Ordinarycranes,usedintheconstructionindustryorforloadingships,canliftweightsofupto200t.Butconsiderthefollowingproblems:aprefabricated1,500tsectionofaship(suchasthewholesuperstructureorthefrontpartofthebow)hastobeplacedinitsfinalposition;a6,000trockethasto...[繼續(xù)閱讀]

    Shelterfromthenaturalelementsisabasicneed.Earlypeoplemetthisneedbydwellingincavesandthentheirdescendantsbegantoconstructbuildings.Keyfactorsinthedesignofthesesheltersweretheclimateandthematerialsavailable.Forexample,inhot,drycountrieshouseswithtinywindows...[繼續(xù)閱讀]

    Thehighestbuildingconstructedby1975wasSearsRoebuckTowerinChicago.Itis443mtallwith110floors.Ithouses16,500peopleandhas103elevatorsand18escalators.Structuralengineershavecalculatedthatbuildingsupto3kmtallaretechnicallyfeasible.WhyhaveLargeBuildings?Thechief...[繼續(xù)閱讀]

    Thefirstroadsusedbypeoplewereprobablybeatenoutbythehoofsofanimalsastheymadetheirwaybetweenfeedingandwateringplaces.Routesthatbeganasmerecattletracksorhuntingandsupplytrailsdevelopedaftertheinventionofthewheelintoharder-wearingroadscrisscrossingtheancientw...[繼續(xù)閱讀]

    Modernroadsystemsevolvedovermanyhundredsofyearsoutofthenetworkofroutesthatlinkedvillagesandtownshipsacrossthelengthandbreadthofeverycountry.Inearlytimes,thefarmerscartthreadeditswaybetweenfields,skirtingwoods,avoidingwater,andseekingthemostconvenientroute...[繼續(xù)閱讀]

    Tunnelingwasprobablyoneofmansearliestexercisesinthefieldofcivilengineering.TheancientEgyptiansareknowntohavebuilttunnelsfortransportingwaterandforuseastombs.TheEgyptiansalsoundertookminingoperations,cuttingdeeptunnelstoexcavatecopperores.Todaytunnelsareus...[繼續(xù)閱讀]

    TheearliestbridgeswereprobablylogsthrownacrossstreamsorthestoneslabclapperbridgessuchasthosestillsurvivinginDevon,England.Anothertypeofwatercrossingwasprovidedbybridgesformedbyboatsfixedtogether.TheGreekhistorianHerodotus(485—425BC)providedtheearliestdocu...[繼續(xù)閱讀]

    Twonineteenth-centuryinventionsledtoarevolutioninbridgebuilding.ThesewerePartlandcementandmass-producedsteel.Cementisthevitalingredientofconcrete,andmassconcretecanbeusedtobuildpiers,abutments(banksupports),andarchesof“artificial”stonetoanyrequiredshape.W...[繼續(xù)閱讀]

    WhenOrvillewright(1871—1948)andhisbrotherWilbur(1867—1912)mademansfirstpoweredflightonDecember17,1903,atkittyHawk,NorthCarolina,theyrevolutionizedtransportation.Intheorythenewaircraftmadepossiblethemovementofmenandgoodsfromanypointonearthtoanyotherwithout...[繼續(xù)閱讀]

    Manbuiltrailroadslongbeforehebuiltsteamenginesandbeforehehadevenmasteredthebasictechnologyofengineeringwithironandothermetals.Theearliesttrainswereconstructedoftimberandwereinoperationnotlaterthanthefourteenthcentury.Theywerebuilttoovercometheseverelimita...[繼續(xù)閱讀]