A DESERT STORM: SOLAR FACILITY WIND DAMAGE

In 2017 a wind event resulted in the failure of a number of panels of a newly installed solar power generating facility in Arizona. The solar array featured a popular single-axis tracker system designed for wind speeds well above those measured during the failure. Through a combination of onsite observations, document review, and an analysis of local weather data, Pivot quickly identified a coupling element between a pair of square HSS tubes as the weak link in the structural system. Pivot showed, through initial observations, that the location of the coupler corresponded to the majority of observed panel losses.

Once the issue causing the failure was identified, Pivot reviewed a retrofit designed by the manufacturer of the tracker system and developed an independent retrofit for the tube coupler. Each design was developed to the point that the contractor, who had installed the system, could provide a cost estimate associated with installation of either design. Pivot's retrofit design centered on the idea of a coupler that would provide continuous strength and stiffness across the connection, such that relative twist or displacement between the two coupled members did not occur.

To validate assumptions made in either design, and to develop a comparison of design performance, Pivot recommended that the two coupler designs be tested, and compared to tests of the original coupler. Pivot designed a method to test each coupler retrofit and the original coupler. This test design included a loading protocol, a monitoring system, and a unique test setup which allowed torque, bending and a combination of each to be tested. Pivot’s test design, and completion of 9 independent load tests were completed in less than one month.

Once testing was complete Pivot rapidly processed and discussed testing results. The test results led to the selection of our coupler design for installation.

PROJECT SERVICES:

Failure Investigation

Structural Assessment

Structural Repair

Serviceability Improvements

Load Testing