A berm is a horizontal piece or a ledge in the embankment of a dam , a wall , an excavation or on a slope. It divides the embankment into two or more sections. A berm is supposed to reduce the earth pressure on the foot of the embankment. An embankment with a steep slope and berms is more stable than a continuous embankment without berms. A break in the slope is thus avoided.
Berms can be used as a walkway or driveway on either side of a dam, as a dam can be better maintained from there. Lines and cables can also be laid there.
In the case of sloping construction pits, a bench serves to catch material that slips down. It must be used from a trench depth of around 3.00 m. The execution is regulated in DIN 4124. According to the German accident prevention regulations , berms must be at least 0.60 m wide to be walked on; Berms to catch slipping parts even at least 1.50 m.
The term berm is used in hydraulic engineering , earthworks , dike construction , opencast mining , in archeology and in fortress construction .
In medieval fortress construction, Berme referred to a flat piece of earth between the city wall , castle wall or fortress wall or a parapet and a ditch in front of it. The berm should absorb the pressure of the wall and thus relieve the inner often steep slope or the area of the inner trench lining wall / escarp wall in order to avoid static collapse of the inner trench slope . When parts of the wall fell due to bombardment with blids or later mortars and cannons , the existence of a berm largely prevented the debris from filling the trench.
Forest or forest berms in the Oldenburger Land
A national cultural and historical special feature called forest or forest-berms at the former state highways in the Oldenburg region . These are are longitudinally located roads, an average of 30 meters wide strip of land, often on long distance with forest planted are . Such berms are mainly found on the Geest in the south of Oldenburg. The berms were built between 1820 and 1850/1860 as part of the expansion of the old Oldenburg state roads. These characteristic landscape elements are considered to be of cultural and historical value and therefore worth preserving.
A beautiful berm can also be found in Słubice : the town's dam is also covered with trees ( linden ).
When it became known in 2008 that the Lower Saxony state government under Christian Wulff had transferred the forest berms as "surplus" land to the "Landesliegenschaftsfonds Niedersachsen" special fund and had sold it since 2005, there was strong opposition. By mid-2008, the state property fund had already sold 278,000 square meters of the Bermen for 257,000 euros. The nature and homeland protector Eilert Tantzen then presented to the Minister of Economics and Transport Walter Hirche and managed to stop this action immediately.
Norms and standards
- DIN 4124 - excavation pits and trenches - embankments, shoring, working area widths
- Additional technical contract conditions and guidelines for earthworks in road construction (ZTVE-StB 94)
- ↑ Batran, Bläsi, Eichner: Basic knowledge of construction . 14th edition. Handwerk und Technik Verlag, 2002, ISBN 3-582-03500-X , p. 51
- ^ Eilert Tantzen : The forest / forest berms on the former state highways in the Oldenburger Land . In: Oldenburger Jahrbuch 2009 , Volume 109. Isensee, Oldenburg 2009, pp. 313–329