Calculateur de la longueur des courbes verticales sur les routes
Cette calculatrice est un outil utilisé dans la conception des autoroutes et permet de déterminer la longueur de la courbe verticale des collines sur une route.
This calculator is a tool used in highway design to determine the appropriate vertical curve length at crests (hills) on a road. In roadway design, it is crucial that crests have a sufficient vertical curve length to ensure the safety and comfort of drivers. This Calculateur de la longueur des courbes verticales sur les routes helps engineers and designers meet these requirements.
Lors de l'utilisation en ligne Calculateur de la longueur des courbes verticales sur les routes, you can calculate by entering: Sight Distance, Initial Roadway Grade, Final Roadway Grade, Height of driver’s eye above Roadway surface, and Height of object above Roadway surface information.
Table des matières :
- Understanding How Crest Vertical Curve Length on Roadways is Calculated
- Quelle est la longueur de la courbe verticale de crête sur les routes ?
- Detailed Explanation of the Crest Vertical Curve Length on Roadways Calculation Formula
- Key Considerations in Crest Vertical Curve Length on Roadways Calculation
- Importance of Accurate Crest Vertical Curve Length Calculation in Roadway Design
Understanding How Crest Vertical Curve Length on Roadways is Calculated
Le Calculateur de la longueur des courbes verticales sur les routes determines the necessary length of a vertical curve at a crest to provide adequate sight distance. Here’s a breakdown of the calculation process:
- Gathering Input Parameters: The calculator requires several inputs, including:
- Sight Distance (S): The minimum distance a driver needs to see ahead.
- Initial Roadway Grade (g1): The slope of the road approaching the crest.
- Final Roadway Grade (g2): The slope of the road descending from the crest.
- Height of driver’s eye above Roadway surface (h1): The typical height of a driver’s eye.
- Height of object above Roadway surface (h2): The height of an object on the road that a driver needs to see (e.g., a car).
- Calculating the Algebraic Difference in Grades (A): The absolute difference between the initial and final grades is calculated: A = |g2 – g1|.
- Applying the Appropriate Formula: Le Calculateur de la longueur des courbes verticales sur les routes uses different formulas depending on whether the sight distance is less than or greater than the curve length. These formulas, derived from principles of stopping sight distance, ensure drivers have enough visibility to react to hazards.
- Determining the Minimum Curve Length (Lm): The calculator outputs the minimum required length of the vertical curve to meet the sight distance requirements.
This calculation ensures that the vertical curve is long enough to provide safe stopping sight distance, which is critical for preventing accidents. For more related calculator Cliquez ici.
Quelle est la longueur de la courbe verticale de crête sur les routes ?
Crest vertical curve length on roadways refers to the distance along the curve that connects two intersecting grades (slopes) at the top of a hill or crest. This length is a critical design parameter in highway engineering, as it directly affects driver safety and comfort. A properly designed crest vertical curve ensures that drivers have sufficient sight distance to see objects or hazards ahead, allowing them to react and stop safely.
Le Calculateur de la longueur des courbes verticales sur les routes helps determine this optimal length.
Detailed Explanation of the Crest Vertical Curve Length on Roadways Calculation Formula
Le Calculateur de la longueur des courbes verticales sur les routes uses the following formulas, derived from AASHTO (American Association of State Highway and Transportation Officials) guidelines:
L_m = \frac{{A \times S^2}}{{200 \times (\sqrt{h_1} + \sqrt{h_2})^2}} \quad \forall \, S < L_m L_m = 2S - \left( \frac{{200 \times (\sqrt{h_1} + \sqrt{h_2})^2}}{{A}} \right) \quad \forall \, S > L_mOù:
- A – Absolute difference between g2 and g1 (the algebraic difference in grades)
- S – Sight Distance (usually the stopping sight distance)
- Lm – Longueur minimale de la courbe
- h1 – Height of driver’s eye above roadway surface (typically 3.5 feet or 1.07 meters)
- h2 – Height of object above roadway surface (typically 2.0 feet or 0.61 meters for a tail light)
These formulas account for the geometry of the curve and the required sight distance to ensure driver safety. The Calculateur de la longueur des courbes verticales sur les routes applies the correct formula based on the relationship between sight distance and curve length.
Key Considerations in Crest Vertical Curve Length on Roadways Calculation
Several factors must be considered when calculating the crest vertical curve length on roadways. The Calculateur de la longueur des courbes verticales sur les routes incorporates many of these, but engineers must also exercise judgment:
- Vitesse de conception : Higher design speeds require longer vertical curves to provide adequate stopping sight distance.
- Stopping Sight Distance (SSD): The primary factor in determining curve length. SSD is the distance a driver needs to see ahead to stop safely.
- Driver Eye Height: The assumed height of the driver’s eye above the road surface.
- Object Height: The assumed height of an object on the road that drivers need to see (e.g., a vehicle, a pedestrian).
- Grades: The initial and final grades of the roadway significantly influence the shape and length of the vertical curve.
- AASHTO Standards: Calculations and designs must adhere to guidelines and standards set by organizations like AASHTO.
- Comfort Criteria: While safety is paramount, vertical curves should also be designed to minimize discomfort caused by abrupt changes in vertical acceleration.
- Drainage: The vertical curve design should facilitate proper drainage of water from the roadway.
Le Calculateur de la longueur des courbes verticales sur les routes helps engineers balance these factors to create safe and efficient roadway designs.
Importance of Accurate Crest Vertical Curve Length Calculation in Roadway Design
Accurate calculation of crest vertical curve length is essential for several reasons:
- Sécurité: Ensures drivers have enough time and distance to react to hazards, reducing the risk of accidents.
- Driver Comfort: Provides a smooth transition between grades, minimizing vertical acceleration and improving ride quality.
- Design Efficiency: Optimizes the use of space and materials in roadway construction.
- Conformité: Meets regulatory requirements and design standards.
Le Calculateur de la longueur des courbes verticales sur les routes is a valuable tool for achieving these goals.
For complete vertical alignment, use the Calculateur de la longueur des courbes verticales des routes SAG to analyze both crest and sag vertical curves.