《桥梁工程》课程教学课件（专题讲稿）Principles for Concept Design of Conrete Girder Bridges

PRINCIPLESFORCONCEPTDESIGNOFCONCRETEGIRDERBRIDGES---Basedon Situation inChinaDe-Can YangThe Universityof TennesseeWuhanUniversityof TechnologyNov.21,2008Knoxville

De-Can Yang The University of Tennessee Wuhan University of Technology Nov. 21, 2008 Knoxville PRINCIPLES FOR CONCEPT DESIGN OF CONCRETE GIRDER BRIDGES -Based on Situation in China

ConcreteGirderBridgesConcrete---SteelGirder------Arch; Rigid Frame; Cable-stayed;SuspensionSimple supportedContinuous Systems:Continuous beamContinuousrigid-frameCantileverT-shaped rigid-frameDeck pavement continuous detailsSimple supported changing to continuous systems

Concrete Girder Bridges Concrete-Steel Girder-Arch; Rigid Frame; Cable-stayed; Suspension Simple supported Continuous Systems: Continuous beam Continuous rigid-frame Cantilever T-shaped rigid-frame Deck pavement continuous details Simple supported changing to continuous systems

Outlines1Concept Designvs.Detail Design2Conception of Economical Spans3Simple Supported vs.Continuous System4Continuous Beam vs. Continuous Rigid Frame

Outlines 1 Concept Design vs. Detail Design 2 Conception of Economical Spans 3 Simple Supported vs. Continuous System 4 Continuous Beam vs. Continuous Rigid Frame

Concept Design vs.Detail Design

1 Concept Design vs. Detail Design

lConceptDesignvs.DetailDesignDesign---thePioneerof a ProjectConceptDesign---ThePioneerofPioneersMany Infamous Project----with inborndefectsof conceptdesignFailures in Concept Design----can not be corrected during thedetail design stageand the operation stage5/24DE-CAN YANGPRINCIPLESFORCONCEPTDESIGNOFCONCRETEGIRDERBRIDGES

DE-CAN YANG PRINCIPLES FOR CONCEPT DESIGN OF CONCRETE GIRDER BRIDGES 5/24  Design-the Pioneer of a Project  Concept Design-The Pioneer of Pioneers  Many Infamous Project -with inborn defects of concept design  Failures in Concept Design -can not be corrected during the detail design stage and the operation stage 1 Concept Design vs. Detail Design

ConceptDesignvs.DetailDesignDifferentCriterionsDetailDesign---Codes,Specifications,MechanicsConceptDesign---noobjectiveCriterionConcept Designer's Task·ProposingRecommended Solutionfrom Alternative SolutionsBridge Competition----ThebestwayforConceptDesignAppraisal6/24DE-CAN YANGPRINCIPLESFORCONCEPTDESIGNOFCONCRETEGIRDERBRIDGES

DE-CAN YANG PRINCIPLES FOR CONCEPT DESIGN OF CONCRETE GIRDER BRIDGES 6/24  Different Criterions • Detail Design-Codes, Specifications, Mechanics • Concept Design-no objective Criterion  Concept Designer’s Task • Proposing Recommended Solution from Alternative Solutions  Bridge Competition -The best way for Concept Design Appraisal 1 Concept Design vs. Detail Design

1ConceptDesign vs.Detail DesignThree CommitteesAestheticsCommittee---Architects;ArtistsTechnical Committee---Engineers;ScientistsEstimateCommittee---Auditor,BudgeteerThewinner should bethe highestAesthetics(%)XTechnical(%)/Estimate(inmillion$Formula--suggestedbyanauthorofPCIBridge20087/24DE-CAN YANGPRINCIPLESFORCONCEPTDESIGNOFCONCRETEGIRDERBRIDGES

DE-CAN YANG PRINCIPLES FOR CONCEPT DESIGN OF CONCRETE GIRDER BRIDGES 7/24  Three Committees • Aesthetics Committee-Architects; Artists • Technical Committee-Engineers; Scientists • Estimate Committee-Auditor; Budgeteer  The winner should be the highest Aesthetics (%)×Technical (%)/Estimate (in million $) Formula-suggested by an author of PCI Bridge 2008 1 Concept Design vs. Detail Design

2Conception of Economical Spans

2 Conception of Economical Spans

Conceptionof Economical SpansForMulti-SpanBridgesProject Cost---Each Span LengthDeckSystem:no correlationSuperstructures:negativecorrelation.Substructures:positive correlationBalanced Point·Super Cost =Sub Cost →LowestTotal Project Cost Span Length: Unvaried --- Varied9/24DE-CAN YANGPRINCIPLESFORCONCEPTDESIGNOFCONCRETEGIRDERBRIDGES

DE-CAN YANG PRINCIPLES FOR CONCEPT DESIGN OF CONCRETE GIRDER BRIDGES 9/24  For Multi-Span Bridges  Project Cost-Each Span Length • Deck System: no correlation • Superstructures: negative correlation • Substructures: positive correlation  Balanced Point • Super Cost = Sub Cost  Lowest Total Project Cost  Span Length: Unvaried - Varied 2 Conception of Economical Spans

Conception of Economical SpansMain span length > Need of navigable waterway·Decided byEconomical Span Length Two Branches of Bridge TechnologyExpanding the spanning abilityBuildingthedeep-waterfoundationsHistorical Changeof Economical SpanLength10/24DE-CAN YANGPRINCIPLESFORCONCEPTDESIGNOFCONCRETEGIRDERBRIDGES

DE-CAN YANG PRINCIPLES FOR CONCEPT DESIGN OF CONCRETE GIRDER BRIDGES 10/24  Main span length > Need of navigable waterway • Decided by Economical Span Length  Two Branches of Bridge Technology • Expanding the spanning ability • Building the deep-water foundations  Historical Change of Economical Span Length 2 Conception of Economical Spans