Dr. Randall Poston, PhD, PE, SE, NAE, Sr. Principal at Pivot Engineers and Neil Armstrong Distinguished Visiting Fellow, held a seminar on Tuesday, October 5th titled, "Wind damage of solar power arrays and required repairs."

Abstract

In 2017 a wind event resulted in the failure of a numerous panels of a newly installed solar power generating facility outside of Buckeye, AZ. The solar array featured a popular single-axis tracker system purportedly 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 was able to quickly identify a coupling element between a pair of square HSS tubes as the weak link in the structural system.

Once the issue causing the failure was identified, Pivot reviewed a retrofit designed by the manufacturer of the tracker system and developed its own 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 providing a combination of torsional and flexural stiffness and strength equivalent to either tube member being coupled, 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.

Once testing was complete Pivot was able to rapidly process and discuss testing results. Upon completion of the tests, Pivot reported the test results to the client leading to the selection of our coupler design being selected for installation.

An internationally recognized expert in structural engineering and member of the National Academy of Engineering, Randall Poston has established himself as one of the preeminent structural consultants in the United States. Dr. Poston has authored and delivered hundreds of papers and presentations related to the structural engineering industry, championed the repair of existing structures for upwards of 30 years, and dedicated his career to advancing the state of structural engineering knowledge.

As past Chair of the American Concrete Institute (ACI) Committee 318 Structural Building Code (2008-2014), he oversaw a monumental effort to  completely reorganize the concrete code, the first undertaking of its kind in the history of ACI. Engineering News-Record (ENR) named him a "Top 25 Newsmaker" of 2014 for his code reorganization leadership and ACI bestowed him with the Henry L. Kennedy Award for this work. Dr. Poston became the 96th President of the American Concrete Institute at the conclusion of the ACI Convention in Quebec City on March 28, 2019.

Neil Armstrong Distinguished Visiting Fellows

2019 marked 50 years since Purdue Engineering alumnus Neil Armstrong’s "one small step" inspired the world towards seemingly limitless human and technological achievement. On that historic occasion, Purdue Engineering launched the prestigious Neil Armstrong Distinguished Visiting Fellows program, which brings highly accomplished and recognized scholars and practitioners to the college to catalyze collaborations with faculty and students.

Fellows are individuals who have been eminently recognized for their impact and achievements in engineering or related disciplines, who collaborate with Purdue Engineering faculty members on research projects and initiatives including new research directions, industry engagement, on-campus and online educational efforts, increasing diversity and inclusion, as well as entrepreneurship. Their selections are based on nominations made by faculty and the proposed impact of their research and visit on Purdue Engineering.