Egg cloth

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The egg cloth on the site plan.
Band of curvature of the ovoid

An egg clot (also called an egg line ) is a sequence of design elements used in the alignment of roads and railways . It creates a transition between two circular arcs in the same direction with different radii and occurs when the osculating circles are drawn at two different points on a clothoid . This is only possible if the smaller circle lies in the larger circle and both are not concentric and do not touch each other.

In practice, it often happens that due to local conditions (obstacles, topography) long curves cannot be created with a single circle radius. If, in this case, a radius were simply connected to the following radius without a transition, a cage arch with an unsteady curvature would result. This basket arch carries a higher risk for traffic safety and can be given a steady curve with the help of the egg cloth. When laying out the alignment, make sure that the sequence of the radii is coordinated ( relative alignment ) and that there is at least one change in direction of τ ≥ 3.5 gon.

Individual evidence

  1. ^ Günter Wolf: Street planning . Werner Verlag, Munich 2005, ISBN 3-8041-5003-9 , pp. 125 .