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Typical Section - 14070_70
DRAINAGE - 14070_72

Engineering Aid 1 - Advanced Structural engineering guide book
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Figure 3-7.-Curve section. section for a curve, the pavement is a plane surface instead  of  crowned  and  is  usually  superelevated  to account for centrifugal force encountered in curves. The outside  shoulder  slope  is  the  same  as  the  superelevated pavement slope, but the inside shoulder slope is either the same or greater slope. (Inside shoulder refers to the shoulder closest to the center of the arc, or curve.) Most curves are also widened on the inside to allow for  the  “curve  straightening”  effect  of  long  wheelbase vehicles.   The   back   wheels   of   the   trailer   in   a tractor-trailer rig do not follow in the tracks of the tractor wheels. They run closer to the inside edge on the inside lane and closer to the centerline on the outside lane. This presents a safety hazard when two vehicles meet in curves. Curve widening partially eliminates this hazard. Figure 3-7 is a superelevated section showing curve widening.  Specific  guidance  for  curve  widening  is contained  in  NAVFAC  DM-5.5. Preliminary Cross Section Preliminary cross sections  are sectional views of the existing terrain taken at each station point along the center line of the route the road is to take. These sections are usually taken after the roadway has been cleared but may be taken before. If the sections are taken before, the thickness  of  the  sod  to  be  stripped  off  is  normally deducted from the elevations. The preliminary cross section shows the elevations of the natural, or original, ground. These sections, when superimposed on the desired  finished  roadbed  sections,  are  used  for  studying various alignments of the road and for preliminary earthwork   estimating.   Figure   3-8   shows   typical preliminary cross sections. Figure  3-8.—Preliminary  cross  sections. 3-9







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