Measurement Of Typhoon Wind Effect And Wind Tunnel Test Study In Super-high-rise Buildings

With the development of economy and technology,a large number of high-rise/supertall buildings have emerged in coastal areas of China.These buildings are sensitive to wind loads because of their low fundamental frequency and large flexibility,and wind resistance design is a key issue in their design and construction as well as operation and maintenance.The wind effect of high-rise/ultra-high-rise buildings under strong/typhoon action has been a hot issue in the field of structural wind engineering;an in-depth study of this issue has important theoretical significance and practical engineering value for developing and improving structural wind engineering theory and guiding the wind-resistant design of towering and complex wind-sensitive structures such as ultra-high-rise buildings.In this paper,two basic methods,field measurements and wind tunnel tests,are used to study the structural dynamic characteristics and wind-induced response characteristics of supertall buildings,focusing on several issues that are still weak in the existing research in the industry,such as the variation characteristics of modal parameters with amplitude of towering buildings under medium and high amplitude vibration and the influence of Reynolds number（Re）effect on wind effect of supertall buildings with curved cross-section in a large range of levels.Firstly,Zhuhai Center（330m）,the tallest building in Zhuhai,was selected as the research object in this typhoon-prone area of Zhuhai,and a platform was established to measure the typhoon wind effect of super-tall buildings,which covers the structural acceleration/velocity response and the wind pressure on the building surface.Based on this platform and the Lidar profiler,we conducted simultaneous monitoring and analysis of the wind effect characteristics of the building during the impact of Typhoon“Cempaka”in South China in 2021.The variation patterns of the mean wind speed,mean wind direction,gust factor and turbulence intensity of the wind field over the building were investigated;the temporal variation of the wind pressure at each measurement point at each center and corner position of the 56F curtain wall of the building,the non-Gaussian characteristics of each measurement point,the pulsating wind pressure spectrum in the specific incoming flow direction and the wind pressure correlation at each measurement point were discussed;the structural dynamic response characteristics of the building were also analyzed,including its acceleration with wind speed The structural dynamic response characteristics of the building were also analyzed,including the variation of acceleration with wind speed,the comparison of modal frequencies with finite element results,the modal share of each order and the amplitude dependence of modal parameters.The results show that the extreme negative pressures at the corners of the building are larger than the extreme positive and negative pressures at the adjacent central locations,and the probability distribution of the negative pressures shows obvious non-Gaussian characteristics,while the positive wind pressures seem to follow a normal distribution.Vortex alternating shedding was observed on both sides of the building.The power spectrum results for the modal frequencies agree well with the finite element results for both,with the first order advective mode dominating the entire response.The inherent frequency decreases with increasing response amplitude,showing a clear dependence,while the damping ratio fluctuates with the response with increasing amplitude.Secondly,based on the measured response data of five super high-rise buildings under the action of Super Typhoon“Mangkhut”and Strong Typhoon“In-Fa”,The frequency and damping ratio of the first two basic modes of the super high-rise building in the large amplitude（the vibration amplitude is up to 20gal）are studied.The results show that the trends of the RDT and BSDA methods are generally consistent.The frequency of a building structure will decrease with the amplitude increases and then remain unchanged,and the damping ratio will increase and then decrease with the amplitude increases.Buildings with dampers have a relatively large fluctuation range of damping ratios.The“critical tip drift ratio”of each building is within the range of 10^-4-10^-5,which is in line with professor Tamura’s previous research conclusion;and comparison of the specifications,the frequency of each building is most consistent with the prediction model proposed by Professor Tamura,and the damping ratio is most in line with the prediction model in PEER/ATC-72-1 specification,but there are certain fluctuations.Finally,this paper integrates field measurements and wind tunnel tests to study the wind effect of the 330-m Zhuhai Center Building with a curved cross-sectional shape,focusing on the influence of the variation of Reynolds number on the wind effect characteristics of the building.Dependence of Strouhal number（St）,pressure,base force and wind-induced structural response upon Reynolds number from 5.0×10⁴to 3.8×10⁷is analyzed.Results suggest that with the increase of Re,Strouhal number firstly increased and then leveled off,mean wind pressure on the leeward side of the building’s upper portion decreased significantly and mean drag force as well as fluctuating lift force at the upper portion increased moderately,while both the along-wind and cross-wind components of structural response increased slightly.Despite the above variations,results through wind tunnel tests with Reynolds number exceeding 1.5×10⁵basically agreed with those from field measurement.In addition,the fluctuating pressure around the separation points became distinctly stronger for cases with larger Reynolds number values,which reflects the sensitivity of separation phenomenon to both Reynolds number and geometric details of the building’s cross section.In summary,the relevant research results of this master thesis bring a referenceable basis for the assessment of wind effects in supertall buildings,and provide important reference information and engineering practice value for guiding the wind resistance design of supertall buildings.