Research On Along-wind Wind-induced Vibration Response And Equivalent Static Wind Load Of High-rise Building And Towering Structure

The research on calculation methods of equivalent static wind load of high-rise building and towering structures is an important part of wind engineering.At present,there are many calculation methods for the equivalent static wind load of a structure,but most methods are based on a single target equivalent and only consider the first mode of the structure.Most methods can only calculate specific responses at specific locations of the structure,but they cannot accurately calculate responses for other locations of the structure.And the equivalent static wind load obtained by different methods is quite different.Research on structural wind-induced vibration response is the basis for research on equivalent static wind load.At this stage,the wind-induced response calculation methods are mainly frequency domain calculations based on Davenport's random vibration theory,which must meet certain assumptions and often hard to get accurate values of the structural resonance response.Therefore,it is necessary to further develop the calculation methods of wind-induced response and equivalent static wind load of the structure.The main research contents and achievements of this paper are as follows:(1)The wind environment parameters and the classical displacement gust load factor(DGLF)method proposed by Davenport were described and according to the idea of gust load factor based on base moment(MGLF)method.The principle of the gust load factor GLF for each response at any position of the structure was given,and derived GLF display expression.The GLF in this paper does not regard the specific response of the structure as the equivalent target.In theory,accurate results of the response at any position of the structure can be obtained.A high-rise building was taken as an example to verify the rationality of the method in this paper,and the limitations of the gust load factor method were analyzed and illustrated.(2)The basic principles of the inertial wind load(IWL)method in China's standards were illustrated.The theoretical difference and influencing factors of IWL method and MGLF method were compared and studied.The influence of various factors on the base moment and base shear response of the two methods were analyzed.The study found that the IWL method only considers the background and resonance contributions of the first mode of the structure,while the MGLF method considers the resonance contribution of the first mode and the background contribution of all modes.The MGLF method results are more reasonable.The calculation of a high-rise building shows that under the same calculation parameters,the base moment and base shear response of the MGLF method were larger than the IWL method,which was the same as the conclusion of the previous theoretical comparison.However,due to the large difference in parameter values of the two methods,especially the resonance response of the Shiotani coherence function used by the IWL method was more than 90% larger than the Davenport coherence function used by the MGLF method.As a result,the equivalent static wind load of the IWL method is larger than the MGLF method.(3)The frequency domain analysis method of wind-induced vibration response of towering structures based on random vibration theory was explained,In order to overcome the shortcoming that it is difficult to accurately obtain the resonance response of the higher-order mode in the frequency domain calculation of the structural response based on the wind spectrum.In contrast,the method of dividing the background and resonance components in the time domain calculation of wind-induced vibration was proposed,and the definition of the background and resonance coupling components in the time domain was also given.Taking a towering lightning rod structure as an example,the frequency-domain method and the time-domain method were used to calculate its wind-induced vibration response,and the results were compared.It is concluded that the division of the background and resonance components in the time-domain calculation of wind-induced vibration response is reasonable,and the resonance response and the background and resonance coupling components given by the time-domain calculation method are theoretically exact solutions.It provides a reference for future research on wind-induced vibration response.