Lecture 9 – Route Location and Earthwork (Chap 15, p 652-669) General InfoRoute Location is based on Location AnalysisTopographyOffice StudySelecting horizontal alignmentSelecting vertical alignmentMass diagram pointsLecture 9 – Route Location and Earthwork (Chap 15, p 652-669)General Info Route location is an important step in the design process. It involves many factors related to both physical and political nature. Route Location is based on Location Analysis TopographySoilsEnvironmentEconomicsPoliticalPhases of Route LocationOffice StudyReconnaissancePreliminary LocationFinal LocationTechniques Surveying and mapping Remote sensing-aerial photosComputer graphics-GIS and othersGround survey-transit and level and EDMOnce the general location for the route is known the design process develops in a straight forward manner as follows:Design process (insert sketch of topo)Design Process Draw typical section to define the transverse limits of the roadDefine horizontal alignmentDetermine existing ground profileDetermine plan gradeDraw X-sections at selected stations Determine earthworkRepeatEarthwork is a major component of any road construction project. On most jobs it is desirable to minimize earthwork to lower the cost of the project. To do this consider the following when Selecting horizontal alignmentAvoid major terrain problems and use some of the tipsprovided in the AASHTO Design guide.Selecting vertical alignmentFollow the terrainBalance earthworkMeet existing controlOther considerations such as depressed or elevated roads To calculate earthwork volume use the average end areas technique (example). Then develop a mass diagram to show the accumulation of earthwork in relation to the horizontal location along the job. See Fig 15.15 and Table 15.1 for details. To calculate X-section areas use ACAD Area commandMass diagram pointsBalance point- horizontal line connecting two points on the diagramDirection of earthwork- from the positive slope to the negative slopeFree-haul-a predetermined distance Overhaul distance-(CG to CG) distance minus the free haulOverhaul - overhaul distance times overhaul ordinate.A Calculator for the mass diagram can be obtained by double clicking on the link Calculator for Mass