HFFB Technique-based Wind-induced Vibration Analysis Of High-rise Buildings Considering The Mode Coupling Effect

High-frequency force balance(HFFB)wind tunnel test is one of the main ways to determine the wind load and structural wind-induced vibration effects of high-rise buildings.With the increasing construction height of high-rise buildings and the increasingly new structural forms,more and more super high-rise buildings have three-dimensional modes.Based on the HFFB technology,this paper studies the wind-induced response analysis method of super-tall buildings considering the three-dimensional mode coupling effect,including:(1)The method of eliminating the multi-modal amplification effect of the aerodynamic loads measured by the model-balance system is studied.Decoupling the bending moments around the two horizontal principal axes measured by the balance,and based on an intelligent search algorithm,the dynamic parameters of the model-balance system are accurately identified.On this basis,the aerodynamic load is then corrected.Taking Guangzhou East Tower as a case,the effectiveness of the method was verified.(2)A wind-induced response analysis method considering the three-dimensional mode coupling effect is studied.Firstly,the peak displacement response and the peak acceleration response at the top of the structure are obtained based on the Complete quadratic correlation(CQC)method.The mutual power spectral density of the two horizontal principal axis bending moments and its correction are considered in this process.The principle of the constant proportion of each component in the generalized mass gives the matrix of modal distribution coefficients,and the mode matrix and modal force spectrum density matrix considering the modal coupling effect are constructed.On this basis,by comparing the distinguishing and not distinguishing background response and resonance response methods,the influence of background response and resonance response on the total response is analyzed.The peak base bending moment response considering the modal coupling effect is derived according to the relationship between the square root bending moment response and the square root displacement.The need to combine case analysis methods.(3)The equivalent static wind load calculation method considering 3D mode coupling effect and the correlation between background and resonance response is studied.Aiming at the problem that the existing equivalent static wind load calculation method ignores the correlation between background and resonance response,the calculation method of equivalent static wind load considering the correlation between background and resonance response is proposed,and the mathematical formula is strictly derived.Based on the two building cases of Guangzhou East Tower and Guangzhou Hitachi Elevator Tower,the effectiveness of the method were verified.Based on the research results of the base bending moment response considering modal coupling effect,the equivalent static wind load considering the modal coupling effect is obtained.