Numerical Simulation Of Effects On Wind Loads On The Roof Of Low-rise Gable-roofed Buildings

The coastal regions of China are those areas that typhoon often visits. Previous wind disaster surveys indicate that most destroyed buildings in the disaster are low-rise buildings. Therefore it is of great significance to investigate the wind-load distribution characteristics of such buildings and accordingly find out the corresponding wind-resistant ways.In this dissertation, numerical simulation techniques are employed to study the wind-induced pressure distributions on the roof of gable roofed buildings that with different height-width ratios and different roof overhangs and different parapets. On the basis of the existing research achievement, the basic equations and numerical discretization and solution approaches for turbulent wind flow based on the averaged Navier-Stokes equation and the k-e turbulence model are established. As a numerical example, a group of building models that were tested in a full-scale experiment are first considered. The obtained numerical results are compared with those of the full-scale experiment and the validity and accuracy of the numerical simulation are demonstrated. With the above full-scale building model as a basis, a series of models with different roof pitches and different height-width ratios are used to further study the effects of roof pitch and height-width ratio. Through parametric analysis and comparison practical formula for determination of the shape factors on the building roof are established. The obtained results indicate that with the increment of the roof pitch the magnitude of the windward roof pressure tends to decrease and that of the leeward roof pressure tends to increase. The recommended roof pitches are 15°~25° . The magnitude of the windward roof pressure tends to increase with the increment of the roof pitch.Numerical simulation and parametric study are then conducted to investigate the wind pressures on the low-rise gable roofed buildings with different forms of roof overhang and parapet. The study emphases are put on the effects of the form and width of roof overhang, the form and height of parapet and the roof pitch. Through the parametric study it indicates that the right-angle overhang and surrounding parapet form with the overhang length in a proper range is a better choice of low-rise gable roof buildings for resistance of wind pressures. In general the parapet height with a normal size within 0.6m to 1.2m have no considerable effects on the roof pressures.