THERMALLY INDUCED BASE CRACKING IN A PRECAST CONCRETE WIND TURBINE TOWER: FIELD DIAGNOSIS, THERMO-MECHANICAL FINITE-ELEMENT ANALYSIS AND IMPLICATIONS FOR DURABILITY AND SUSTAINABLE LIFETIME EXTENSION

Precast concrete wind turbine towers are subjected to coupled mechanical and thermal actions that are only partially covered by conventional design checks. When such actions are misdiagnosed, sound structures may be repaired repeatedly, downgraded or decommissioned before the end of their technical life, which wastes the embodied carbon already invested in the support structure and shortens the period over which the turbine displaces fossil electricity. This paper presents a thermo-mechanical finite-element diagnostic framework for a hybrid concrete-steel tower affected by diffuse cracking at the base, developed without using the observed crack pattern as a calibration target. The case study combines laser-scanner crack mapping, geoelectrical tomography, destructive and non-destructive concrete testing, in-situ temperature measurements and three-dimensional solid finite-element analysis in linear thermo-elasticity. Field data constrain geometry, material parameters and thermal boundary conditions, while the numerical phase post-processes radial and circumferential stresses in a cylindrical basis. Material non-conformity, foundation-layout defects and global dynamic anomalies are ruled out, and restrained thermal deformation is identified as the governing mechanism. A closed-form benchmark and a regression surrogate calibrated on the numerical results show that the outer-face hoop stress at the restrained base is governed by the external surface temperature rather than by the through-wall gradient alone, and yield an explicit cracking domain. The resulting workflow is transferable, inexpensive and directly usable to support durability-driven lifetime-extension decisions.