Consequences Related to Joint Construction Methods in PV Support Structures—Experimental and Numerical Considerations

Abstract

The need to reduce fossil fuel extraction has led to increased demand for alternative energy production systems. As a consequence, solar, water, and wind energy production systems are becoming widespread. Cold-formed thin-walled steel profiles have become popular in photovoltaic support systems for economic reasons. In this study, analytical methods recommended for thin-walled structures were used with the aim of validating the authors’ earlier experimental results against analytical ones regarding deflections and failure force. A secondary objective was to develop a computational model which is suitable for application in engineering practice. Finally, the novelty of the study lies in the analysis of the presence and intensity of the diaphragm effect. This article compares two PV support structures on a natural scale. The only difference between the analyzed structures is the presence of an additional steel angle in the purlin–rafter joint; its absence caused a significant (by over 30%) decrease in load capacity and an increase in deformation. In the experimental tests, the ultimate load for structure K-1 ranged from 20.5 kN to 26.6 kN (exact failure load was not possible to determine), while it was 38.9 kN for structure K-2. The safe method of load capacity assessment was proposed along with the implementation of 7-degree-of-freedom analytical model. Additionally, the geometrically and materially nonlinear analysis with imperfections enabled detailed investigation of both structures’ failure mechanisms.