Unit Test ReviewUnit Test Review

Updated 4/24/2012.

FAMOUS BRIDGESFAMOUS BRIDGESFAMOUS BRIDGESFAMOUS BRIDGESBridge Name Location Importance

Brooklyn BridgeBrooklyn BridgeBrooklyn – Manhattan, NYCBrooklyn – Manhattan, NYC

crosses East Rivercrosses East River

Designer: John Roebling; completed in 1883Designer: John Roebling; completed in 1883

Used caissons to build piers (caisson disease)Used caissons to build piers (caisson disease)

Uses cable-stayed AND main cable designsUses cable-stayed AND main cable designs

George WashingtonGeorge Washington Manhattan, NYC – Fort Lee, NJ Manhattan, NYC – Fort Lee, NJ crosses Hudson Rivercrosses Hudson River

First modern suspension bridge built after collapse of Quebec First modern suspension bridge built after collapse of Quebec Bridge during construction, proved strength and safety of Bridge during construction, proved strength and safety of suspension bridges for very long crossingssuspension bridges for very long crossings

Golden Gate BridgeGolden Gate Bridge San Francisco – Marin County, San Francisco – Marin County, CA; crosses Golden GateCA; crosses Golden Gate

National iconNational icon

Oakland BayOakland BayOakland – San FranciscoOakland – San Francisco

crosses Oakland Baycrosses Oakland Bay

Collapsed in earthquake in 1989Collapsed in earthquake in 1989

Two bridges combined: suspension & beamTwo bridges combined: suspension & beam

On-ramp section melted in truck fire in 2007On-ramp section melted in truck fire in 2007

Sunshine SkywaySunshine SkywayBradenton – St. Petersburg, FLBradenton – St. Petersburg, FL

crosses Tampa Baycrosses Tampa Bay

Freighter hit it in 1980Freighter hit it in 1980

Rebuilt with cable-stayed designRebuilt with cable-stayed design

Uses damage-sensing monitors (smart bridge), dolphinsUses damage-sensing monitors (smart bridge), dolphins

Tacoma NarrowsTacoma Narrows

(“Galloping Gertie”)(“Galloping Gertie”)

Tacoma – Gig Harbor, WA Tacoma – Gig Harbor, WA

crosses Tacoma Narrowscrosses Tacoma Narrows

Collapsed in 1940, ignored effect of constant 40 mph windCollapsed in 1940, ignored effect of constant 40 mph wind

Rebuilt in 1950 using flexible, open designRebuilt in 1950 using flexible, open design

Parallel bridge completed in 2007Parallel bridge completed in 2007

Verrazano NarrowsVerrazano NarrowsBrooklyn – Staten Island, NYCBrooklyn – Staten Island, NYC

crosses Verrazano Narrowscrosses Verrazano NarrowsLongest suspension span in the United StatesLongest suspension span in the United States

Akashi KaikyoAkashi KaikyoKobe – Awaji Island, JapanKobe – Awaji Island, Japan

crosses Akashi Straightcrosses Akashi StraightLongest suspension span in the world, built across a fault lineLongest suspension span in the world, built across a fault line

PURPOSE of BRIDGESPURPOSE of BRIDGESPURPOSE of BRIDGESPURPOSE of BRIDGES

Bridges cross barriers (water, chasms, low areas, Bridges cross barriers (water, chasms, low areas, roads, other bridges)roads, other bridges)

Primary purpose: get people and their goods to the Primary purpose: get people and their goods to the other side of barriersother side of barriers

Roman bridgesRoman bridges1.1. Move armies/troops to conquer landMove armies/troops to conquer land

2.2. Move goods (trade) throughout empireMove goods (trade) throughout empire Form & functionForm & function: balance the beauty (shape) of a : balance the beauty (shape) of a

bridge with its purpose (usefulness, strength)bridge with its purpose (usefulness, strength) CommerceCommerce: carry trade and services between cities: carry trade and services between cities

Main typeMain type Roadbed supportRoadbed support Sub-typeSub-type ExampleExample

Beam straight pieces

triangles

Truss Usher Park bridge

Trestle

Girder RR bridge over Spring Brook

Draw Chicago River draw bridges

King Post Morton Arboretum ped bridges

Arch curves

Roman curved deck Irving Park ped. bridge

Through

Half-through

Deck

Suspension suspended from cables

Main (anchored) cable

Golden Gate

Akashi Kaikyo

Verrazano Narrows

Cable-stayedSunshine Skyway

Brooklyn Bridge

TYPES of BRIDGESTYPES of BRIDGESTYPES of BRIDGESTYPES of BRIDGES

Beam Bridge TypesBeam Bridge TypesBeam Bridge TypesBeam Bridge Types

Triangle

Truss

Trestle

Draw Bridge

King Post

King Post

Beam BridgesBeam BridgesBeam BridgesBeam Bridges

Firth of Forth Rail Bridge

New Zealand trestle bridge

box beam

Chicago draw bridges

girder bridge, Itasca

Arch Bridge TypesArch Bridge TypesArch Bridge TypesArch Bridge Types

THROUGH ARCHHALF-THROUGH ARCHDECK ARCHROADBEDROMAN ARCH

Arch BridgesArch BridgesArch BridgesArch Bridges

on the California Hwy.

aqueduct, Segovia, Spain

Rialto Bridge, Venice

Eads Bridge, St. Louis

Suspension Bridge TypesSuspension Bridge TypesSuspension Bridge TypesSuspension Bridge Types

ROADBEDMAIN (ANCHORED) CABLE

PIERS (TOWERS)CABLE-STAYED

Suspension BridgesSuspension BridgesSuspension BridgesSuspension Bridges

Millau Viaduct, France

Mackinac Bridge,

Michigan

Zakim Bridge, Boston

Clifton Bridge, Bristol, England

Capilano Bridge, Vancouver

OTHER BRIDGESOTHER BRIDGESOTHER BRIDGESOTHER BRIDGES

aqueductaqueduct: bridge that carries water: bridge that carries water cantilevercantilever: bridge with middle section supported by : bridge with middle section supported by

counterweightscounterweights pontoonpontoon: bridge that floats: bridge that floats

PARTS of a BRIDGEPARTS of a BRIDGEPARTS of a BRIDGEPARTS of a BRIDGE

LengthSpan

RoadbedRoadbed: carries the traffic: carries the traffic SuperstructureSuperstructure: part of bridge above the roadbed: part of bridge above the roadbed SubstructureSubstructure: part of bridge below the roadbed: part of bridge below the roadbed PierPier: primary vertical support: primary vertical support LengthLength: distance from one end of bridge to the other, : distance from one end of bridge to the other,

including access roadwaysincluding access roadways SpanSpan

Arch/beam: distance from edge to edge of area crossedArch/beam: distance from edge to edge of area crossed Suspension: distance from one pier/tower to the otherSuspension: distance from one pier/tower to the other

PARTS of a BRIDGEPARTS of a BRIDGEPARTS of a BRIDGEPARTS of a BRIDGE

CaissonCaisson: pier construction method where sections : pier construction method where sections are sunk as the river bottom is dug out insideare sunk as the river bottom is dug out inside

DolphinDolphin: “bumper” that protects bridge piers from : “bumper” that protects bridge piers from boat trafficboat traffic

JOINTSJOINTSJOINTSJOINTS ButtButt: end of one piece attached : end of one piece attached

to side of another at right anglesto side of another at right angles MiterMiter: end of one piece attached : end of one piece attached

to side at an angle, often 45 to side at an angle, often 45 degreesdegrees

NotchNotch: both pieces cut halfway : both pieces cut halfway through and joined, like Lincoln through and joined, like Lincoln logslogs

LapLap: end of one piece is “hung” : end of one piece is “hung” over the side of anotherover the side of another

LaminationLamination: full length of two : full length of two sides are attached to each othersides are attached to each other

NATURAL MATERIALSNATURAL MATERIALSNATURAL MATERIALSNATURAL MATERIALS

No tools yetNo tools yet hanging vineshanging vines piles of stones, rocks moved by waterpiles of stones, rocks moved by water fallen treesfallen trees

FIRST BRIDGESFIRST BRIDGESFIRST BRIDGESFIRST BRIDGES Tools were neededTools were needed

woven vines, ropeswoven vines, ropes stepping stones placed stepping stones placed

by humansby humans woodwood

MODERN MATERIALSMODERN MATERIALSMODERN MATERIALSMODERN MATERIALS Modern (since Roman times)Modern (since Roman times)

stone (Roman arch)stone (Roman arch) wood (covered bridges)wood (covered bridges) iron (early railroad, cracked easily)iron (early railroad, cracked easily) steel (requires painting to prevent rust)steel (requires painting to prevent rust) steel-reinforced concretesteel-reinforced concrete

STRESSES and FORCESSTRESSES and FORCESSTRESSES and FORCESSTRESSES and FORCES compressioncompression: squeezing or pressing together: squeezing or pressing together tensiontension: stretching or pulling apart: stretching or pulling apart neutral axisneutral axis: point in a beam where compression and tension : point in a beam where compression and tension

are equalare equal torsiontorsion: torque or twisting motion: torque or twisting motion oscillationoscillation: bending or swinging back and forth in an even : bending or swinging back and forth in an even

rhythmrhythm shearshear: two parallel and opposing compression forces (think : two parallel and opposing compression forces (think

scissors)scissors)

Compression

Tension

APPLYING STRESSAPPLYING STRESSAPPLYING STRESSAPPLYING STRESS shapesshapes

triangletriangle: strongest shape for resisting bridge forces: strongest shape for resisting bridge forces rackingracking: collapse of a rectangle to a parallelogram; : collapse of a rectangle to a parallelogram;

corrected by bracingcorrected by bracing loadsloads

deaddead: the weight of the bridge load itself: the weight of the bridge load itself livelive: the weight of loads that change, e.g., traffic, wind, ice, : the weight of loads that change, e.g., traffic, wind, ice,

snowsnow

BRIDGE SAFETYBRIDGE SAFETYBRIDGE SAFETYBRIDGE SAFETY

civil engineercivil engineer: a design engineer who builds : a design engineer who builds municipal infrastructure, i.e., bridges, roads, power municipal infrastructure, i.e., bridges, roads, power plants, etc.plants, etc.

bridge failuresbridge failures: about 150 to 200 bridges, partially or : about 150 to 200 bridges, partially or totally each year in the U.S.totally each year in the U.S.

inspectionsinspections: U.S. bridges over 20 feet require : U.S. bridges over 20 feet require inspections every 2 yearsinspections every 2 years

““smart” bridgessmart” bridges: use computer sensors to warn of : use computer sensors to warn of damage before it gets seriousdamage before it gets serious