道路交通工程专业外文翻译外文文献英文文献Word下载.docx

道路交通工程专业外文翻译外文文献英文文献Word下载.docx

《道路交通工程专业外文翻译外文文献英文文献Word下载.docx》由会员分享，可在线阅读，更多相关《道路交通工程专业外文翻译外文文献英文文献Word下载.docx（9页珍藏版）》请在冰豆网上搜索。

TheBasicsofaGoodRoad

Wehaveknownhowtobuildgoodroadsforalongtime.ArchaeologistshavefoundancientEgyptianroadsthatcarriedblockstothepyramidsin4600BCE.Later,theRomansbuiltanextensiveroadsystem,usingthesameprinciplesweusetoday.Someoftheseroadsare

stillinservice.

Ifyoufollowthebasicconceptsofroadbuilding,youwillcreatearoadthatwilllast.Thetencommandmentsofagoodroadare:

（1）Getwaterawayfromtheroad

（2）Buildonafirmfoundation

（3）Usethebestmaterials

（4）Compactalllayersproperly

（5）Designfortrafficloadsandvolumes

（6）Designformaintenance

（7）Paveonlywhenready

（8）Buildfromthebottomup

（9）Protectyourinvestment

（10）Keepgoodrecords

1．Getwaterawayfromtheroad

Wecan’toveremphasizetheimportanceofgooddrainage.Engineersestimatethatatleast90%ofaroad’sproblemscanberelatedtoexcesswaterortopoorwaterdrainage.Toomuchwaterinanylayerofaroad’sstructurecanweakenthatlayer,leadingtofailure.

Inthesurfacelayer,watercancausecracksandpotholes.Inlowerlayersitunderminessupport,causingcracksandpotholes.Acommonsignofwaterinanasphaltroadsurfaceisalligatorcracking—aninterconnectedpatternofcracksformingsmallirregularshapedpiecesthatlooklikealligatorskin.Edgecracking,frostheaves,andspringbreakupofpavementsalsopointtomoistureproblems.

Topreventtheseproblemsrememberthatwater:

•flowsdownhill

•needstoflowsomeplace

•isaproblemifitisnotflowing

Effectivedrainagesystemsdivert,drainanddisposeofwater.Todothistheyuseinterceptorditchesandslopes,roadcrowns,andditchandculvertsystems.

Divert—Interceptorditches,locatedbetweentheroadandhighergroundalongtheroad,keepthewaterfromreachingtheroadway.Theseditchesmustslopesotheycarrywaterawayfromtheroad.

Drain—Creatingacrownintheroadsoitishigheralongthecenterlinethanattheedgesencourageswatertoflowofftheroad.Typicallyapavedcrownshouldbe1⁄4"

higherthantheshoulderforeachfootofwidthfromthecenterlinetotheedge.Forgravelsurfacesthecrown

shouldbe1⁄2"

higherperfootofwidth.Forthisflowpathtowork,theroadsurfacemustberelativelywatertight.Roadshouldersalsomustbeslopedawayfromtheroadtocontinuecarryingtheflowaway.Superelevations（banking）attheoutsideofcurveswillalsohelpdrain

theroadsurface.

Dispose—Aditchandculvertsystemcarrieswaterawayfromtheroadstructure.Ditchesshouldbeatleastonefootlowerthanthebottomofthegravelroadlayerthatdrainstheroadway.Theymustbekeptcleanandmustbeslopedtomovewaterintonaturaldrainage.Ifwaterstaysintheditchesitcanseepbackintotheroadstructureandundermineitsstrength.Ditchesshouldalsobeprotectedfromerosionbyplantinggrass,orinstallingrockandothererosioncontrolmeasures.Erosioncandamageshouldersandditches,clogculverts,undermineroadbeds,andcontaminatenearbystreamsandlakes.Evaluateyourditchandculvertsystemtwiceayeartoensurethatitworks.Inthefall,cleanoutleavesandbranchesthatcanblockflow.Inspring,checkforandremovesiltsfromplowingandanydeadplantmaterialleftfromthefall.

2．Buildonafirmfoundation

Aroadisonlyasgoodasitsfoundation.Ahighwaywearsoutfromthetopdownbutfallsapartfromthebottom.Theroadbasemustcarrytheentirestructureandthetrafficthatusesit.

Tomakeafirmfoundationyoumayneedtostabilizetheroadbedwithchemicalstabilizers,largestonecalledbreakerrun,orgeotextilefabric.Whenyourunintoconditionswhereyoususpectthatthenativesoilisunstable,workwithanengineertoinvestigatethesituationanddesignanappropriatesolution.

3．Usethebestmaterials

Withallroadmaterialsyou“paynoworpaylater.”Inferiormaterialsmayrequireextensivemaintenancethroughouttheroad’slife.Theymayalsoforceyoutoreplacetheroadprematurely.

Crushedaggregateisthebestmaterialforthebasecourse.Thesharpanglesofthecrushedmaterialinterlockwhentheyarecompacted.Thissupportsthepavementandtrafficbytransmittingtheloadfromparticletoparticle.Bycontrast,roundedparticlesactlikeball

bearings,movingunderloads.

Angularparticlesaremorestablethanroundedparticles.

Asphaltandconcretepavementmaterialsmustbeofthehighestquality,designedfortheconditions,obtainedfromestablishedfirms,andtestedtoensureitmeetsspecifications.

4．Compactalllayers

Ingeneral,themoredenselyamaterialiscompacted,thestrongeritis.Compactionalsoshrinksoreliminatesopenspaces（voids）betweenparticles.Thismeansthatlesswatercanenterthestructure.Waterinsoilcanweakenthestructureorleadtofrostheaves.Thisisespeciallyimportantforunsurfaced（gravel）roads.Usegravelwhichhasamixofsizes（well-gradedaggregate）sosmallerparticlescanfillthevoidsbetweenlargerones.Good

compactionofasphaltpavementlengthensitslife.

5．Designfortrafficloadsandvolumes

Designforthehighestanticipatedloadtheroadwillcarry.Aroadthathasbeendesignedonlyforcarswillnotstanduptotrucks.Onetruckwith9tonsonasinglerearaxledoesasmuchdamagetoaroadasnearly10,000cars.

Ruralroadsmaycarrylogtrucks,milktrucks,firedepartmentpumpertrucks,orconstructionequipment.Ifyoudon’tknowwhatspecificloadstheroadwillcarry,agoodruleofthumbistodesignforthelargestpieceofhighwaymaintenanceequipmentthatwillbeusedontheroad.

Awell-constructedandmaintainedasphaltroadshouldlast20yearswithoutmajorrepairsorreconstruction.Indesigningaroad,usetrafficcountsthatprojectnumbersandsizesofvehicles20yearsintothefuture.Theseareonlyprojections,atbest,buttheywillallowyoutoplanfortrafficloadingsthrougharoad’slife.

6．Designformaintenance

Withoutmaintenancearoadwillrapidlydeteriorateandfail.Designyourroadssotheycanbeeasilymaintained.Thismeans:

•adequateditchesthatcanbecleanedregularly

•culvertsthataremarkedforeasylocatinginthespring

•enoughspaceforsnowafteritisplowedofftheroad

•propercrossslopesforsafety,maintenanceandtoavoidsnowdrifts

•roadsidesthatareplantedortreatedtopreventerosion

•roadsidesthatcanbemowedsafely

Aruleofthumbforadequateroadwidthistomakeitwideenoughforasnowplowtopassanothervehiclewithoutleavingthetravelledway.

Markculvertswithapostsotheycanbelocatedeasily.

7．Paveonlywhenready

Itisnotnecessarytopaveallyourroadsimmediately.Thereisnothingwrongwithawell-builtandwellmaintainedgravelroadiftrafficloadsandvolumedonotrequireapavedsurface.Threehundredvehiclesperdayistherecommendedminimumtojustifypaving.

Don’tassumethatlayingdownasphaltwillfixagravelroadthatisfailing.Beforeyoupave,makesureyouhaveanadequatecrushedstonebasethatdrainswellandisproperlycompacted.Therecommendedminimumdepthofcrushedstonebaseis10"

dependingonsubgradesoils.Aroadpavedonlywhenitisreadywillfaroutperformonethatisconstructedtooquickly.

8．Ê

Buildfromthebottomup

Thiscommandmentmayseemobvious,butitmeansthatyoushouldn’ttopdressorresurfacearoadiftheproblemisinanunderlyinglayer.Beforeyoudoanyroadimprovement,locatethecauseofanysurfaceproblems.Chooseanimprovementtechniquethatwilladdresstheproblem.Thismaymeanrecyclingorremovingallroadmaterialsdowntothenativesoilandrebuildingeverything.Doinganyworkthatdoesn’tsolvetheproblemisawasteofmoneyandeffort.

9．Ê

Protectyourinvestment

Theroadsystemcanbeyourmunicipality’sbiggestinvestment.Justasahomeneedspaintingoranewroof,aroadmustbemaintained.Wisconsin’ssevereclimaterequiresmoreroadmaintenancethaninmilderplaces.Dotheseimportantmaintenanceactivities:

Surface—grade,shape,patch,sealcracks,controldust,removesnowandice

Drainage—cleanandrepairditchesandculverts;

removeallexcessmaterial

Roadside—cutbrush,trimtreesandroadsideplantings,controlerosion

Trafficservice—cleanandrepairorreplacesigns

Designroadswithadequateditchessotheycanbemaintainedwithamotorgrader.Cleanandgradeditchestomaintainproperpitchandpeakefficiency.Aftergrading,removeallexcessmaterialfromtheshoulder.

10．Keepgoodrecords

Yourmaintenancewillbemoreefficientwithgoodrecords.Knowingtheroad’sconstruction,life,andrepairhistorymakesitmucheasiertoplanandbudgetitsfuturerepairs.Recordscanalsohelpyouevaluatetheeffectivenessoftherepairmethodsandmaterialsyouused.

Goodrecordkeepingstartswithaninventoryofthesystem.Itshouldincludethehistoryandsurfaceconditionoftheroadway,identifyandevaluateculvertsandbridges,noteditchconditions,shoulders,signs,andsuchstructuresasretainingwallsandguardrails.

Updateyourinventoryeachyearorwhenyourepairorchangearoadsection.Aformalpavementmanagementsystemcanhelpusetheserecordsandplanandbudgetroadimprovements.

Resources

TheBasicsofaGoodRoad#17649,UW-Madison,15min.videotape.PresentstheTenCommandmentsofaGoodRoad.VideotapesareloanedfreethroughCountyExtensionoffices.

AsphaltPASERManual（39pp）,ConcretePASERManual（48pp）,GravelPASERManual（32pp）.Thesebookletscontainextensivephotosanddescriptionsofroadsurfaces

tohelpyouunderstandtypesofdistressconditionsandtheircauses.Asimpleprocedureforratingthecondition