Monopile type foundations have been mainly applied for offshore wind turbines in Europe, but jacket type foundations may be applied when installation of monopile is difficult due to rock conditions in japan. However, the undersea grouted connection of jacket type foundation possibly increases the nominal contact stress of grout and probably have unreasonable connection shape. Static loading test and FEA for both jacket type foundation with grouted connection and new sleeve pipe footing type foundation with grouted connection have been conducted. As a result, it is clarified the maximum load capacity was lower in the former connection due to the influence of the peeling between steel pipe and concrete, and higher in the latter due to the behavior of steel pipe and concrete as a composite structure.
