Experimental and numerical investigations of grouted joints in monopiles subjected to early-age cycling

During the hardening process of the grout, grouted joints that are assembled offshore are typically subjected to mainly wave-induced relative movements between grouted steel members of monopile structures for offshore wind turbines. In order to determine the dimensions of the relative movements, numerical simulations of mechanisms causing relative movement between the ungrouted steel members are carried out for different sea states that are to be expected during the grouting and hardening process. The effects of early-age movement on the material properties of grout material are evaluated on the basis of experimental simulations. It is shown that the effects on the properties of hardened grout are complex.