A wind load design method for ground-mounted multi-row solar arrays based on a compilation of wind tunnel experiments

Abstract

This paper presents a concise method for determining the design wind loads for multi-row ground-mounted solar arrays, including both static and dynamic wind load coefficients compatible with the ASCE 7, based on a compilation of wind tunnel experiments conducted by RWDI using rigid pressure models. The proposed method addresses the well-established shortcomings of the ASCE 7–16 definition of ‘rigid structure’ based on the frequency of 1 ​Hz when applied to such arrays and the need identified in SEAOC PV2 (2017) that ground-mounted arrays with numerous repetitive structures shall consider vortex shedding and consequent dynamic resonant effects. Comparisons to other sources available in the technical literature have been made where possible, which are largely satisfactory, and an illustrative example is provided to assist practitioners in applying the proposed method. It is important to note that the method and data presented in this paper assume that wind-induced deflections are small, and thus, the structure is not flexible; flexible structures such as unrestrained single-axis trackers are also prone to aeroelastic effects and torsional instabilities, which are beyond the scope of this paper. Sources of uncertainty are discussed and, in an effort to minimize these uncertainties when predicting design wind loads, it is the authors’ hope that the dataset presented herein be augmented by other contributors to form the basis for codification.