radierna

In Swedish, radierna is the definite plural form of the noun radie, and it refers to two distinct senses that are unrelated: radii in geometry and raft foundations in construction.

Geometrically, a radie (radius) is a line segment from the center of a circle to any point on its boundary. All radii of a given circle have equal length, and the collection of radii helps define the circle’s size and position. The radius r relates to the diameter d by d = 2r, and to area and circumference by A = πr^2 and C = 2πr. Radii underpin the construction of central angles, chords, and arcs, and they radiate from the center to every point on the circle.

In construction, a radier (raft foundation) is a thick concrete slab that distributes the loads from a building over a large area, typically resting on soil. Raft foundations are used to counteract differential settlement and may be reinforced with steel, incorporate edge beams, or be designed as flat, ribbed, or waffle slabs. They are common in areas with weak or expansive soils, in heavy structures, or where shallow bearing capacity or poor soil conditions preclude traditional footings. Design considerations include thickness, reinforcement layout, insulation, and integration with other foundation elements.

See also radii, circle, raft foundation.