Fatigue analysis of segmental precast post-tensioned concrete towers under operational wind turbine loads

Recently, segmental precast post-tensioned concrete towers have emerged as a solution for achieving higher hub heights in wind turbines. They are commonly employed as the lower portion of a hybrid tower, with a tubular steel tower situated on top. In this paper, fatigue analyses and evaluations of this tower using a multi-body dynamic model are presented. Initially, the key dimensions of a 160-m hybrid tower were determined based on operational limit state loads. The fatigue life calculations of the segmental precast post-tensioned concrete tower were analysed using this computational model. The influences of the mean stress correction, initial prestress, azimuth angle, and sample size were investigated. The results showed that fatigue accumulation in the horizontal joints of the segmental precast post-tensioned concrete tower was notably influenced by fatigue cycles with larger mean and range values. Furthermore, structural uncertainty analyses revealed that the elastic modulus of the concrete, tower foundation stiffness, and turbine control strategy significantly affected the fatigue damage of the segmental precast post-tensioned concrete tower.