ANALYSIS OF REINFORCED CONCRETE PILE CAP STRUCTURAL
BEHAVIOR AS ONSHORE WIND TURBINE FOUNDATION
Pile Cap; Wind Turbine Foundation; Structural Analysis; Finite Element Method.
The growth of the wind energy industry in Brazil has demanded projects of big
size foundations, which in most cases are pile caps. These structural elements
spend close to 300 cubic meters of concrete and 20 tons of steel in its
construction. In this context, a deepest structural analysis about this kind of
wind turbine foundations should contribute to improvement of projects in this
sector, that are of great relevance for the development of the Brazilian energy
matrix. In that way, this work proposes to analyze the structural behavior of
reinforced concrete pile caps, as onshore wind turbine foundations, using
numerical models. In order to do, eight finite elements models were
constructed, with the aid of the ANSYS V17 and SAP2000 V17 softwares. It
was adopted as variables: the finite element type used for modeling the pile cap
and piles (solid or shell); the soil representation (spring or semi-infinite space);
and, the consideration or not of the soil under the pile cap base. All the
materials constitutive models were considered as with linear elastic behavior.
The interest results were: pile´s reaction; division of loading between soil and
piles; pile cap´s deformation; radial normal stress and bending moments in the
pile cap; and, the increase of vertical stresses in the soil. The models designed
in solid elements and plate elements demonstrated good compatibility between
the found values. In some models, the numerical analysis showed results
against the structural safety of the foundation when the soil under the pile cap is
not considered. In addition, an equivalence was found between the soil elastic
properties, such as Young´s modulus (Esoil) and modulus of subgrade reaction
(k s ), in the numerical models analyzed.