Sustainability of Industrial Building SSMR through Experimental and Analytical Study under Wind Uplift Load

Standing Seam Metal Roofs (SSMRs) are widely used in the construction of industrial buildings, and their structural characteristics are rapidly being changed in order to improve the parameters of heat insulation and waterproofness. However, newly employed SSMRs did not account for a potential structural instability under strong winds by considering the multi-function of SSMRs. In this study, three different types of new SSMRs were chosen as specimens and were used in full-scale experiments, which were performed using the cyclic wind uplift method based on ASTM E1592 regulations. In contrast to a previous study in which the ultimate failure of the roof under wind pressure corresponded to seam line failure due to panel deflection, in this study, the experimental results show that seam separation was induced by a mid-clip rupture. It is verified that the behavior of the mid-clip plays a significant role in the overall performance of SSMRs under wind uplift loading. The objectives of this study were to (i) understand the structural performance and failure mode of new SSMRs under wind uplift pressure, as this condition is closest to reality, and to (ii) quantify the structural sustainability, which can be applied to risk-management practices through the established performance evaluation. It is expected that the present research results may provide future directions for improving the test standards, design guidelines, and risk-management practices.

The interplay of wind and uplift facilitates over-water flight in facultative soaring birds

Flying over the open sea is energetically costly for terrestrial birds. Despite this, over-water journeys of many birds, sometimes hundreds of kilometres long, are uncovered by bio-logging technology. To understand how these birds afford their flights over the open sea, we investigated the role of atmospheric conditions, specifically wind and uplift, in subsidizing over-water flight at a global scale. We first established that Δ T , the temperature difference between sea surface and air, is a meaningful proxy for uplift over water. Using this proxy, we showed that the spatio-temporal patterns of sea-crossing in terrestrial migratory birds are associated with favourable uplift conditions. We then analysed route selection over the open sea for five facultative soaring species, representative of all major migratory flyways. The birds maximized wind support when selecting their sea-crossing routes and selected greater uplift when suitable wind support was available. They also preferred routes with low long-term uncertainty in wind conditions. Our findings suggest that, in addition to wind, uplift may play a key role in the energy seascape for bird migration that in turn determines strategies and associated costs for birds crossing ecological barriers such as the open sea.