Light pole
A light mast (LiMa) is the name given to masts with spotlights that are used to illuminate large areas. Permanently installed, they are usually made of cast iron , steel , aluminum or concrete and anchored in the ground by a concrete base . There are also mobile versions.
Light masts are used for street lighting , for illuminating company premises , parking lots or construction sites.
Mobile light masts
Light masts also exist in mobile form at the fire brigade and the THW for technical assistance and other technical support services . Many emergency vehicles, from fire fighting vehicles to rescue vehicles, have extendable light masts. Alternatively, special lighting trailers and equipment trolleys up to and including separate specialist groups (THW: specialist group lighting ) are available.
In the police force , mobile light masts are used, for example, to illuminate a crime scene or incident site (for example, the scene of an accident ). For this purpose, own “ light mast vehicles” (LiMaKW) or trailers are often used. The mast with the light basket is extended.
Stationary light poles
Stationary light masts are relatively long-lived, a service life of several decades is common or is at least aimed at. In the case of steel versions (welded from sheet metal to form a tube, extruded or cast and in some cases mechanically further brought into the final shape), today the surface is typically hot-dip galvanized, whereas in the past mostly anti-rust paint was used. Stainless steel versions are rarer, but are sometimes used in representative areas.
The electrical or other installations are serviced or replaced relatively frequently. For maintenance purposes, special vehicle lifts are used to replace lamps that have aged or failed. With electrical lighting, the ballast coils and starters as well as the connection or distribution point are usually mounted behind a flap in the profile approx. 1 m above the ground, which can be opened with special electric keys.
The usual environmental influences such as sun, rain or wind are rather uncritical for the property because they were taken into account during the construction. On the other hand, major storms, clinging snow or even ice curtains are critical, especially when z. B. due to previous damage (such as a ram impact from a vehicle or other structural weaknesses) the original condition is no longer given. In the event of impacts, such a light mast dents like any other tubular object, which drastically increases the risk of buckling, known from similar structures in statics. Since light masts are often on embankments, their foundations can shift or slip, causing the mast to stand at an angle or even fall over. Trees and other permanent objects in the vicinity pose a certain risk, as they are indirect, e.g. B. by striking in wind or concentrating wind currents that can endanger masts. Particularly exposed locations, such as in port areas, continue to harbor their specific risks.
In the case of the attacks on September 11, 2001 when the Pentagon struck, some of the light masts there were also used to reconstruct the aircraft's approach line. The masts standing in the approach lane had been cut just below their tip according to the picture documents (the typical kink with break was recognizable), so that the upper part fell freely to the ground, while the lower part broke free from its screwed anchorage and onto roadways or . Green spaces tipped over. On the basis of environmental features of the image documents, it was also possible to determine that these rubble were cleared to the side relatively quickly, in order to later serve again in strongly changed positions for press purposes as one image motif of several.
Other possible uses
Similar plants
literature
- Thomas Schindele: Lecture notes for technical mechanics, edition of the 1989/90 winter semester, mechanical engineering department, Kempten / Allgäu University of Applied Sciences