Field Measurement Research On Wind Resistance Of High-Rise Buildings In Coastal Areas

With the application of lightweight and high strength material in civil engineering, the modern high-rise buildings tend to be soft and with low-damping characteristics. Vibrations of high-rise building in the strong wind may cause large plastic deformation to structures, especially the damage of building envelopes occur from time to time. As a result, wind load caused by strong winds are usually become the main control loads in designing such structures. In China, many typhoons landed in southeast coastal areas every year, causing a lot of damage to houses and other structures, including threatening the security of the coastal high-rise buildings and the comfort of residents living there. Therefore, it is necessary to systematically research the wind effects of high-rise buildings in coastal areas during typhoon.Field measurement is one of the main methods to study on structures of wind resistance. In this paper, three high-rise buildings designated as Building A, Building B and Building C in the coastal areas of Xiamen are selected as the field measurement base, and a long-term and systematical research on wind effect of high-rise buildings is carried out there. The research includes wind field measurement on the top of the buildings, wind pressure measurement on building surfaces, acceleration measurement of different floors, as well as the glass stress measurement of insulting glass caused by wind. After several years of monitoring during typhoon landing period, rich supply of measured data was obtained and some effective wind-research method in field measurements is formed.Wind characteristics on the top of high-rise buildings was analyzed based on the wind field data from five typhoons, including the mean wind speed and direction, turbulence intensity, gust factor, turbulence integral scale and wind spectrum of fluctuating wind speed. Among them, the wind on top of the three buildings were synchronously measured during Typhoon "Usagi", and the wind characteristics and the correlation of wind speeds on top of the three buildings are studied for comparative purpose. The wind speed measured during typhoons tends to exhibit non-stationary property. In this paper, an improved method was proposed to extract time-varying mean wind speed for the non-stationary wind model, and the wind characteristics of the measured data was analyzed using non-stationary wind model. Results show that the non-stationary wind model is more reasonable in estimating wind turbulence of the measured wind data.Based on the wind pressure data measured from multi-points on the 33 th floor and the 17 th floor of Building C, characteristics of each measuring point was analyzed, including the pressure coefficient of each measuring point, the probability distribution characteristics of fluctuating wind pressure, peak factors, power spectrum and correlation of the fluctuating wind pressure. Studies have shown that: when the wind direction of the selecting samples is relatively stable, there is few differences in wind pressure coefficient between each 10 min sub-samples, but the location of the measuring point and the probability distribution of the fluctuating wind pressure have some important influences to wind pressure coefficients. With the same guarantee rate, the peak factor of the measured pressure is greater than that based on the assumption of Gaussian distribution. The aerodynamic admittance function of fluctuating wind pressure in the windward side agrees with the exponential decay curve proposed by Kawai. And the correlation coefficient of wind pressure between the windward measuring points is greater than that of the leeward side, the relationship of the coherence function values averaged by frequency and the distance of measurement points can be modeled by a set of exponential function.Wind tunnel test of Building C was conducted under wind exposure conditions of category A and B, and then wind pressure distribution on the surface of the building were analyzed and the shape coefficient of each surface under the two exposure condition categories were provided. By comparing the results with the measured pressure wind tunnel test results, it is found that the average pressure coefficient between the obtained results are basically the same, however the pulsation of some measuring points in field measurement are strong, which might lead to higher peak pressure coefficient.Through the obtained wind-induced acceleration response of Building C in 6 different floors during typhoons, the first six natural frequencies and second translational modes of both directions are identified, as well as the relationship between the R.M.S acceleration response and the mean wind speed. This paper established a reasonable 3-D finite element model and its results of modal analysis are very close with the measured results. In addition, a time-history analysis, based on the results of a 2-D wind field simulation under condition category A, is carried out to analyze the along-wind response of the structure with the excitation of wind pressure time series. The calculated results agree well with those based on the load code of China, and are also close to the measured results.Insulating glass curtain wall is the external structure often used in high-rise buildings and the insulating glass under wind loads would mainly have ben ding deformations. In this paper, pressure loading test of insulating glass curtain wall is conducted using the wind-resistant detection equipment of curtain wall, and a field measurement research on Building C during typhoon is carried out to analyze the wind-induced stress of insulating glass. Combined with the construction features of the insulating glass and its bearing characteristics, a simplified method and a finite element analysis method are proposed to analyze the bending performance of insulating glass units through theoretical analysis.