Etude du comportement en fatigue d'un coulis (grout) soumis à des efforts de compression et de cisaillement dans le contexte d'une connexion en grout pour les structures d'éoliennes offshores
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Boukerrou_66621500_2018.pdf
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- The demand for electricity continues to increase, and the use of green energy and all the more incentive than ever because of the energy conversion that the world knows. The choice of wind energy production has therefore grown to meet the electricity needs. A need which results in the increase of the geometrical dimensions of the wind turbines and thus of the wind turbines which produce more and which are heavier. Wind turbines are then installed all over the world in the ground, onshore and offshore. One of the most popular off-shore wind turbines is single-base wind turbines, suitable for water depths up to 30 m. In these types of foundations, the pile is bonded coaxially to the upper part of the wind turbine (the mast) via a cement-based connection of high strength cement. Mainly used to transmit vertical forces, which is the case for the offshore structures of oil and gas platforms. In the case of offshore wind structures, the forces transmitted to the foundations are vibrations induced by the winds and the waves, as a result of the bending moments arising at the grout connection causing forces along the three orthogonal directions. However, the norms from which they derive the analytic formulas for sizing connections in grout such as DNV, consider only the vertical forces in the formulas, something which made the analytical calculation relevant because it does not take up the real constraints of problem. And even less interesting when it comes to fatigue design. The grout undergoes during its operation fatigue stresses generating radial and longitudinal cracks due to exceeding the tensile strength of grout. The general objective of this work is to better understand the structural behavior of grout subjected to cyclic compression and shear forces.