Inversion Research On Wind Load Of High-rise Building Based On Observational Acceleration

Wind load is the main horizontal load of high-rise building. It is also the crucial load for the high-rise buildings structure designing. Field measurement and wind tunnel test are two of the main approaches to obtain the wind load on high-rise building. However, the result of wind tunnel tests are based on scaled models. The results are certainly different between the actual wind load and the wind tunnel tests. Field measurement can more accurately reflect characteristics of wind load on the surface of the structure and the wind-induce response. In field measurement, because of the complexity of working conditions and the limitation of instruments, we can only measure wind pressures at a few of points. Wind load inversion, however, can not only obtain the wind load and its characteristics in a comprehensive way at different stages of the development of typhoon. Thus, it has the basic significance to the safety evaluation of high-rise building structure. Field measurement of wind load on high-rise building cannot always obtain results directly by many reasons, such as non-uniform distribution of wind pressure, building size, et al. However, measuring wind-induced response is relatively easy. Inversion by the measured the wind-induced response of high-rise building is one of the important way to estimate the wind load indirectly.Firstly, this paper introduces coastal field measurement of wind induced vibration of the high-rise building process under typhoon, and analyze the change of the average wind speed, the average wind direction and wind induced response results in the whole process of typhoon. The mode of the structure is analyzed on the basis of the acceleration response.Secondly, the derivation of wind load reversely by wind induced response need to build calculation model. As there are too many floors in high-rise buildings, if using the traditional mass-spring model, the degree of freedom is too large to measure. Building polycondensation simplified model is a simplified method, where multilayer floors reduce to a mass. Under the premise of the simplification of the accuracy of model, this method can greatly simplify structure of degrees of freedom, then it will be convenient to analyze and calculate, it is also convenient to measure. So, the five points bending shear layer model of a high-rise building is established. Quality and stiffness of the simplified model and the actual structure are equivalent, and the dynamic characteristics also follows similarity law. On the basis of the physical parameters of the simplified model, the wind load is inversed then.Thirdly, acceleration response is integrated for obtaining speed and displacement response. Combining with physical parameters of simplified model, the dynamic equilibrium equation of a fluctuating wind load is used to inverse the fluctuating wind load on each mass node of the simplified model. The fundamental frequency of the structure dominate wind-induced vibration of structure.On the basis of the inversion of the wind load, the average wind speed,and the average wind direction, the fluctuating wind speed time history and turbulence degrees of each height can be derived. The results show that longitudinal turbulence intensities are higher than lateral turbulence intensities along the height.Finally, the inversion of fluctuating wind load and average wind load is superposited to be the total wind load. The wind load is loaded on the simplified model, and the wind-induced response time history is analyzed. Both time domain and frequency domain of acceleration response matches well. It confirmed the inversion of wind load correctly...