Finite element simulation and sensitivity analysis of concrete wind turbine tower with horizontal joint defects and production defects

The structural safety of prestressed concrete wind turbine towers strongly depends on the grout layer of horizontal joints between precast sections. However, due to influence of construction and environment, grout layer defects and production defects cannot be completely avoided in practical engineering. In this study, the influence of grout-missing defects and production defects on the mechanical performance of concrete tower sections was investigated through numerical simulation. A local four-section tower finite element model was established, and the effects of grout-missing angle, grout-missing width, concrete grade, longitudinal rebar spacing, and concrete cover thickness were systematically analyzed under four load cases. The four load cases are prestressing case, operating case, ultimate load case, and ultimate load case with safety factor. The results show that grout-missing defects increase concrete stress, concrete damage, contact stress, and rebar stress, while reducing the rotational stiffness of tower sections. Generally, when the grout-missing angle exceeds 24 ° and the grout-missing width exceeds 200 mm, the increase in structural response is more significant. External grout-missing defects are more unfavorable than middle grout-missing defects. In contrast, production defects have relatively limited influence on the structural response within the investigated range. Based on the simulation results, a normalized severity index was proposed to distinguish high- and low-severity defect conditions. The results of this paper can provide reference for defect assessment, construction quality control, and future standard revisions of prestressed concrete wind turbine towers.