When a tornado passed through this wind project at a speed of 166 miles per hour, it caused extensive damage to several wind turbine generators. The client turned to Barr to evaluate wind turbine foundations at the site. We began with a preliminary visual inspection. In one instance, the tower and turbine components for one foundation had not yet been fully assembled, and a crane next to the foundation had collided with the assembled parts. At another foundation site where the tower and turbine components were fully assembled, we observed cracks in the grout below the tower’s bottom flange.
Based on these preliminary findings, Barr completed an additional inspection and oversaw nondestructive testing (NDT) to evaluate a group of additional foundations located in the tornado’s path. This work included NDT examination of one foundation, dynamic-response-analysis testing of 12 more foundations, and a review of anchor-bolt tension checks completed after the tornado struck.
The data obtained from the dynamic response analysis justified a level of confidence that the foundations supporting turbines with damaged blades or other components were not significantly damaged and were behaving similarly to the foundations with no observable damage.