Experimental Research On Wind Field And Wind Effect Of High-rise Buildings Under Typhoon

Typhoon is part of the biggest natural disasters affecting human society.The reasons of structures damaged and destroyed by typhoons such as buildings,roads and bridges are important causes of human society's property losses.With the rapid development of China's economy and the acceleration of urbanization,high-rise buildings with superior flexibility,small damping and wind sensitivity as their main structural features have rapidly increased in volume.Wind load and wind-induced response are the key control factors for the safety and serviceability of high-rise building structures.They have become the fundamental indicators of wind-resistance design and an essential direction for wind engineering research.The research goal of this paper is to make new progress in the prototype measurement of high-rise buildings and the experimental data processing methods,and to obtain the wind field characteristics and structural vibration response characteristics of high-rise buildings in coastal areas under typhoon conditions.Based on the theoretical analysis of the wind field and wind effect prototype measurements in high-rise buildings under typhoon,the understanding of the dynamic characteristics and wind-induced response characteristics of super-tall buildings has been deepened.The main method applied in this paper is to carry out prototype measurement and theoretical analysis on the basis of field research.This article mainly relies on a National Natural Science Foundation project to conduct research on the wind effect and existing high-rise building wind effect measurement research under the typhoon.The specific content is:Firstly,the status and progress of research on wind field and wind-induced responses of high-rise buildings are introduced.The basic theory of wind characteristics and statistical analysis methods of the atmospheric boundary layer is briefly described.Secondly,the wind field and wind effect measurements were performed in coastal areas such as Wenzhou City,Zhejiang Province.The typhoon wind field and wind effect measured data of high-rise buildings were obtained.The typhoon wind field characteristics at the top of high-rise buildings under urban wind environment in coastal areas was analyzed,including mean wind speed and wind direction,turbulence intensity,gust factor,crest factor,the turbulence integral scale,fluctuating wind speed power spectrum.The characteristics of high-altitude wind fields and their changing roles during and after the typhoon landfall were obtained.At the same time,the turbulence characteristics and laws of high-rise buildings under different typhoons were compared and analyzed.Thirdly,based on the data obtained during the impact of Typhoon Morakot in 2009,the characteristics of the wind field within a height of 100 m under different wind conditions in Cangnan County were further analyzed,and the laws of wind field parameters varying with height were obtained.Fourthly,based on the measured data of high-rise buildings under many typhoon wind fields and wind-induced vibrations,the modal parameter characteristics such as frequency,vibration mode and damping ratio of the building are analyzed.The frequencies and vibration modes are relatively close to specification,but the mode damping ratio is quite different.According to the hypothesis of the structural damping ratio in this paper,the law of the damping ratio of the building structure with frequency is analyzed in depth,and the validity of the empirical formula for calculating the structural damping ratio based on the frequency is demonstrated.Fifthly,according to the distribution characteristics of the wind field and the fluid-solid coupling effect of the building structure,the relationship between the aerodynamic damping ratio with reduced wind speed,acceleration of the structural vibration is mainly discussed.A comprehensive comparative study of the aerodynamic damping ratio and its influencing factors was performed under different typhoons.This paper obtains a prototype measurement study on wind field characteristics and wind effect characteristics of high-rise buildings under different geography environments in the southeastern coastal regions.It gives a scientific basis and theoretical reference for wind-resistance design of high-rise buildings in coastal areas of China.