This document discusses different types of curves used on highways and railways to change the direction of motion. A simple curve consists of a single arc of a circle that is tangential to both the straight lines it connects. It is defined by its radius or degree of curvature. The elements of a simple curve include the angle of deflection and mid ordinate offsets that define its shape and position relative to the tangent lines.

1. SIMPLE CIRCULAR CURVE

2. INTRODUCTON
• CURVES ARE GENERALLY USED ON HIGHWAY
AND RAILWAYS WHERE IT IS NECESSARY TO
CHANGE THE DIRECTION OF MOTION
• A CURVE MAY BE DIVIDED INTO 3 TYPES:
1. SIMPLE
2. COMPOUND
3. REVERSE
4. DEVIATION CURVE

4. 1) SIMPLE CURVE
• A SIMPLE CURVE IS THE ONE WHICH CONSIST
OF A SINGLE ARC OF A CIRCLE.
• IT IS TANGENTIAL TO BOTH THE STRAIGHT
LINE

5. 2) COMPOUND CURVE
• A Compound curve consists of two or more
simple arcs of different radius that turn in the
same direction and join at common tangent
point
• There centre lies on the same side of curve

6. 3) REVERSE CURVE
• It is a curve made up of two arcs of equal or different
radii bending in opposite side of a common tangent
at their junction.
• Centre of curve lies on the opposite side of a
common tangent.
• They are also called as ‘S’ curves
Common tangent

7. 4) DEVIATION CURVE
• It is a combination of two reverse curves.
• It consists of three arcs or curves of different or equal radii.
• It is provide when it become essential to deviate from a given
straight path to avoid obstacles.

8. Angle of Intersection
Various parts of curve

13. Designation of Curve
• Degree of curve :
or
(30 m)

14. Relationship between degree and radian of curve
(Chord length=30m)

15. Elements of simple curve
1) Angle of deflection ( )

19. Mid Ordinate

22. 1) Perpendicular offset from tangent

24. 2) Radial offset from tangent
O1
O2