Curves are regular bend which are provided in transportation lines like roads, railways etc. and also in canals to avoid obstructions. Curves also provided in vertical direction like flyovers etc.
The curves provided in horizontal direction is know as Vertical Curves and which are provided in horizontal are Horizontal Curves. Horizontal Curves are constructed by taking a centre on earth.
Compound Curve
The curve consists of two or more simple curves. All curves have different radius bends in same direction. The centre of all curves lie in same side of curve.
Reverse Curve (Sepentine Curve)
The curve made up of two arcs having same or different radius. Both curves bends in opposite sides with a common tangent at their junction. Their centre also lie in opposite side.
It is used when straight or tangent of both curves are parallel or meet at very small angles. These type of curve should be avoided where speed of vehicles require necessarily high.
Deviation Curve
It is simply combination of two reverse curves. It is used where there is need of deviation from straight path to avoid obstructions like trees, buildings etc.
Simple Curve.
The curves provided in horizontal direction is know as Vertical Curves and which are provided in horizontal are Horizontal Curves. Horizontal Curves are constructed by taking a centre on earth.
Name of Components of Simple Curve
- AB and BC are tangents to curve. AB and BC are also known as First Tangent and Second Tangent respectively.
- The point where curves touch tangents are known as tangent points. T1and T2 are tangent points.
- The angles made by intersection of two tangent is called angle of intersection. It is denoted as I.
- The angle at which first tangent deflect from second tangent is called deflection angle of curve (Ф).
- The line drawn between two tangent points T1 and T2 is known as long chord passing through point E.
- The arc T1FT2is length of curve.
- The midpoint of curve (F) is know as apex or summit of curve.
- The distance between apex of curve and intersection point is known as apex distance.
- The distance between apex point and midpoint of curve is called as versed sine of curve.
- The angle subtended by curve T1FT2 at centre is equal to deflection angle of curve and knowns as central angle.
Classification of Curves
Simple Curve
A simple curve is made up of a single arc of a circle having raidus r. The radius remains same throughout all point of curve.
A simple curve is made up of a single arc of a circle having raidus r. The radius remains same throughout all point of curve.
Compound Curve
The curve consists of two or more simple curves. All curves have different radius bends in same direction. The centre of all curves lie in same side of curve.
Reverse Curve (Sepentine Curve)
The curve made up of two arcs having same or different radius. Both curves bends in opposite sides with a common tangent at their junction. Their centre also lie in opposite side.
It is used when straight or tangent of both curves are parallel or meet at very small angles. These type of curve should be avoided where speed of vehicles require necessarily high.
Deviation Curve
It is simply combination of two reverse curves. It is used where there is need of deviation from straight path to avoid obstructions like trees, buildings etc.
Simple Curve.
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