Horizontal curves
 

 

HOME page for Main Menu

In road and rail construction, horizontal curves are used to smooth the transition when changing direction.

For simple, small radii curves and circular curve is designed.

For larger curves where vehicles and trains are travelling at very high speeds, then compound curves are needed.

A compound curve comprises a start transition, short circular section and finish transition.

A transition curve is used to gradually introduce the centrifugal force experienced when travelling along a circular path at speed.  It begins with an infinite radius which gradually reduces until the radius of the simple circular section is reached.  The following part of the spreadsheet calculates the setting out data for deflection angles of the first transition.  Page 2 and 3 of the spreadsheet completes the circular and final transition sections.

DEFLECTION ANGLE 32 24 0
VELOCITY = 110 kph
RADIUS = 1000 metres
INTERSECTION CHG. 1350.468 metres
MULTIPLES OF THROUGH CHG. 20 metres
RATE OF CHANGE OF RAD. ACC.  q 0.3 m/s3
length of transition 95.093 metres
Shift   S 0.377 metres
Length of main tangent 338.183 metres
distance to first point 7.715 metres
chainage to first point 1020 metres
Chainage at T 1012.285 metres
Chainage at T1 1107.378 metres
               
chainage chord len.   y(m)   def angles  
1012.285 Deg Min Sec
1020.000 7.715 7.715 0.005977 0 0 21
1040.000 20.000 27.715 0.077135 0 4 37
1060.000 20.000 47.715 0.228628 0 13 43
1080.000 20.000 67.715 0.460459 0 27 37
1100.000 20.000 87.715 0.772625 0 46 21
1107.378 7.378 95.093 0.908073 0 54 29

 

Spreadsheets

Home page for Main Menu

horizontal rule

Last Edited :  22 January 2011 14:26:17