EGCE 406Bridge Design

Praveen ChompredaMahidol UniversityFirst Semester, 2007

II. Bridge Types

Components of BridgeSubstructure

Foundation (Pile/ Spread Footing)Pier (Column)Abutment

SuperstructureAny structures above bearing which support the roadwayWearing Surface

foundation

deck bearings

abutment

pier

Components of Bridge

Abutment Abutment

Superstructure

Substructure

Roadway Deck

Pier

Abutment

Superstructure

Substructure

Roadway Deck

Components of Bridge

Bearing

Components of Bridge

Bearing

Components of Bridge

Cap Beam

Bearing

Pin Joint

Components of Bridge

Cap Beam

Bearing

Superstructure

Pier

Components of Bridge

Cap Beam

Superstructure

Piers

Span Length

Span > 6 m BridgeSpan < 6 m Culvert

span multi span

span length

single span

Short span: 6-30 mMedium span: 30-100 mLong span: > 100 m

Types of Bridge

Types by Kinds of TrafficTypes by Traffic Position

Types by Material and FabricationTypes by Structural System

Types of Bridge by Traffic

Highway bridge (trucks, cars)Pedestrian bridge (pedestrians, bicycles)Railway bridge (trains)Transit guideway (city trains, monorail)Other types (pipelines, utilities, industrial, aqueduct, airportstructure)

Types: Highway Bridge

Avon Mouth BridgeBristol, UK

Golden Gate BridgeCalifornia, USA

Types: Pedestrian Bridge

El Alamillo BridgeSeville, Spain200m span

Japan Bridge (1994) Paris, France

100m span

Types: Railway Bridge

Stoney Creek Bridge (1894)Canada

325ft span

Mountain Creek Bridge (1880)Canada

Types: Transit Guideway

BTS SystemBangkok, Thailand

Types: Others

Pont du Gard (Roman Aqueduct) (circa 19 BC) Nimes, France

Roman AqueductSpain

Types: Others

Runway at the Los Angeles International Airport (LAX)Los Angeles, USA

Types: Others

Navigational Canal Netherlands

Types of Bridge by Traffic PositionDeck type

Structural components under the deckPreferred by drivers (can clearly see the view)Requires space under the bridge

Through typeStructural components above the deckObstructed view (not a problem for railway bridges)No structure under the bridge

Half-through type

Types: Deck Type

Henry Hudson Bridge (1936)

Rhone BridgeFrance

Types: Through TypeFirth of Forth Bridge (1890)

Scotland521m span

Types: Through Type

Tonegawa River Bridge (1972) Japan

Types: Deck + Through Type Types: Half-Through

Types by Material & FabricationsMaterials

Masonry (brick, rock)TimberReinforced Concrete (RC)Prestressed Concrete (PC)IronSteelAluminumCompositesPlasticsEtc…

FabricationsPrecast (RC/PC)Cast-in-place (RC/PC)Pretensioned (PC)Posttensioned (PC)Prefabricated (steel)Rivet (steel)Bolted (steel/ timber)Welded (steel)Etc…

Types by Material & Fabrications

Timber Bridgeprobably built in place?

Types by Material & Fabrications

Leonardo Da Vinci Bridge (2001)Norway40 m SpanGlue-laminated Timber Bridge

Types by Material & Fabrications

Steel Prefabricated(probably with precast slab)

Types by Material & Fabrications

Prestressed & Precast & Pretensioned(with perhaps precast slab)

Types by Material & FabricationsPrestressed Segmental BridgePrecast & Post-Tensioned

Types of Bridge by Structure

ArchBeamCantileverCable-StayedSuspensionOthers

Types: Arch Bridge

Types: Arch BridgeSemi-circle (has vertical reaction force only)Flat arch (has vertical and horizontal forces at the support)Tied arch (tie resists tension force)

Types: Arch Bridge

keystone

hingless

2 hinged

3 hinged

voussoir

tie

Hinge changes the degree of indeterminatcy in the structure

Types: Arch Bridge

Hinge Detail at the top of an arch bridge

Types: Arch Bridge

The arch construction was invented during the Roman empire

Ponte dei Salti Bridge (circa 1st century AD)

SwitzerlandMasonry Arch

MaterialsMasonryTimberConcrete (Reinforced/ Prestressed)Steel

Types: Masonry Arch BridgePonte Fabricio and Ponte Cestio (65 BC) Tiberina Island, Italy

Types: Masonry Arch Bridge

Ponte Fabricio (65 BC) Tiberina Island, Italy

Ponte Cestio (65 BC) Tiberina Island, Italy

Types: Masonry Arch Bridge Types: Masonry Arch Bridge

Types: Masonry Arch Bridge Types: Concrete Arch Bridge

Bixby Bridge (1932)California, USA

97.5 m spanConcrete arch

Types: Concrete Arch Bridge

Enz Bridge (1961)Mülacker, Germany

46 m spanConcrete arch

Types: Prestressed Concrete Arch

Natchez Trace Parkway Bridge (1994)Tennessee, USA502 m span

Types: Steel Arch Bridge

Sydney Harbor Bridge (1938)Sydney, Australiaparabolic arch 503 m span

Types: Steel Arch Bridge

Construction of Sydney Harbor Bridge

Types: Beam/Girder Bridges

The most basic type of bridgeConsists of a beam simply supported on each side by a pier and can be made continuous laterTypically inexpensive to build

Types: Beam/Girder Bridges

Common MaterialsTimber TrussRC BeamSteel Plate Girder/ Box GirderSteel Truss GirderPrestressed Concrete Precast Girder

I-Beam, U-Beam, T-BeamSegmentally Prestressed Box Beam

Types: Beam/Girder Bridges

simple

cantilever

continuous

Currently, most of the beam bridges are precast (in case of RC and PC) or prefabricatedMost are simply-supportedSome are made continuous on site

Types: Beam/Girder Bridges

Mountain Creek Bridge (1880)CanadaTimber

Types: Beam/Girder Bridges

Steel sections may be hot-rolled shapes (for short-span bridge), Box section (medium span), or Plate Girder (medium span)

hot-rolled box plate girder sections

Types: Beam/Girder BridgesSteel Box Girder Bridge

Types: Beam/Girder Bridges

Upper: Steel Plate Girder BridgeLower: Prestressed Concrete I-Girder Bridge

Types: Beam/Girder Bridges

Steel Plate Girder

Types: Beam/Girder Bridges

Steel Plate Girder(Continuous)

Types: Beam/Girder Bridges

13@2" =26"

6'9"

8"

54"

AASHTO Type IV Girder.

6@2" =12"

28 o 0.5" strands

Typical Cross-Section of Pretensioned AASHTO Type IV girder

Prestressed Concrete Precast (and Pretensioned) sections are usually of I-shape

Types: Beam/Girder BridgesPrecast Pretensioned Prestressed Concrete BridgeSimply-Supported Beam

Types: Beam/Girder BridgesPost-Tensioned Prestressed Concrete are often found in the form of segmentally precast members

Types: Beam/Girder Bridges Types: Beam/Girder BridgesSegmental construction may be constructed in 2 ways

Cantilever Construction –construct from the pier equally on both sidesSpan-by-Span Construction –finish one span at a time

Cantilever

Span-by-Span

Types: Beam/Girder Bridges

Some types of truss bridges can also be considered as a “beam bridge”when looked globally

Types: Beam/Girder Bridges

Types: Beam/Girder Bridges

Steel Truss can be of beam type, arch type, or cantilever typedepending on the primary mechanisms

Types: Beam/Girder Bridges

Components of Truss

Types: Cantilever BridgesBridge roadway is constructed out from the pier in two direction at the same time so that the weight on both side counterbalance each other

Types: Cantilever Bridges

Types: Cantilever Bridges

Steel Truss CantileverPrestressed Concrete Segmental Cantilever Beam

Types: Steel Truss Cantilever Bridge

350'

150'

1700' Firth of Forth Bridge (1890)Scotland

521m span

Types: Steel Truss Cantilever Bridge

Firth of Forth Bridge (1890)Scotland

521m span

Types: Steel Truss Cantilever Bridge

Types: Cantilever BridgesPrestressed Concrete Segmental Cantilever Beam

Columbia River Bridge

USA 1950 ft span

Types: Cable-Stayed Bridge

PIER PIER

ROADWAY DECK

TOWER/ PYLON

Vertical Loads from Traffic

TOWER/ PYLON

Reaction Force Reaction Force

Types: Cable-Stayed Bridge

All the forces are transferred to the pylon

Roadway Materials(Prestressed) Concrete Box RoadwaySteel Box RoadwaySteel Truss Roadway

Types: Cable-Stayed Bridge

Steel Box Beam

I-Shaped Cross Beam

PrecastConcrete Panel

Deck

Types: Cable-Stayed BridgeHarp Type

Fan Type

Types: Cable-Stayed BridgeCable-Stayed Bridge

Rama IX Bridge

Bangkok

450m span

Tatara Bridge

Japan

890m span

Types: Cable-Stayed Bridge Types: Cable-Stayed BridgeConstruction sequence

Types: Cable-Stayed Bridge Types: Cable-Stayed Bridge

Types: Cable-Stayed Bridge Types: Cable-Stayed Bridge

Types: Suspension BridgeSuspension bridge needs to have very strong main cableCables are anchored at the abutment abutment has to be massive

PIER PIER

Vertical Loads from Traffic

ROADWAY DECK

ABUTMENTABUTMENT

TOWER/ PYLONTOWER/ PYLON

Types: Suspension Bridge

Types: Suspension Bridge

London Tower Bridge (1894)London, UK

Types: Suspension Bridge3 Hinges Suspension BridgeTension member is a truss

Types: Suspension Bridge

Tacoma Narrows Bridge (1940)Washington, USA2800 ft span

Types: Suspension BridgeMackinac Bridge (1957)Michigan, USA1158 m span

Types: Suspension Bridge

Akashi Kaikyo Bridge (1998) Japan 1991m central span

Types: Suspension BridgeMillennium Footbridge (2002)London, UK144m span

Types: Suspension Bridge Types: Suspension Bridge

Types: Others

Pontoon (Floating) Bridge

Types: Others

Gateshead Millennium Bridge (2000)Gateshead, UK126m span

The bridge can rotate to allow ships

to go under

Types: Others

Charing Cross Bridge (middle - truss) and Golden Jubilee Bridges (outer – cable-stayed).

Which type should I use?Consider the followings:

Span lengthBridge lengthBeam spacingMaterial availableSite conditions (foundations, height, space constraints)Speed of constructionConstructabilityTechnology/ Equipment availableAestheticsCostAccess for maintenance

Span Length

0 200 400 600 800 1000 1200 1400 1600 1800 2000

slab

concrete girder

steel girder

cable-stayed concrete

cable-stayed steel

steel truss

concrete arch

steel truss arch

steel rib arch

steel suspension

Typ

es

Span Length (m)

Types min maxslab 0 12concrete girder 10 220steel girder 10 270cable-stayed concrete 90 250cable-stayed steel 90 350steel truss 90 550concrete arch 90 300steel truss arch 250 500steel rib arch 120 370steel suspension 300 2000

Span Length

Cost vs. Span Length

The span length may be influenced by the cost of superstructure (cost/meter) and substructure (cost/pier)If the substructure cost is about 25% of total cost shorter span is more cost-effectiveIf the substructure cost is about 50% of total cost longer spans are more economical

Cost vs. Span Length

Substructure here is expensive compared with superstructure

Cost vs. Span Length

If the water is shallow, substructure is inexpensive compared with superstructure

Access for Maintainence

Total Cost = Initial Cost + Maintenance CostBridge should be made easy to inspect and maintainMaintenance cost may govern the selection of bridge

Steel bridge needs a lot of maintenance in coastal regionsConcrete bridge usually require the least maintenance

Beam SpacingBeam spacing determine the number of girdersLarge Spacing

Fewer girder (faster to erect)Deeper and heavier girder (can it be transported?)Reduced redundancyThicker slab

Smaller SpacingMore girderSmaller girderMore redundancy (but more beams to inspect)Thinner slab

Materials

SteelConcrete

Cast-in-placePrecast

Material choice depends on the cost of material at the bridge siteShipping cost from fabricators

Speed of construction

In urban areas, the construction of bridge may disrupt trafficPrefabricated/ Precast member are the only choiceSubstructure construction may disrupt traffic more than the superstructure erection may consider longer spans

Site Requirement

Is the bridge straight or curvedPrecast I-Girder cannot be curvedSegmental prestressed can have slight curveCast-in-place

Is shipping channel required?Shipping of prefabricated pieces to siteIs the temporary falsework required? Can it be done with the site conditions?

Site Requirement

Requirement for shipping channel leads to long span bridge

Site Requirement

Segmental pieces may be easier to ship in narrow urban streets

Site Requirement

In the Millau Aqueduct, the superstructure was completed inland and pushed into the span

Site Requirement

Aesthetics

An ugly bridge, however safe, serviceable, and inexpensive, is not a good bridgeLong span bridge over a river can be a landmark; thus, aesthetics should be an important factorBridge should blend with the environmentSmooth transition between membersAvoid unnecessary decorationsBridge should have an appearance of adequate strength

Aesthetics

Determinant of bridge’s appearance (in order of importance)Vertical and Horizontal geometry relative to surrounding topography and other structuresSuperstructure type: arch, girder, etc…Pier placementAbutment placementSuperstructure shape, parapet and railingPier shapeAbutment shapeColor, surface texture, ornamentationsSigning, Lighting, Lanscaping

Aesthetics Aesthetics

Aesthetics Aesthetics

Aesthetics