Monopiles are simple structures commonly used as foundations for offshore wind turbines. They are composed of a large diameter welded steel tubular section that is piled deep in the seabed ensuring load transmission to support the upper structure. There are, however, concerns in terms of their stability due to the variable nature of the seabed, currents, and their resultant effects such as scour, that gain importance with the increase of the size and power of the elements above the water line. The whole structure acts like a lever, with the place of greatest loading typically being the area around the mudline, with the wind and sea working against the structure constantly.
Long term monitoring is therefore a competitive solution for controlling the structure, replacing visual inspections and surveys that can be difficult to implement or may give meaningless data. Fiber Bragg Grating (FBG) based sensing systems are most suited to harsh environments, including submersion in salty water, with long leads between sensors and the acquisition system. They can give valuable insights into the ‘hammering’ process required in the installation of the monopiles offshore. All this with an incredibly fast installation and setup with the possibility to access data remotely or combine it to the windfarm system for generating reports and alarms. What lies beneath the seabed? How will the steel structure react to the piling? Is the pile over or under-designed? How will the structure behave over time? Will the structure bear the wind turbine generator reliably over many years of service at sea? Valuable, reliable data from HBK can help here.
Join this webinar to learn more about using fiber optic sensors for such applications. We will share our experience in designing FBG monitoring systems, their advantages, and best practices.