The Fine-analysis Method For The Wind Effects Of Super-tall Buildings Considering The Distribution Features Of Wind Speed And Direction

The super-tall buildings serve as landmarks of modern city, the influence of which with respect to space and time is considerable. This kind of structure is designed by considering the wind loads as the main control load due to its large flexible, small damping and sensitivity to wind. Calculated based on the basic wind pressure given explicitly by the load code, the design wind load is overly conservative, without considering the variation of wind direction of wind speed. That results in unnecessary waste in the structural wind-resistance design. Putting the distribution probability characteristics of wind direction of extreme wind speed and extreme loads(or responses) into consideration at the same time should be the most appropriate method to assess wind effects. For this, based on the detailed analysis of wind climate, this paper investigates the wind-induced responses and the wind-induced loads of the high-rise building considering the distribution characteristics of wind speed and direction.The main work and conclusions of the full paper are as follows:1. Based on the multiplication theorem, this paper first introduces a concept of wind direction frequency to consider the difference between sample size of all directions, and then constructs the joint distribution probability models of the wind speed and direction corresponding to the Gumbel distribution, the three parameters Frechet distribution and the three parameters Weibull distribution, then giving the optimal distribution model of Guangzhou and Shenzhen. The weighted average method is used to process the measured hourly wind speed and direction before sampling in modeling to consider the correlation between wind speed and direction, so that the modeling results tend to be more reasonable;2. This paper not only deduces the expressions of the changing rate of the hourly wind velocities and hourly wind directions for Guangzhou and Shenzhen, but also carries on the preliminary analysis comparison for their statistical characteristics in the different areas. The results show that the two statistics have different degrees of sensitivity to different regions, the changing rate of the hourly wind velocities is much more sensitive than the changing rate of the hourly wind directions. The paper speculates that they are related to the climatic zone, thus not recommending adopting unified formulas;3. Up-crossing method is used to study the wind effects of a particular high-rise building, and compared with Upper bound method where the effect of wind direction doesn’t put into consideration and Sector design speed method. Studies show that Up-crossing method is better in theory, and can reflect the influence on final structural responses, considering the distribution characteristics of the extreme value of wind speed and loads(or responses) more effectively and accurately;4. This paper simplifies Up-crossing method for engineering application based on a careful analysis of its basic principle, accuracy and applicability. And the comparison analysis shows that the simplified Up-crossing method and Up-crossing method are equally accurate.The last part summarizes the deficiencies and prospects the further research problems of this paper.