Snow loads on flat roofs with elevated solar panel arrays - Research results for wind-induced shape coefficients

The installation of solar (or photovoltaic, PV) panels (also arrays) on flat roofs is becoming increasingly popular. Experimental investigations have not only provided qualitative results for snow load distributions, but also quantitative results that enable snow load shape coefficients to be derived for flat roofs with elevated PV arrays. Small-scale water flume tests were carried out to analyse how the presence of PV arrays can influence wind-induced snow accumulations. The laws of physical similarity between model and climatic data were used for this. The tests were carried out at the Institute for Hydraulic Engineering and Water Management at the Technical University of Darmstadt. Recently, design models for snow loads on flat roofs with elevated solar arrays have been published in draft versions of the Eurocode prEN 1991-1-3, currently under review. They are based on regulations soon to be published in a new German National Annex to the existing Eurocode DIN EN 1991-1-3/NA:2019. In this paper it is shown that these draft models are not suitable for every climatic condition. Research results and alternative criteria are discussed on the basis of the investigations.