Compound Curve Chainage Calculation Explained

In compound curve construction, we often need to determine the exact location, or chainage, of specific points along the curve. The points of interest usually include the point of curve (PC), the point of compound curvature (PCC), and the point of tangent (PT).

The question provides the following information:

• Length of the first curve (L₁) = 268.3 m
• Chainage at the point of curve (PC) = 623.3 m

We need to find the chainage at the point of compound curvature (PCC).

The point of compound curvature (PCC) is the point where the first curve ends and the second curve begins. To find the chainage at PCC, we add the length of the first curve (L₁) to the chainage at the point of curve (PC).

The formula for chainage at PCC is:

\( \text{Chainage at PCC} = \text{Chainage at PC} + \text{Length of the first curve (L}_1) \)

Let's substitute the given values into the formula:

\( \text{Chainage at PCC} = 623.3 \text{ m} + 268.3 \text{ m} \)

Performing the addition:

\( \text{Chainage at PCC} = 891.6 \text{ m} \)

So, the chainage at the point of compound curvature is 891.6 m.

This calculation shows how the chainage progresses along the first curve from the PC to the PCC.