Grade

In civil engineering and surveying, elevation grade, abbreviated as GR, refers to the slope or incline of a surface, typically the slope of the land or the gradient of a road, pathway, or other construction project.  It represents the change in elevation or vertical distance over a specific horizontal distance.

Here are the common ways to express elevation grade

• Ratio  -  The ratio expresses the change in elevation per unit of horizontal distance.  For example, a 1:10 grade means that for every 10 units of horizontal distance, the elevation increases or decreases by 1 unit.  A steeper grade would have a smaller ratio, indicating a larger change in elevation over a shorter horizontal distance.
• Percentage  -  The percentage grade is another way to express elevation grade.  It represents the vertical rise or fall over a horizontal distance as a percentage.  For example, a 10% grade indicates that the elevation changes by 10 units for every 100 units of horizontal distance.
• Degrees  -  Elevation grade can also be expressed in degrees, particularly when working with slope angles.  The slope angle is the angle between the surface and the horizontal plane.  For example, a 45-degree slope indicates a steep incline, while a smaller degree value represents a gentler slope.

Elevation grades are crucial in civil engineering and construction projects.  They determine the feasibility, safety, and design of infrastructure such as roads, railways, drainage systems, and buildings. Properly understanding and calculating elevation grades are essential for ensuring proper drainage, accessibility, and stability of constructed elements.