Application of numerical models to determine wind uplift rating of roofs

Wind uplift rating of roofing systems is based on standardised test methods. Roof specimensrnare placed in an apparatus with specified table size (length and width) then subjected to the required windrnload cycle. Currently, there is no consensus on the table size to be used by these testing protocols in spiternof the fact that a table size plays a significant role in evaluating the performance. This paper presents arnstudy with the objective to investigate the impact of table size on the performance of roofing systems. Tornachieve this purpose, extensive numerical experiments using the finite element method have been conductedrnto investigate the performance of roofing systems subjected to wind uplift pressures. Numerical resultsrnwere compared with results obtained from experimental work to benchmark the numerical modeling. Requiredrntable size and curves for the determinations of appropriate correction factors are suggested. This has beenrncompleted for various test configurations with thermoplastic waterproofing membranes. Development ofrncorrection factors for assemblies with thermoset and modified bituminous membranes are in progress.rnGeneralization of the correction factors and its usage for wind uplift rating of roofs will be the focus of arnfuture paper.