Concepts Topographic Map Contour Lines

1/14 

Concepts

Highway Design Project  WWhoho to stastart?rt?  What are the steps?

Highway Design Principals

Amir Samimi

Civil Engineering Department Sharif University of Technology

2/14  3/14 

Topographic Map Contour Lines

 Contou r lin es ar e lin es th at co nnect po ints t hat a re o f t he sa me elevation.  They show the exact elevation, the shape of the land, and the steepness of the land’s slope.  Contour lines never touch or cross.

 A topographic map, also known as a contour map, is a map that shows the shape of the land using contour line.  It is a map that shows and elevation field, meaning how high and low the ground is in relation to sea level. 4/14  5/14 

What is a benchmark? What is a contour interval?

 A bebenchmarknchmark isis a popointint wwherehere eexactxact eelevationlevation isis knownknown aandnd isis  A cocontourntour inintervalterval isis tthehe ddifferenceifference in eelevationlevation betweebetweenn two marked with a brass or aluminum plate. It is marked BM on contour lines that are side by side. the map with the elevation numbers given in feet.  Remember that a contour interval is not the distance between  Benchmarks are useful to help determine contour lines. the two lines – to get the distance you need to use the map scale.

6/14  7/14 

Close Together? Dark Colored Contour Lines

 If the co ntou r lin es ar e cl ose togeth er, t he n t hat ind icates t hat  The da rk co lo red co ntou r lines rep rese nt eve ry fift h co ntou r area has a steep slope. line to make it easier to read the map.  If the contour lines are far apart, then that indicates the land has a gentle slope (low slope). 8/14  9/14 

How to Use Contour Lines? Vertical Alignment

 VeVeryry ssimple.imple.  ObjectObjective:ive:  You guess!  Determine elevation to ensure  Proper drainage  Acceptable level of safety  Primary challenge  Transition between two grades  VtilVertical curves

Sag Vertical Curve

G1 G2 G1 G2 Crest Vertical Curve

10/14  11/14 

Horizontal Curve Superelevation

Rv ≈  Objective: W p  F f  Fcp  Geometry of directional transition to ensure: Fc  Safety  Comfort

 Primary challenge e  Transition between two directions  W 1 ft  Horizontal curves  Fundamentals   Circular curves α   Superelevation Δ  WV 2  WV 2   W sin  f s W cos  sin   cos   gRv  gRv 12/14  13/14 

Superelevation Parameters Superelevation Transition

 PrPracticalactical limilimitsts oonn supesuperelevationrelevation (e)  Climate  Constructability  Adjacent land use

 Side friction factor (fs) variations  Vehicle speed  Pavement texture  Tire condition

14/14 

Cost Benefit Analysis

 The ma in steps an d objecti ves