Behaviour and Analysis of Grouted Connections in Offshore Monopile Wind Turbine Structures subject to Bending Moment Loading

In order to assess the structural capacity of grouted connections subject to bending moment loading, a finite element (FE) analysis procedure is adopted for the analysis of a grouted connection in a large diameter monopile support structure used in an offshore wind turbine. The model can accommodate nonlinear material behaviour as well as large displacement behaviour. Three dimensional elements have been used to model the grouted connection and contact elements have been incorporated to represent the interface between the grout and steel. The results obtained from the model have been compared with those obtained from large scale grouted experiments in which the specimens were subjected to flexural loading. A calibrated FE model has been established and used for the analysis of a large diameter monopile support structure used in recent offshore wind energy construction. It has been established that it is essential to incorporate material and geometric nonlinearity, contact behaviour between the steel-grout interface and efficient use of element and mesh configurations in order to correctly simulate the structural behaviour of a grouted connection. The results from the FE analyses show good accordance with the current offshore standard Det Norske Veritas (DNV), 2013. The adopted FE analysis provides sufficient guidance in aid of design of grouted connections in offshore monopile structures resisting bending moment loading.