18. Vertical Alignment - 2
The chapter discusses the importance of valley curves in transportation engineering, specifically focusing on their design considerations, length, and geometric adjustments needed for safety and comfort. It explains how valley curves are formed by different gradient combinations and how factors like sight distance and headlight operation play crucial roles in their design, especially at night. Proper design of these curves is essential to reduce vehicle discomfort and enhance visibility to prevent accidents.
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Sections
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18.4Problems
This section provides sample problems related to valley curves and their design.
What we have learnt
- Valley curves are vertical curves with convexity downwards formed by gradients meeting.
- Designing valley curves requires ensuring enough headlight sight distance.
- The length of the valley curve is determined based on comfort and safety criteria.
Key Concepts
- -- Valley Curve
- A vertical curve with convexity downwards formed by the meeting of two gradients.
- -- Headlight Sight Distance
- The distance over which a vehicle's headlights can illuminate the roadway, critical for safety during night driving.
- -- Cubic Parabola
- A mathematical shape used in designing valley curves to ensure comfort and safety when transitioning between gradients.
- -- Transition Curve
- A curve that gradually transitions from one alignment to another, often used for adjusting centrifugal force in valley curves.
Additional Learning Materials
Supplementary resources to enhance your learning experience.