Research On GNSS Dynamic Monitoring And Data Analysis Method Of High-Rise Buildings

High rise buildings will inevitably be affected by environmental corrosion,structural fatigue,as well as the coupling effect of long-term load and extreme load,which will cause the performance degradation of the structure,damage accumulation and reduce the disaster resistance of the structure.Therefore,structural health monitoring technology has been well developed and widely used to evaluate the bearing capacity and durability of the structure.In the field of structural health monitoring,the displacement information of the structure deformation structure is the basic support to calibrate the mechanical model of structure.GNSS is an important dynamic monitoring technology of high-rise buildings,it can directly measure the three-dimensional displacement of monitoring points.However,due to the influence of external environment and receiver noise,there are some errors in GNSS dynamic monitoring data.Accelerometer has the advantages of high sampling rate and high precision,which is an important monitoring method in the vibration monitoring of building structure.Compared with the GNSS positioning technology,accelerometer can not accurately obtain the quasi-static displacement of the structure,so there are some limitations in the application of the accelerometer for the dynamic monitoring of the structure.It is very important to get the deformation of the structure accurately and to mine the hidden structure information from the monitoring data with noise.In this study,GNSS and accelerometers are used as monitoring technology,the following aspects are studied for the dynamic monitoring and data analysis methods of high-rise buildings:(1)This paper systematically summarizes the application progress of GNSS monitoring technology for the dynamic monitoring of high-rise buildings,and introduces the application progress of multi-sensor structural dynamic monitoring technology based on GNSS and accelerometer.This paper reviews the commonly used dynamic monitoring data analysis methods,and analyzes the application status,advantages and disadvantages of data analysis methods such as Fourier transform,wavelet transform,empirical mode decomposition(EMD).(2)In order to solve the problem of the difficult selection of reference stations in the city and save the cost of the monitoring,a combined high-low rate GNSS high-rise building dynamic monitoring method is studied based on the GNSS single-epoch relative positioning and time-differenced positioning.For this method,only high-rate GNSS receiver is needed in the monitoring station,and the reference station can adopt low-rate receiver similar to city CORS station to save the cost of the monitoring.In this study,the shaking table simulation data and wind vibration monitoring data of the high-rise building are used to compare the method with single epoch relative positioning method,precise point positioning method and accelerometer method.The feasibility and superiority of the method is verified in the monitoring of wind-induced response of high-rise buildings.The results show that the method can not only effectively monitor the quasi-static and vibration displacement of high-rise buildings,but also can save the cost of the engineering monitoring.(3)Aiming at the problem that the GNSS monitoring technology can not recognize the high-frequency information of the structure and is not sensitive to the weak deformation,the dynamic monitoring method of the high-rise building integrating GNSS and accelerometer is studied.Based on the random decrement technology and damping ratio identification technology,the fusion data are analyzed from the aspects of vibration mode identification,signal denoising,vibration signal extraction,random attenuation signal acquisition,damping ratio identification and quasi-static displacement monitoring,etc.The results show that the dynamic monitoring method based on GNSS and accelerometer can not only retain the low-frequency and high-frequency deformation information of the structure,but also effectively remove the high-frequency noise of the GNSS monitoring data,and it can improve the sampling rate,accuracy and reliability of the displacement monitoring data.This method is verified to be effective in the dynamic monitoring of high-rise buildings.(4)Research on the analysis method of GNSS dynamic monitoring data of high-rise buildings.In view of the problem that the dynamic characteristics of high-rise buildings are not obvious due to the monitoring noise of GNSS,a more effective method to extract the dynamic characteristics of high-rise buildings is studied.On the basis of summarizing the empirical mode decomposition and wavelet analysis method,aiming at the GNSS dynamic monitoring data with low signal-to-noise ratio,this paper studies a method to extract the dynamic characteristics of high-rise buildings combined with EEMD and wavelet analysis.The validity of the method is verified by vibration simulation experiment,GNSS shaking table simulation experiment and dynamic monitoring experiment of the high-rise buildings.The results show that this method has better ability of vibration signal extraction compared with the traditional EEMD method and wavelet analysis method.It can be applied to the GNSS dynamic monitoring data analysis of high-rise buildings.