built1 Zhejiang Xihoumen 1650m 2008 6 Guizhou Balinghe 1088m 20092 4th Jiangsu Nanjing 1418m 2010 7 Jiangsu Taizhou 2×1080m 20103 Hubei Yangluo 1280m 2007 8 Anhui Maanshan 2×1000m 20104 Hunan Aizhai 1146m 2009 9 Guizhou Beipanjiang 888m 20095 Guangdong Huangpu 1108m 20081 Jiangsu Sutong 1088m 2008 8 Zhoushan Jintang 620m 20082 H.K. Stonecutters 1018m 2009 9 Wuhan Tianxinzhou 504m 20083 Hubei Edong 926m 2009 10 Zhanjiang Bay 480m 20074 Hubei Jingsha 816m 2009 11 Zhejiang Ningbo 464m×2 20105 Shanghai Yangtze 730m 2009 12 Sichuan Fuling 450m 20086 Shanghai Minpu 708m 2009 13 Hangzhou Bay 448m 20087 Zhejiang Xiangshan 688m 20091 Chongqin Caotianmen 552m 2009 3 Chongqing Caiyuanba 420m 20082 Guangdong Xinguang 428m 2008 4 4th Hunan Xiantan 400m 2007

Susp

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onCa

ble-

Stay

ed

Arch

Taizhou Bridge (2×1080m) Ningbo Bridge (468m×2)

2. Improvement Plan of Traffic Infrastructure (Cont’d)Major Bridges with Various Challenges: 8Major Bridges with Various Challenges: 8

Xihoumen Bridge (1650m)

Sutong Bridge (1088m) Stonecutter Bridge (1018m) Edong Bridge (926m) Chaotianmen Bridge (552m))

Runyang Bridge (1490m)


3. Aerodynamic Challenge on Suspension Bridges

RunyangRunyang Suspension BridgeSuspension Bridge

Span arrangementSpan arrangement

Central span: 1490m (AK 1991m and GB 1624m)

Deck cross sectionDeck cross section

Box girder depth: 3m (GB 4.0m and XB 3.5m)Great Demand and Various Challenges

Yao-Jun GE & Hai-Fan XIANG 16

3. Aerodynamic Challenge on Suspension Bridges (Cont’d)

RunyangRunyang Suspension Bridge Suspension Bridge (Cont(Cont’’d)d)Fundamental natural frequenciesFundamental natural frequencies

Symmetric Antisymm. Symmetric Antisymm. Symmetric Antisymm.Runyang 1490 0.0489 0.1229 0.1241 0.0884 0.2308 0.2698

Great Belt 1624 0.0521 0.118 0.0839 0.0998 0.278 0.383Xihoumen 1650 0.0484 0.1086 0.1 0.0791 0.2323 0.238

BridgeName

Lateral Frequency (Hz) Vertical Frequency (Hz) Torsional Frequency (Hz)Span(m)

Bending frequencies are quite reasonable compared with the other two.

Torsional frequencies are relative lower due to shallow depth of the box.



RunyangRunyang Suspension Bridge Suspension Bridge (Cont(Cont’’d)d)Investigation of aerodynamic instabilityInvestigation of aerodynamic instability

Box girder with central stabilizerBox girder with central stabilizer

Sectional Model Full ModelOriginal box girder 50.8 52.5

Box girder with 0.65m stabilizer 58.1 53.8Box girder with 0.88m stabilizer 64.9 55.1Box girder with 1.1m stabilizer 67.4 56.4

54

Minimum flutter speed (m/s) Required(m/s)Deck Box Girder Configuration

Central stabilizerCentral stabilizer



XihoumenXihoumen Suspension BridgeSuspension BridgeZhoushanZhoushan IslandIsland——Mainland Connection ProjectMainland Connection Project

Island connection: Jintang Island & Cezi IslandLong span length: required by deep water rather than navigation

XihoumenChannel

JintangIsland

CeziIsland



XihoumenXihoumen Suspension Bridge Suspension Bridge (Cont(Cont’’d)d)Span arrangementSpan arrangement

Bridge route: Cezi Tiger JintangCentral span: L = 1310m water depth = 35m

L = 1520m water depth = 20mL = 1650m water depth =＋0m

165015201310

Cezi Tiger Jintang



XihoumenXihoumen Suspension Bridge Suspension Bridge (Cont(Cont’’d)d)Box girder selection based on aerodynamic flutterBox girder selection based on aerodynamic flutter

RunyangRunyang Suspension Bridge: L=1490 m Suspension Bridge: L=1490 m UUcrcr= 52 = 52 m/sm/sGreat Belt Suspension Bridge: L=1624 m Great Belt Suspension Bridge: L=1624 m UUcrcr= 65 = 65 m/sm/sXihoumenXihoumen Suspension Bridge: L=1650 m Suspension Bridge: L=1650 m UUcrcr>78.4m/s?>78.4m/s?

Single box with a stabilizer Twin boxes with a sloth = 1.2m, 1.7m and 2.2m b = 6m and 10.6m



XihoumenXihoumen Suspension Bridge Suspension Bridge (Cont(Cont’’d)d)Experimental results of flutter speedsExperimental results of flutter speeds

Final scheme

−3° 0° +3° MinimumSingle box girder 50.7 46.2 48.7 46.2 78.4

Single box with a 1.2m stabilizer >89.3 >89.3 37.7 37.7 78.4Single box with a 1.7m stabilizer 88 >89.3 43.4 43.4 78.4Single box with a 2.2m stabilizer >89.3 >89.3 88 88 78.4

Twin boxes with a 6m slot 88.4 >89.3 >89.3 88.4 78.4Twin boxes with a 10.6m slot >89.3 >89.3 >89.3 >89.3 78.4

Critical flutter speed (m/s)Deck Box Girder Configuration Required(m/s)



5000m Spanned Suspension Bridge5000m Spanned Suspension BridgeConceptual design schemeConceptual design scheme

Span arrangement: 1,600m + 5,000m + 1,6000mSpan arrangement: 1,600m + 5,000m + 1,6000m

Twin box girdersWS: Bt=80m & D=40m NS: Bt=50m & D=14mWithout any stabilizer With vertical and horizontal ones

5000 16001600

f



5000m5000m SpannedSpanned SuspensionSuspension BridgeBridge (Cont(Cont’’d)d)AerodynamicAerodynamic stabilitystability analysisanalysis

CriticalCritical speedsspeeds forfor flutterflutter instabilityinstability andand torsionaltorsional divergencedivergence

PreliminaryPreliminary concludingconcluding remarksremarksTheseThese twotwo twintwin--boxbox crosscross sectionssections cancan meetmeet withwith thethe aerodynamicaerodynamicrequirementrequirement forfor mostmost typhoontyphoon--proneprone areasareas inin thethe world.world.

WS NS WS NS WS NS WS NSn = 1/8 0.9595 0.0594 0.0709 0.0907 82.9 74.7 90 120n = 1/9 0.06136 0.0612 0.0721 0.0893 88.8 77.4 96 124

n = 1/10 0.0623 0.06204 0.0727 0.0865 90.9 78.9 102 129n = 1/11 0.0624 0.0622 0.0727 0.0840 98.9 82.7 110 135

Utd (m/s)Ratiosag to span

fn(Hz) fα(Hz) Ufi (m/s)


4. Bridging Capacity Challenge on Other Bridges

SutongSutong CableCable--Stayed BridgeStayed BridgeGeneral arrangementGeneral arrangement

Span arrangement: 100+100+300+1088+300+100+100 mPylon height: 64.3+144.7+91.4=300.4 mCable length: 153m ~ 577mCurrent stage: deck erection completed (to be built in 2008)


4. Bridging Capacity Challenge on Other Bridges (Cont’d)

SutongSutong CableCable--Stayed Bridge Stayed Bridge (Cont(Cont’’d)d)Single box girder cross sectionSingle box girder cross section

Deck lanes: three traffic lanes + one emergency lane

Deck width: 1.2+2.0+0.5+3.5+3×3.75+3.5+3×3.75+3.5+0.5+2.0+1.2 = 40.4 m

Box depth: 4 m

3.5+3×3.75+0.75 0.75+3×3.75+3.5



Stonecutters CableStonecutters Cable--Stayed BridgeStayed BridgeTwin box girderTwin box girder

Main span: 1018m

Deck width: (3.0+0.6+3.3+11.0+1.6)×2 = 19.5m×2 = 39m

Box depth: 3.93m

Current stage: pylon construction (to be built in 2009)



EdongEdong CableCable--Stayed BridgeStayed BridgeTwin separated box girderTwin separated box girder

Main span: 926m

Deck width: 1.5+1.5+3.5+3×3.75+2.5+3×3.75+3.5+1.5+1.5 = 38.0m

Box depth: 3.5m

Current stage: foundation construction (to be built in 2010) Great Demand and Various Challenges Yao-Jun GE & Hai-Fan XIANG 28


Aerodynamic Flutter of CableAerodynamic Flutter of Cable--Stayed BridgesStayed Bridges

Fundamental frequencies and flutter speedsFundamental frequencies and flutter speeds

92 (59)0.6200.2380.174Single box

81 (59)0.5480.2350.153Twin boxEdong

140(79)0.5050.1840.090Stonecutters Bridge

88 (72)0.5650.1960.104Sutong Bridge

TorsionalVerticalLateral

Flutter Speed(m/s)

Fundamental Frequencies (Hz)BridgeConfiguration

It seems that fundamental frequencies and flutter speeds are not so sensitive to the length of the main span.



Wind and Rain Vibration of Stay CablesWind and Rain Vibration of Stay Cables

Wind tunnel testingWind tunnel testing

Testing results Wind tunnel facility

1 2 3 4 5 6 7 8 9 10

0

5

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15

20

25

30

35

Am

plitu

de(

cm)

Wind speed( m/s)

Rain No rain



Wind and Rain Vibration of Stay Cables Wind and Rain Vibration of Stay Cables (Cont(Cont’’d)d)Vibration control measuresVibration control measures

Spiral wires Surface dimples

4.8 cm4.0 cm31.9 cm3.3 cmΦ158

3.2 cm2.0 cm 32.9 cm2.0 cmΦ139

DimplesSpiral wiresRain-windDry-windCable

Maximum Amplitude



ChaotianmenChaotianmen Arch BridgeArch Bridge

General arrangementGeneral arrangement

Span arrangement: 190+552+190 m (2m longer than Lupu Bridge)Arch truss rise: 142m f/l = 1/3.9Current stage: arch truss erection (to be built in 2008)



ChaotianmenChaotianmen Arch Bridge Arch Bridge (Cont(Cont’’d)d)

Double deck structureDouble deck structure

Upper deck: six-lane highway + two side pedestrian ways

Lower deck: two light-weight railways + two-lane highway


5. Technical Challenge on Twin Spans or Decks

TaizhouTaizhou Suspension Bridge with Twin Main SpansSuspension Bridge with Twin Main SpansTwin main span design schemesTwin main span design schemes

ChaocaoChaocao Bridge in Chile: 1055m + 1100m (in 2002)Bridge in Chile: 1055m + 1100m (in 2002)

QindaoQindao Bay Bridge: 1200m + 1200m (in 2003)Bay Bridge: 1200m + 1200m (in 2003)

MaanshanMaanshan Bridge: 1000m + 1000m (in 2006)Bridge: 1000m + 1000m (in 2006)

TaizhouTaizhou Bridge: 390m +Bridge: 390m + 1080m1080m ++1080m1080m +390m+390m


5. Technical Challenge on Twin Spans or Decks (Cont’d)

TaizhouTaizhou Suspension BridgeSuspension Bridge (Cont(Cont’’d)d)

Design of central pylon (one of the most important concerns)Design of central pylon (one of the most important concerns)

Single main span Single main span Critical turning point Critical turning point Twin main spanTwin main span

Performance of central pylon: longitudinal rigidityPerformance of central pylon: longitudinal rigidity

pp

TTR

δ21 −=

Rp: longitudinal rigidity in MN/m

T1 and T2: horizontal components of cable forces in MN

δp: horizontal displacement in m

δp|T1-T2|



TaizhouTaizhou Suspension BridgeSuspension Bridge (Cont(Cont’’d)d)

Four main factors to longitudinal rigidityFour main factors to longitudinal rigidity

Longitudinal displacement at the top of central pylon:Longitudinal displacement at the top of central pylon:δδpp

Vertical displacement of a deck: Vertical displacement of a deck: δδdd

Max / Min working stress in central pylon: Max / Min working stress in central pylon: δδmaxmax andandδδminmin

Safety factor of sliding resistance between cable and saddle padSafety factor of sliding resistance between cable and saddle pad: K: Kss

) ( 0.2)ln(

2

1codeChinese

TTKs ≥=

μθ

μ= 0.2 based on various experiments

θ: the angle of a saddle arcGreat Demand and Various Challenges

Yao-Jun GE & Hai-Fan XIANG 36


TaizhouTaizhou SuspensionSuspension BridgeBridge (Cont(Cont’’d)d)QualitativeQualitative contrastcontrast ofof centralcentral pylonpylon typestypes

smallestsmallestδδpp andandδδddAA shapedshaped LargestLargest RRpp KK == 2.02.0

largestlargestδδmaxmax andandδδminmin

smallestsmallestδδmaxmax andandδδminminSingleSingle columncolumn SmallestSmallest RRpp KK == 2.02.0

largestlargestδδpp andandδδdd

mediummediumδδpp andandδδddInversedInversed YY MediumMedium RRpp KK == 2.02.0

mediummediumδδmaxmax andandδδminmin



TaizhouTaizhou Suspension BridgeSuspension Bridge (Cont(Cont’’d)d)Quantitative comparison of central pylon typesQuantitative comparison of central pylon types

Inversed Y-shaped steel pylon has been chosen as the final scheme

K sμ=0.2 δd (m) δd /L * δp (m) δp /h σmax σmin1.97 4.513 1/239 1.809 1/101 296 −2002.19 4.863 1/222 2.082 1/88 336 −2161.9 4.321 1/249 1.625 1/112 28.9 −14.22 4.512 1/239 1.768 1/103 28.6 −13.5

1.97 4.416 1/245 1.672 1/109 237 −1312.02 4.505 1/240 1.74 1/105 245 −134

Deck displacement

Column(concrete)

Inversed Y(steel)

Pylon displacement Stress (MPa)Type ofPylon

A-shaped(steel)



NingboNingbo CableCable--Stayed Bridge with Twin Parallel DecksStayed Bridge with Twin Parallel DecksTwin parallel deck cableTwin parallel deck cable--stayed bridgesstayed bridges

Bridge Name Country Pylon Type Foundation Main Span Deck Width Net Interval Interval/Width Onomichi Japan A-shaped Separate 215 m 10.4 m 37.3 m 3.6

Fred Hartman USA Diamond Jointed 381 m 23.8 m 4.7 m 0.2Meikou Nishi Japan A-shaped Separate 405 m 14.5 m 35.5 m 7.9

Diamond 4.9 m 0.2H-shaped 6.9 m 0.3

23.2 mJointed 468 mNingbo China



NingboNingbo CableCable--Stayed BridgeStayed Bridge (Cont(Cont’’d)d)General arrangementGeneral arrangement

Span arrangement: 63 + 132 + Span arrangement: 63 + 132 + 468468 + 132+ 63m+ 132+ 63m

Overall deck design: 8 traffic lanes and 2 emergency lanesOverall deck design: 8 traffic lanes and 2 emergency lanes

Twin parallel deck configuration due to wide deck requirementTwin parallel deck configuration due to wide deck requirement

Structural materials: Structural materials: RC pylon and PC deckRC pylon and PC deck

Economy and structural dampingEconomy and structural damping

Technical comparisons: Technical comparisons: Pylon shape: Pylon shape: 2 types 2 types Deck cross section: 3 typesDeck cross section: 3 types



NingboNingbo CableCable--Stayed BridgeStayed Bridge (Cont(Cont’’d)d)Alternatives of pylon types and sectionsAlternatives of pylon types and sections

35.1

117.

5

21.2 9.09.0

25.5

23.6

6.0

89.0

22.5 5.0 22.558.0

30.3

113.

714

6.6

(a) Twin diamond shape (b) Twin H shape

7 7

1.7 2.

8

9.123.1

2.8

0.9

1.8

5.8 3.0 5.83.06.724.3

1.8 1.820.023.6

2.4

(a) Closed box

(b) Twin separated boxes

(c) Twin side ribs

Alternative Pylon TypesAlternative Cross Sections



NingboNingbo CableCable--Stayed BridgeStayed Bridge (Cont(Cont’’d)d)Comparison of structural dynamic performanceComparison of structural dynamic performance

Bridge DeckCross-Section Diamond H-shaped Diamond H-shaped Diamond H-shaped

Closed box 0.248 0.279 0.31 0.302 0.937 0.896Twin separated box 0.272 0.308 0.308 0.301 0.81 0.794

Twin side rib 0.306 0.345 0.31 0.299 0.599 0.555

Lateral frequencies (Hz ) Vertical frequencies (Hz ) Torsional frequencies (Hz )

Twin diamond shape: higher torsional rigidity and simpler force resistance in pylons

Twin side rib: the most economic scheme but flutter confirmation required

Flutter speed of twin side rib: Ucr= 95m/s > [Ucr] = 66m/s

Vortex-induced vibration: under investigation with high Reynold’s number


6. Conclusions

Great DemandGreat DemandThe rapid economic development and great social The rapid economic development and great social transformation have exerted strong impact on transportation transformation have exerted strong impact on transportation demand in China for the past three decades.demand in China for the past three decades.

The National Trunk Highway System plan with 35,000 km has The National Trunk Highway System plan with 35,000 km has basically met with the great demand since 1988.basically met with the great demand since 1988.

The realization of the National Expressway Network plan with The realization of the National Expressway Network plan with 85,000 km will greatly ease the strong impact and improve 85,000 km will greatly ease the strong impact and improve highway infrastructure in the near future.highway infrastructure in the near future.


6. Conclusions (Cont’d)

Various ChallengesVarious ChallengesThe intrinsic limit of span length due to aerodynamic stability The intrinsic limit of span length due to aerodynamic stability is about is about 1,500m for a traditional suspension bridge. But either an enough1,500m for a traditional suspension bridge. But either an enough--widely widely slotted deck or a narrowly slotted deck with stabilizers could pslotted deck or a narrowly slotted deck with stabilizers could provide a rovide a 5,000m suspension bridge with high enough critical flutter speed5,000m suspension bridge with high enough critical flutter speed..

The main windThe main wind--induced problem in longinduced problem in long--span cablespan cable--stayed bridges is stayed bridges is rainrain--wind induced vibration of stay cables. There is still a room to wind induced vibration of stay cables. There is still a room to enlarge enlarge span length with the consideration of bridge wind resistance.span length with the consideration of bridge wind resistance.

One of the most important concerns in the design of double main One of the most important concerns in the design of double main span span suspension bridge is the selection of longitude rigidity of censuspension bridge is the selection of longitude rigidity of central pylon.tral pylon.

It is necessary to make more comparison of pylon shapes and deckIt is necessary to make more comparison of pylon shapes and decksections in twin parallel deck cablesections in twin parallel deck cable--stayed bridges.stayed bridges.

YaoYao--Jun GE & Jun GE & HaiHai--Fan XIANGFan XIANG

Tongji UniversityTongji University

Shanghai ChinaShanghai China


Keynote Lecture - IABSE Conference - Weimar 2007

Great Demand and Various ChallengesChinese Major Bridges for Improving Traffic

Infrastructure NationwideProf. Dr. Prof. Dr. YaoYao--Jun GE & Prof. Dr. Jun GE & Prof. Dr. HaiHai--Fan XIANGFan XIANG

Documents

1. Traffic Infrastructure Developmentthost-iabse-elearning.org/l8/data/downloads/handouts 4 per page.pdf · Suspension bridge: 1490m (Runyang Bridge, 3rdrd longest in the world)longest