Offshore structure
As offshore construction fixed to buildings referred to in the open sea off the coast ( english offshore ) were built. They include drilling rigs , production platforms , wind turbines , substations and research platforms, as well as pipelines . In a narrower sense, it is understood to mean structures that are more than twelve nautical miles from the coastline and are therefore outside the national territorial waters .
The pioneering structure of this type was the Roter Sand lighthouse in the German Bight.
As with all major construction projects, it was feared that offshore structures could have an enormous impact on the environment. Among other things, there are concerns that offshore wind farms can have a disruptive effect on resting, foraging and wintering sea birds . Bird strike losses can also occur. In addition, electrical cables between the systems and the land can lead to the formation of artificial magnetic and electrical fields, which can disrupt the orientation of fish. However, recent studies have shown that fish stocks are recovering within the wind farms and that the establishment of facilities is beneficial for the reintroduction of marine animals. Negative effects are limited to the construction phase. Some bird species hunted by sight avoided the wind farm, while other birds did not feel disturbed by the systems.
founding
Special foundation forms are necessary for the safe construction of offshore structures . Truss constructions that are placed on the seabed ( jackets ) have been tried and tested with drilling rigs for a long time . Current developments either rely on constructions that stand on the seabed ( tripods , heavyweight foundations , bucket foundations ) or use the load-bearing capacity of piles that are driven into the seabed ( monopiles , tripile foundations ).
Also being tested are floating offshore foundations (SOF) with large buoyancy bodies that are attached to a heavyweight anchor on the seabed with ropes. The advantage is a further cost saving compared to the systems with solid foundations, since the wind energy systems can be mounted on the SOF in the port and no installation ships are required for the construction. The systems are also easier to dismantle after use.
Web links
- Research in the middle of the sea . BINE information service
Individual evidence
- ↑ Thomas Merck, Henning v. Nordheim: Technical interventions in marine habitats - proceedings. (PDF; 4.3 MB) October 1999, accessed on June 29, 2012 .
- ↑ Peter Kleinort: Offshore passes an impact assessment . In: Daily port report of October 31, 2013, p. 15
- ↑ Mackerel like wind turbines . In: Nordsee-Zeitung , October 31, 2013, accessed on December 28, 2013
- ↑ Rest under rotors . In: Deutschlandradio , October 26, 2011, accessed on October 26, 2011
- ↑ Frank Adam et al .: Development of a foundation for offshore wind turbines from steel-concrete composite components . In: Schiff & Hafen , issue 11/2016, pp. 40–43