Detection, Evaluation, and Reinforcement of Anchor Bolt Foundation Damage After Wind Turbine Tower Collapse

Abstract

This paper presents an on-site anchor bolt tension-force versus deformation detection method, which enables the assessment and evaluation of the extent of damage in the anchored zone of anchor bolts buried deep within concrete. In addition, considering different toppling modes and their respective force mechanisms, the paper proposes using the entire cross-sectional plastic bending moment with a 0.4 impact coefficient as the actual effective bending moment for the anchor bolt foundation. This is employed to calculate the tensile forces in the anchor bolts and the local compressive bearing capacity of the concrete above the lower anchor plate. The computational results indicate that the plastic damage in the anchored zone of problematic anchor bolts is primarily caused by the crushing of concrete above the lower anchor plate rather than axial plastic deformation of the anchor bolts. Accordingly, targeted reinforcement schemes for repairing lower anchor plate deformations and replacing locally crushed concrete are proposed and successfully applied, providing practical reference for engineering applications.