Design of curves
- 1. DESIGN OF CURVES DOLAT RAM (15CRP25) Mehran University of Engineering and Technology, Jamshoro
- 2. CURVES Curves are regular bends provided in the lines of communication like roads, railways etc. They are classified into two main types: 1. Horizontal curve 2. Vertical curve
- 3. HORIZONTAL CURVE A horizontal curve provides a transition between two tangent strips of roadway, allowing a vehicle to negotiate a turn at a gradual rate rather than a sharp cut. The design of the curve is dependent on the intended design speed for the roadway, as well as other factors including drainage and friction.
- 6. Classification of Horizontal Curves Horizontal curves are commonly classified into 4 types: i) Simple Curve ii) Compound Curve iii) Reverse or Serpentine Curve iv) Spiral or Deviation Curve
- 7. Simple, Compound, Reverse and Spiral Simple Curve - Curve with single constant radius. Compound Curve – Two or more curves in succession, turning in the same direction. Reverse Curve – Two simple curves with equal radii turning in opposite directions with a common tangent. Spiral or Deviation Curve – Also called transition curves; placed between tangents and circular curves or between two adjacent circular curves having substantially different radii.
- 10. VERTICAL CURVE A vertical curve provides a transition between two sloped roadways, allowing a vehicle to negotiate the elevation rate change at a gradual rate rather than a sharp cut. The design of the curve is dependent on the intended design speed for the roadway, as well as other factors including drainage, slope, acceptable rate of change, and friction.
- 13. COMPONENTS OF A CURVE R RADIUS PC POINT OF CURVATURE PT POINT OF TANGENCY POC POINT OF CURVE PI POINT OF INTERSECTION L LENGTH OF CURVE T TANGENT DISTANCE LC LONG CHORD E EXTERNAL DISTANCE M MIDDLE ORDINATE D DEGREE OF CURVE I DEFLECTION ANGLE
- 14. FORMULAS FOR SIMPLE CURVE 𝐿 = 𝑅 𝐼 𝜋 180 𝐿𝐶 = 2 𝑅 sin 𝐼 2 𝑇 = 𝑅 tan 𝐼 2 𝐸 = 𝑅 cos 𝐼 2 – 𝑅 𝑀 = 𝑅 − 𝑅 cos 𝐼 2
- 15. STOPPING SIGHT DISTANCE Stopping Sight distance is one of several types of sight distance used in road design. It is a near worst- case distance a vehicle driver needs to be able to see in order have room to stop before colliding with something in the roadway, such as a pedestrian in a crosswalk, a stopped vehicle. Insufficient sight distance can adversely affect the safety or operations of a roadway or intersection.