The hinge point of a slope is a specific location defined by where different graded sections of earth meet, crucial in roadside design for safety.
Based on the provided definition:
- The hinge point is the shoulder point, which is where the paved or unpaved earth shoulder meets the foreslope. This definition applies specifically whenever the foreslope is steeper than a 6:1 ratio.
- Whenever the safety section grading is 6:1 or flatter, the hinge point is defined differently. In this case, the hinge point is where the safety section grading meets the foreslope.
In essence, the location of the hinge point depends on the steepness of the surrounding slopes:
Understanding the Hinge Point
The hinge point is a critical term primarily used in civil engineering and transportation design, particularly concerning the grading of roadsides or embankments. It marks a transition zone between different slope rates.
Locating the Hinge Point
The definition provides two scenarios for identifying the hinge point:
-
Steep Foreslope (Steeper than 6:1):
- In this scenario, the hinge point is where the earth shoulder directly connects with the foreslope. Think of the "shoulder point" as the edge where the shoulder ends and the slope begins.
- Example: If you have a road shoulder and then a steep slope dropping away (e.g., 4:1, 3:1), the hinge point is the line where that shoulder meets the steep slope.
-
Flat Safety Section (6:1 or Flatter):
- When the area adjacent to the shoulder (often called the safety section) is graded with a gentle slope (like 6:1, 8:1, 10:1, etc.), the hinge point is where this safety section grading transitions into the foreslope.
- Example: If the area next to the shoulder is graded at a 6:1 slope for a distance, and then a steeper foreslope begins, the hinge point is the line where the 6:1 safety section meets the beginning of the steeper foreslope.
This distinction is important in design standards to ensure consistency and predictability in how slopes are defined and measured, especially concerning safety features.
