DYNAMIC ANALYSIS OF WIND TURBINE PILED RAFT FOUNDATION CONSIDERING SOIL-STRUCTURE INTERACTION AND A NON LINEAR REINFORCED CONCRETE CONSTITUTIVE MODEL.
Wind Turbine Foundation; Soil-structure Interaction; Finite Elements; Dynamic Analysis. Modal Analysis; Cracking; Non-linear.
The present research aims to evaluate foundations stiffness parameters used in
dynamic modal analysis of wind turbine towers, considering a non-linear soil-structure
interaction and taking into account the foundation raft stiffness. Two different analysis
models will be used in this study. Firstly, there will be SAP 2000 models, where the raft
and piles will be modelled, respectively, as shell and frame elements, whilst soil-
structure interaction will accounted using nodal non-linear springs. Additionally,
ABAQUS models with all soil-structure system modelled using 3D solid elements will
be carried on (non-linear elastic constitutive models for soil and non-linear elastic-
plastic constitutive model for reinforced concrete, considering stiffness changes due to
cracking). From model results there will be extracted displacements used to calculate
foundation’s global stiffness, which are input parameters for wind turbine towers modal
analysis models. Parametric analyses will be carried out in order to relate relative soil-
structure stiffness of the pile group and pile cap to their contribution for global dynamic
foundation stiffness. Another import issue that the paper will address is regarding the
effects of concrete cracking on the foundation global rotational stiffness. Is expected
that global stiffness parameter are dependent on service load levels and a relevant effect
of concrete cracking on those stiffness.