Horizontal and Vertical Curves Flashcards
7 cards from real FUNDAMENTAL SURVEYING practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Horizontal and Vertical Curves flashcards as text
Using the chord definition, the degree of curve (Dc) is the central angle subtended by a chord of:
Answer: 100 feet
Both the arc and chord definitions use a 100-foot standard length; the chord definition uses a 100-foot chord rather than a 100-foot arc.
A reverse curve is characterized by:
Answer: Two simple curves joined at a point where they turn in opposite directions
A reverse curve consists of two simple circular curves that curve in opposite directions, joined at the Point of Reverse Curvature (PRC), forming an S-shape.
The long chord (C) of a simple horizontal curve connecting PC to PT is given by:
Answer: C = 2R × sin(Δ/2)
The long chord C = 2R × sin(Δ/2), derived from the isosceles triangle formed by the two radii drawn to PC and PT and the chord itself.
A spiral (transition) curve inserted between a straight tangent and a circular curve primarily serves to:
Answer: Provide a gradual change in centrifugal force and allow smooth superelevation runoff
Spiral curves allow the centrifugal force and superelevation to increase gradually from zero on the tangent to their full values on the circular curve, improving driver comfort and safety.
Using the arc definition, what is the radius of a 2-degree curve?
Answer: 2,864.8 feet
R = 5729.58 / Da = 5729.58 / 2 = 2864.79 ≈ 2,864.8 feet, using the standard arc-definition relationship.
Superelevation on a horizontal curve is designed primarily to:
Answer: Counteract the centrifugal force acting on vehicles navigating the curve
Superelevation tilts the roadway inward on a curve so that the component of gravity helps counteract centrifugal force, improving vehicle stability and safety.
When staking a horizontal curve using the deflection angle method, the deflection angle from the PC to any point on the curve equals:
Answer: Half the central angle subtended by the arc from PC to that point
By the inscribed angle theorem, the deflection angle from the PC equals half the central angle subtended by the arc from the PC to that point.