Terminology of curve setting – name for a chord shorter than the peg interval In laying out a curve with standard peg (stake) spacing, the chord that is smaller than the peg interval is referred to as:

Introduction / Context:
During field curve setting, stakes are usually placed at equal chainages (peg interval), creating equal standard chords. However, near the beginning or end of a curve—or where the geometry demands—one or more chords may be smaller than the regular interval. The correct term for such a chord is part of standard curve-setting vocabulary.

Given Data / Assumptions:

• There exists a standard peg (stake) spacing along the curve.
• One chord is shorter than this standard spacing.
• Nomenclature follows conventional highway/surveying practice.

Concept / Approach:

The chord equal to the peg interval is termed the normal or standard chord. Any chord less than this standard length is called a sub-chord. Sub-chords commonly occur at the start (first chord) and end (last chord) of a curve to make the layout exactly fit the required tangent points.

Step-by-Step Solution:

Verification / Alternative check:

Most curve-setting tables and deflection angle worksheets include a column for sub-chords with corresponding scaled deflections, confirming standard usage.

Why Other Options Are Wrong:

Small chord/short chord: informal phrases, not standard technical terms.

Normal chord: equals peg interval, the opposite of what is described.

Common Pitfalls:

Forgetting to scale deflection for sub-chords; mixing up sub-chord with sub-tense or sub-tangent; using full deflection for a reduced chord leading to setting errors.

Final Answer:

Sub-chord