| Super high-rise structures are vulnerable to wind load due to their slenderness ratio and high flexibility,which will cause deformation and endanger the safety of the structure.Through real-time monitoring,structural damage can be found in time,and emergencies can be early warned to reduce economic losses.Therefore,real-time dynamic deformation monitoring is particularly important.In this paper,based on GNSS-RTK,the real-time dynamic deformation monitoring of super high-rise structures under wind load is carried out,and the data filtering algorithm is systematically studied.The vibration frequency and amplitude of the structure are further analyzed with the data after noise reduction.The main research contents and innovations are as follows:(1)In order to analyze the background noise and instrument accuracy of GNSS receivers,two GNSS were used for stability test.The results show that the displacement amplitude obtained by the stability test is basically within 10 mm,which meets the accuracy requirements of the equipment labeling background noise is divided into low frequency random noise and high frequency white noise by spectrum analysis.(2)Aiming at the limitation and shortage of traditional evaluation index in wavelet threshold denoising,a comprehensive evaluation index based on combination weighting method is proposed,and the accuracy and universality are simulated and verified by engineering signals.The results show that the comprehensive evaluation index can effectively overcome the defects of single weighting method and make the weight distribution more scientific and reasonable.Compared with previous methods,this method from the single index component selection to decomposition scale and wavelet basis function optimal value determination process reflects the physical meaning is more clear,higher accuracy,better universality.(3)In order to give full play to the advantages of multiple filtering and make up for the shortcomings of single filtering,a joint denoising algorithm(ICEEMDANCEIWTD-SG)based on the judgment criteria of variance contribution rate,correlation coefficient and zero crossing rate is proposed,which is verified by simulation signals and engineering examples.The results show that the proposed joint denoising algorithm has the best noise reduction effect compared with S-G filtering,WTD,and CEIWTD,with the smallest root mean square error,the highest signal-to-noise ratio and the largest correlation coefficient,which proves the effectiveness and superiority of the proposed algorithm.The vibration characteristic information of the structure is also successfully extracted in engineering application,which is helpful for subsequent vibration analysis and has high engineering value.(4)In order to study the influence of different wind loads on the amplitude and vibration frequency of super high-rise structure,the GNSS monitoring data of Tianjin Broadcasting and Television Tower under different wind loads were analyzed,and compared with the results of accelerometer,empirical formula and finite element simulation.The results show that the dynamic deformation monitoring based on GNSS can effectively identify the vibration characteristics of super high-rise structures under wind load.Under the action of strong wind,the amplitude of the structure reaches more than 5 cm,and the first-order vibration frequency in the x and y direction of the structure is 0.1583 Hz,which is 0.19% different from the accelerometer and the finite element results.Under the action of breeze,the x and y direction differences are 0.88% and0.19%,respectively.Under the above experimental conditions,the vibration frequency identification results are within the range of empirical formulas. |
PDF Full Text Request