Comparative analysis of bending moments and rotational stiffness of different wind turbine shallow foundation geometries

Robson Ribeiro¹; José Neres da Silva Filho¹

¹ Universidade Federal do Rio Grande do Norte

doi:10.20906/CPS/CILAMCE2017-1073

Resumo

Wind turbine are structures under high magnitude loads which are result of, mostly, wind action. That being, the foundation of those structures must provide sufficient stiffness, keeping the differential displacements in acceptable ranges, in front of highly eccentric loads providing the required conditions for the wind turbine operation. Wherefore, to compare the efficiency of two different foundation geometries, a comparative analysis of the internal forces developed under ultimate limit state conditions and the rotation stiffness under working loads must be done. The present paper aims to compare three different shallow foundation geometries, those being: circular, square and octagonal footings. This comparative study was parametrized using the maximum soil pressure under the foundation, in way that all of them provided similar values. Such assumption was done to simulate three foundation that could be used in the same soil conditions. The analyses were carried out using the Finite Element Method through the software SAP 2000. The element used were thin plate elements. Four main analyses were carried out: comparison between bending moments; analysis of bending moment variation in front of a change in the subgrade reaction modulus; comparison between rotational stiffness and the variation of rotation stiffness for different subgrade reaction modulus. The study has led to results showing a better performance of the square foundation.

Palavras-chave: Foundation; windturbine; concrete