Impact of Table Size on the Performance of Thermo-Plastic Roofing Systems Under Wind Uplift Pressures

Roofing systems have always been vulnerable to strong wind uplift pressures. Wind forces have dynamic effects on structures, as they change in time and space. Therefore, a dynamic means of evaluating roofing systems is necessary in order to identify the component of the system having the least resistance to wind uplift forces. Although researchers worldwide have conducted tests on roofing structures, they have all used various table sizes, as there is still no standard chamber size for experimental purposes. This paper aims to study the impact of table size on roofing system performance. To achieve this objective, extensive analytical work has been conducted to investigate the performance of roofing systems subjected to wind pressure. Analytical results compared well with those obtained from experimental work, validating the numerical modeling. This paper presents some of these result comparisons. It was found that an increase in table width beyond a certain level, about 3 m for cases considered here, did not significantly change the results, while the rate of fastener load change might be high for a smaller table width. This specific limit depends on the roofing system configuration. Furthermore, a larger membrane width (fastener row spacing) would increase the width of the ideal table. Ideal table sizes were also suggested for various configurations having a TPO (Thermo-Plastic Olefins) membrane and correction factors were eventually developed for different table sizes.