Successfully reported this slideshow.
Upcoming SlideShare
×

# Topic 4 - Curve

16,907 views

Published on

• Full Name
Comment goes here.

Are you sure you want to Yes No
• Be the first to comment

### Topic 4 - Curve

1. 1. TOPIC 4 CURVES
2. 2. CURVES At the end of the unit you should be able to : Explain the basic concept of curves.  To identify the terminologies of curves.  To differentiate between circular curves, transition curves and vertical curves.  Explain the methods of setting out circular curves.  Calculate setting out of circular curves, transition curves and vertical curves.  Apply the method of setting out of a circular curves and transition curve.
3. 3. ROAD CONSTRUCTION RAILWAY CONSTRUCTION RESERVOIR CONSTRUCTION BUILDING CONSTRUCTION RAILWAY CONSTRUCTION DAM CONSTRUCTION
4. 4. INTRODUCTION is a continuation of the straight lines and curves with a radius of a fixed or variable. PURPOSE to connect a straight line through the point of intersection (θ) which lies between two straight lines to allow the movement to reverse slowly in the horizontal and vertical directions.
5. 5. Reasons for curves construction: Physical state of hilly land, swampy. •Connecting the exit or entrance as the exit roads 'toll‘, •Avoiding the position of the details remain, such as building mosques, cemeteries. •Safety of road users in order to travel more comfortable and secure. •
6. 6. Differentiate Between Circular Curves, Transition Curves and Vertical Curves. Definition Purpose Types Geometry Setting out method
7. 7. CURVES DEFINITON Horizontal curves Curves of constant radius required to connect two straights set out on the ground. Vertical curves The curves are designed and built to connect the straight lines with circular curves Transition curves The curves are designed and made to join two different straight slope.
8. 8. CURVES PURPOSE Horizontal curves Vertical curves Transition curves For the convenience of road users To connect the straight lines with a horizontal curve To avoid the situation where a sudden change in the vehicle entering the curve from a straight round To avoid the situation where a sudden change in the vehicle when it starts down the road after climbing a hill or otherwise.
9. 9. CURVES TYPES Horizontal curves -Circular curves -Transition curves -Compound curves -Reverse curves Vertical curves None Transition curves Crest curves Sag curves
10. 10. CURVES GEOMETRY Horizontal curves δ Vertical curves I θ P T1 T2 R O Transition curves The parabola has the desirable characteristics of (1)a constant rate of change of slope, which contributes to smooth alignment transition, (2)ease of computation of vertical offsets, which permits easily computed curve elevations T1 T1 Crest curves Sag curves T2 T2
11. 11. CURVES – SETTING OUT METHOD Horizontal curves Offset From The Tangent line Offset From The Long chords line Deflection angle method Sub chords line method Vertical curves Wacky turn Setting out the transition curves from T1 to T2 Setting out the transition curves from T4 to T3 Setting out the circular curves from T2 to T3 Transition curves None
12. 12. Circular curves - types R R R2 R1 R1 R2 R2 R1
13. 13. End of sub -topic • Continued….