Road curve

Last updated

Road curves are irregular bends in roads to bring a graduation change of direction. Similar curves are on railways and canals.

Contents

Curves provided in the horizontal plane are known as horizontal curves and are generally circular or parabolic. Curves provided in the vertical plane are known as vertical curve.

Five types of horizontal curves on roads and railways:

Two types of vertical curves on roads:

Horizontal Curve

Simple curve

Diagram of simple curve Curve 2014-08-18 12-57.jpg
Diagram of simple curve

A simple curve has the same radius throughout and is a single arc of a circle, with two tangents meeting at the intersection (B in this diagram).

Compound curve

Diagram of compound curve Road curve 2014-08-18 12-16.jpg
Diagram of compound curve

A compound curve has two or more simple curves with different radii that bend the same way and are on the same side of a common tangent. In this diagram, MN is the common tangent.

Reverse curve

Diagram of reverse curve Curve 2014-08-18 12-52.jpg
Diagram of reverse curve

Also called a serpentine curve, it is the reverse of a compound curve, and two simple curves bent in opposite directions are on opposite sides of the common tangent.

Deviation curve

Diagram of deviation curve Curve 2014-08-18 12-19.jpg
Diagram of deviation curve

A deviation curve is simply a combination of two reverse curves. It is used when it is necessary to deviate from a given straight path to avoid intervening obstructions such as a building, a body of water, or other significant site.

Transition curve

Is a curve with a gradual change in elevation on the outside of the curve to help drivers comfortably take turns at faster speeds

Vertical road

Valley curve

Also called a sag curve, this curve dips down and then rises back up. These are placed in the base of hills. The opposite of summit curve.

Summit curve

Also called the crest curve, this curve rises and then dips down. At the peak of hills. The opposite of valley curve.

See also

Related Research Articles

Angle Figure formed by two rays meeting at a common point

In Euclidean geometry, an angle is the figure formed by two rays, called the sides of the angle, sharing a common endpoint, called the vertex of the angle. Angles formed by two rays lie in the plane that contains the rays. Angles are also formed by the intersection of two planes. These are called dihedral angles. Two intersecting curves may also define an angle, which is the angle of the rays lying tangent to the respective curves at their point of intersection.

Analytic geometry Study of geometry using a coordinate system

In classical mathematics, analytic geometry, also known as coordinate geometry or Cartesian geometry, is the study of geometry using a coordinate system. This contrasts with synthetic geometry.

Parabola Plane curve: conic section

In mathematics, a parabola is a plane curve which is mirror-symmetrical and is approximately U-shaped. It fits several superficially different mathematical descriptions, which can all be proved to define exactly the same curves.

Slope Mathematical term

In mathematics, the slope or gradient of a line is a number that describes both the direction and the steepness of the line. Slope is often denoted by the letter m; there is no clear answer to the question why the letter m is used for slope, but its earliest use in English appears in O'Brien (1844) who wrote the equation of a straight line as "y = mx + b" and it can also be found in Todhunter (1888) who wrote it as "y = mx + c".

Inclined plane Tilted flat supporting surface

An inclined plane, also known as a ramp, is a flat supporting surface tilted at an angle, with one end higher than the other, used as an aid for raising or lowering a load. The inclined plane is one of the six classical simple machines defined by Renaissance scientists. Inclined planes are used to move heavy loads over vertical obstacles. Examples vary from a ramp used to load goods into a truck, to a person walking up a pedestrian ramp, to an automobile or railroad train climbing a grade.

Horizon Apparent line that separates earth from sky

The horizon is the apparent line that separates the surface of a celestial body from its sky when viewed from the perspective of an observer on or near the surface of the relevant body. This line divides all viewing directions based on whether it intersects the relevant body's surface or not.

Phase diagram Chart used to show conditions at which physical phases of a substance occur

A phase diagram in physical chemistry, engineering, mineralogy, and materials science is a type of chart used to show conditions at which thermodynamically distinct phases occur and coexist at equilibrium.

Azeotrope

An azeotrope or a constant boiling point mixture is a mixture of two or more liquids whose proportions cannot be altered or changed by simple distillation. This happens when an azeotrope is boiled, the vapour has the same proportions of constituents as the unboiled mixture. Because their composition is unchanged by distillation, azeotropes are also called constant boiling point mixtures.

Perpendicular Relationship between two lines that meet at a right angle (90 degrees)

In elementary geometry, two geometric objects are perpendicular if they intersect at a right angle.

Fault (geology) Fracture or discontinuity in rock across which there has been displacement

In geology, a fault is a planar fracture or discontinuity in a volume of rock across which there has been significant displacement as a result of rock-mass movements. Large faults within Earth's crust result from the action of plate tectonic forces, with the largest forming the boundaries between the plates, such as subduction zones or transform faults. Energy release associated with rapid movement on active faults is the cause of most earthquakes. Faults may also displace slowly, by aseismic creep.

Grade (slope) Angle to the horizontal plane

The grade of a physical feature, landform or constructed line refers to the tangent of the angle of that surface to the horizontal. It is a special case of the slope, where zero indicates horizontality. A larger number indicates higher or steeper degree of "tilt". Often slope is calculated as a ratio of "rise" to "run", or as a fraction in which run is the horizontal distance and rise is the vertical distance.

Horopter

The horopter was originally defined in geometric terms as the locus of points in space that make the same angle at each eye with the fixation point, although more recently in studies of binocular vision it is taken to be the locus of points in space that have the same disparity as fixation. This can be defined theoretically as the points in space that project on corresponding points in the two retinas, that is, on anatomically identical points. The horopter can be measured empirically in which it is defined using some criterion.

Track transition curve Mathematically-calculated curve in which a straight section changes into a curve

A track transition curve, or spiral easement, is a mathematically-calculated curve on a section of highway, or railroad track, in which a straight section changes into a curve. It is designed to prevent sudden changes in lateral acceleration. In plane, the start of the transition of the horizontal curve is at infinite radius, and at the end of the transition, it has the same radius as the curve itself and so forms a very broad spiral. At the same time, in the vertical plane, the outside of the curve is gradually raised until the correct degree of bank is reached.

Cue sports techniques

Cue sports techniques are a vital important aspect of game play in the various cue sports such as carom billiards, pool, snooker and other games. Such techniques are used on each shot in an attempt to achieve an immediate aim such as scoring or playing a safety, while at the same time exercising control over the positioning of the cue ball and often the object balls for the next shot or inning.

Field hockey stick Means by which field hockey is played

In field hockey, each player carries a stick and cannot take part in the game without it. The stick for an adult is usually in the range 89–95 cm (35–38 in) long. A maximum length of 105 cm (41.3") was stipulated from 2015. The maximum permitted weight is 737 grams. The majority of players use a stick in the range 19 oz to 22 oz. Traditionally hockey sticks were made of hickory, ash or mulberry wood with the head of the sticks being hand carved and therefore required skilled craftsmen to produce. Sticks made of wood continue to be made but the higher grade sticks are now manufactured from composite materials which were first permitted after 1992. These sticks usually contain a combination of fibreglass, aramid fiber and carbon fibre in varying proportions according to the characteristics required.

Architectural drawing Technical drawing of a building (or building project)

An architectural drawing or architect's drawing is a technical drawing of a building that falls within the definition of architecture. Architectural drawings are used by architects and others for a number of purposes: to develop a design idea into a coherent proposal, to communicate ideas and concepts, to convince clients of the merits of a design, to assist a building contractor to construct it based on design intent, as a record of the design and planned development, or to make a record of a building that already exists.

Geometric design of roads Geometry of road design

The geometric design of roads is the branch of highway engineering concerned with the positioning of the physical elements of the roadway according to standards and constraints. The basic objectives in geometric design are to optimize efficiency and safety while minimizing cost and environmental damage. Geometric design also affects an emerging fifth objective called "livability," which is defined as designing roads to foster broader community goals, including providing access to employment, schools, businesses and residences, accommodate a range of travel modes such as walking, bicycling, transit, and automobiles, and minimizing fuel use, emissions and environmental damage.

Track geometry Three-dimensional geometry of track layouts and associated measurements

Track geometry is concerned with the properties and relations of points, lines, curves, and surfaces in the three-dimensional positioning of railroad track. The term is also applied to measurements used in design, construction and maintenance of track. Track geometry involves standards, speed limits and other regulations in the areas of track gauge, alignment, elevation, curvature and track surface. Standards are usually separately expressed for horizontal and vertical layouts although track geometry is three-dimensional.

In astronomy, geography, and related sciences and contexts, a direction or plane passing by a given point is said to be vertical if it contains the local gravity direction at that point. Conversely, a direction or plane is said to be horizontal if it is perpendicular to the vertical direction. In general, something that is vertical can be drawn from up to down, such as the y-axis in the Cartesian coordinate system.

The moment-area theorem is an engineering tool to derive the slope, rotation and deflection of beams and frames. This theorem was developed by Mohr and later stated namely by Charles Ezra Greene in 1873. This method is advantageous when we solve problems involving beams, especially for those subjected to a series of concentrated loadings or having segments with different moments of inertia.

References