Degree of curvature

This article is about the measure of curvature. For other uses, see degree (angle).

Degree of curve or degree of curvature is a measure of curvature of a circular arc used in civil engineering for its easy use in layout surveying.

A n-degree curve turns the forward direction by n degrees over some agreed-upon distance. The usual distance in US road work is 100 ft (30.48 m) of arc.^[1] US railroad work traditionally used 100 ft of chord and this may be used in other places for road work. Other lengths may be used—such as 100 metres where SI is favoured, or a shorter length for sharper curves. Where degree is based on 100 units of length, the conversion between degree and radius is DR = 5729.57795, where D is degree and R is radius.

Since rail routes have very large radii, they are laid out in chords, as the difference to the arc is inconsequential and this made work easier before electronic calculators.

The 100 ft (30.48 m) is called a station, used to define length along a road or other alignment, annotated as stations plus feet 1+00, 2+00 etc. Metric work may use similar notation, such as kilometers plus meters 1+000.

References

↑ Davis, Foote, and Kelly. Surveying Theory and Practice, 1966

External links

Note the variation in usage among these samples.

Railway infrastructure

Permanent way	Permanent way (history) Permanent way (current) Railroad tie/Sleeper Rail fastening system Track ballast Rail profile Fishplate Breather switch Datenail Axe ties Ladder track Baulk road Cant Minimum radius Track transition curve Clip and scotch

Trackwork and track structures	Junction Wye Railroad switch Gauntlet track Railway electrification system Third rail Overhead lines Guide bar Track gauge Track geometry Railway turntable Water crane Track pan Rail track Tramway track Classification yard Rail yard Siding Passing loop Balloon loop Headshunt Refuge siding Dual gauge Roll way

Signalling and safety	Derail Railway signalling Signalling control Wayside horn Railway signal Interlocking Level crossing Buffer stop Catch points Loading gauge Structure gauge Block post Train stop Signal bridge

Buildings	Railway station Station building Railway station layout Station clock Train shed Goods shed Motive power depot Roundhouse Railway platform

Railway track layouts

Running lines	Single track Passing loop Double track Quadruple track Crossover

Rail sidings	Balloon loop Headshunt Refuge siding Rail yard Classification yard

Junctions	Flying junction Level junction Double junction Facing and trailing Grand union Wye Switch / turnout / points Swingnose crossing Level crossing

Stations	Railway platform Side platform Island platform Bay platform Split platform Terminal station Balloon loop Spanish solution Cross-platform interchange Interchange station

Hillclimbing	Horseshoe curve Zig Zag / Switchback Spiral

Track geometry	Track gauge Ruling gradient Minimum curve radius Cant Cant deficiency

Degree of curvature

See also

References

External links