2.70 - A parabolic vertical curve is to connect a –2.2% gradient to a +1.9% gradient...
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Interactive Audio Lesson
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Understanding Vertical Curves
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Today we're going to discuss vertical curves and why they're vital in road design. Can anyone tell me what a vertical curve is?
Is it the smooth transition between different gradients on a road?
Exactly! Vertical curves help vehicles change elevation more smoothly. Now, which gradients are we connecting in our example?
We're connecting a -2.2% gradient to a +1.9% gradient.
Calculating Vertical Curve Length
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Now, let's delve into how to calculate the length of a vertical curve. What factors do we need to consider?
We need to consider the design speed and the gradients!
Correct! The design speed here is 85 km/h. For our specific gradients, the required length of the vertical curve is determined by design standards. What was our calculated curve length?
It's 14.282 m.
Great job! That length ensures safe visibility and comfort for drivers.
The Importance of Vertical Curves
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Let's wrap up by discussing the broader implications of using vertical curves. Why do you think they are critical in design?
They help maintain a safe line of sight for drivers.
And they provide a more comfortable driving experience!
Exactly! The role of vertical curves in road safety cannot be overstated. They allow drivers to see ahead and make informed driving choices.
Introduction & Overview
Read summaries of the section's main ideas at different levels of detail.
Quick Overview
Standard
It elaborates on the design standards for vertical curves connecting a –2.2% gradient to a +1.9% gradient on roads, emphasizing key calculations based on a design speed of 85 km/h.
Detailed
In this section, we discuss the design of a parabolic vertical curve connecting a -2.2% gradient to a +1.9% gradient for a road designed for a speed of 85 km/h. Vertical curves are essential in highway design as they influence the driver's line of sight and comfort. The required length of the curve is determined using design standards that consider the gradients involved and the design speed of the road, ultimately allowing for safe and efficient vehicle movement. For this specific case, the calculated minimum length of the curve is 14.282 m.
Key Concepts
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Vertical Curve: A design feature that allows gradual transitions between gradients.
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Gradient: The steeper or gentler incline represented as a percentage.
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Design Speed: Speed for which the roadway is designed to ensure safety.
Examples & Applications
If a road transitions from a -2.2% gradient to a +1.9% gradient, a vertical curve is necessary for smooth elevation change.
Implementing a vertical curve will enable drivers to maintain visibility around bends.
Memory Aids
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Rhymes
Curves go round, make hills less steep, drive with comfort, feel safe and neat.
Stories
Imagine a car approaching a hill. Just before it climbs, the road gently rises, helping the driver see the view ahead, ensuring comfort on the rise.
Memory Tools
GVD - Gradient, Visibility, Design speed - the key aspects of designing vertical curves.
Acronyms
CURVE - Connect Underlying gradients, Reduce vehicle discomfort, Visibility enhancement.
Flash Cards
Glossary
- Vertical Curve
A section of roadway that connects two different gradients, allowing for a smooth transition in elevation.
- Gradient
The slope or steepness of the road, expressed as a percentage.
- Design Speed
The maximum speed at which a road is designed to be safe for the majority of vehicles.
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