The Influence Of Heterogeneous Terrain Wind Loads Interference Effects On Flat Roof

With the rapid development of economy and city construction in China, lots of industrial workshops, stadiums and exhibition centers have been built. Most of these buildings are long-span roof structures for which wind load is the main dominant load.Long-span roof structures are completely in the near surface boundary layer for their lower building height so that the interference effect from other similar buildings is significant. There are many influence factors of the interference effect, and various kinds of factors have great variability. In this paper, the interference effect of wind load on pieces of industrial plants is studied. These buildings are often constructed in the suburbs, as a result, for the strong wind from city center, the landform will change into suburbs with flatter landform from urban center with rougher landform, showing a inhomogeneous terrain feature. Therefore, under the condition of non-uniform landform, the research has great significance on interference effect of wind load for single plant and groups of industrial plants.On the basis of Chinese code for the design of building structures, two types of atmospheric boundary layer with homogeneous terrain were simulated in wind tunnel, including rough urban terrain and flat suburban terrain. At the same time, the wind load characteristics of single flat roof structure were researched under the condition of the two homogeneous terrains. In addition, the atmospheric boundary layer with inhomogeneous terrain was simulated from rough topography to flat landform, and the wind load characteristics of single flat roof structure were researched in this case. The main conclusions are:under the condition of two different types of homogeneous terrains, the flatter the topography type, the larger the mean wind pressure coefficient and extreme wind pressure coefficient of structure. Supposing the total static pressure of rough and uniform landform as a reference in none-uniform terrain, with gradual development of the flat terrain at downstream, the model’s mean wind pressure coefficient and extreme wind pressure coefficient decrease gradually. When the model lies in the fully developed position at downstream, the mean wind pressure coefficient and extreme wind pressure coefficient for roof reduce about 20% than that of rough terrain.Based on studying the wind pressure characteristics of the single flat roof under the condition of uneven terrain, the interference effect of wind load on the flat roof of building complex was studied. Taking the arrangement of 3 rows and 1 column of building groups as a research object, the influence of building space and building location from the change point of terrain on the interference effect of architectural complex was studied. The main conclusions are:when model space is more than 20 centimeters, the mean and fluctuating wind load on the roof downstream grows with the increase of building space. And in non-homogeneous terrain, the effect of building space on the mean wind load of roof is significant; when model space is smaller and the interference effect between models becomes obvious, the farther the distance between model and the change point of terrain, the larger the mean and fluctuating wind load of disturbed model downstream; when model space is larger and interference effect weakens, the farther the distance between model and the change point of terrain, the smaller the mean and fluctuating wind load of disturbed model downstream.