Ramp左转车辆先驶过正线跨线构造物.pptVIP

2.Ramp1）定向式/直接式/左出左进:左转车辆直接从左侧驶出，左转弯，到相交道路的左侧驶入。2.Ramp2）半直接式:又称半定向式匝道（1）左出右进式:左转车辆从左侧直接驶出后左转弯，到相交道路时由右侧驶入。（2）右出左进式:左转车辆从右侧右转驶出，在匝道上左转，到相交道路后直接由左侧驶入。（3）右出右进式:左转车辆都是右转弯驶出和驶入，在匝道上左转改变方向2.Ramp左转车辆先驶过正线跨线构造物,然后向右回转约270°达到左转的目的。2.RampCross-section立交匝道横断面主要由车行道、路缘带、停车带和防撞护栏或路肩组成。匝道横断面形式单向交通应采用单幅式断面,双向交通应采用双向分离式断面。在匝道范围内,路、桥同宽,中央分车带困难路段可采用分隔物(钢护栏和混凝土护栏)。2.Ramp车行道宽应根据车道数、车型及设计速度确定,机动车车道宽度应符合表5.3.1-2所列数值。单车道匝道必须设停车带,停车带含一侧路缘带宽度应为2.75m；当为小型汽车专用匝道时可为2.0m。其他设施最小宽度应符合规程要求。2.RampHorizontalalignment2.RampHorizontalalignment匝道平面线形中,直线与圆曲线或大半径圆曲线与小半径圆曲线之间应设缓和曲线。缓和曲线应采用回旋曲线形式。反向曲线间的两个回旋线,其参数宜相等,不相等时其比值应小于1.5。匝道平曲线可由一条圆曲线及两条缓和曲线组成,也可由两条缓和曲线直接衔接。2.Ramp2.RampProfile/Verticalalignment立交匝道最大纵坡不应大于表规定。2.Ramp各种设计速度的匝道所对应的最小竖曲线半径及竖曲线长度应符合表5.3.3-2的规定***SchoolofCivilEngineering孙仁娟2012.4.24URBANROADDESIGNLecture10-DesignofGradeSeparation-Ⅱ

TheHighFiveinDallas,Texas,USA:anextremeexampleofinterchangedesign.Thisisacomplicatedfive-levelstackinterchangeduetothecloseproximityoffrontageroads.Whyshoulddesigninterchange?ObjectivesLearnsomegrade-separatedintersectiondesignstandards,specification,guidelines;Identifyandcomparegrade-separatedintersection/interchangetypes,advantages/disadvantages;Identifyanddescribegrade-separatedintersection/interchangedesignproceduresandprinciples.TermsGradeseparation/Gradeseparatedintersectionistheprocessofaligningajunctionoftwoormoretransportaxesatdifferentheights(grades)sothattheywillnotdisruptthetrafficflowonothertransitrouteswhentheyacrosseachother.Interchange:isaroadjunctionthattypicallyusesgradeseparation,andoneormoreramps,topermittrafficonatleastonehighwaytopassthroughthejunctionwithoutdirectlycrossinganyothertrafficstream.StackinterchangeCloverleafinterchangeCloverstackinterchangeTurbineinterchangeRoundaboutinterchangeDiamond