Analysis Of Dynamic Characteristics Of High-rise Buildings On Asynchronous Sampling

As a means of getting the intrinsic vibration property of the structures,vibrating test and modal identification anal ytic technique has been used.Accompanied with the rapid progress and application of high-rise buildings,plenty of studies on the structural performances have become the focus of attention.Beginning with the application and summary of modal analysis method for high-rise building,a new method for identifying structural modes by using synchronized unknown response signals under ambient excitation is proposed.The central idea of this dissertation can be outlined as follows.Firstly,the paper briefly introduces the development status of field measurement methods for high-rise buildings at home and abroad,then systematically discusses the theoretical research based on asynchronous sampling,specifically discusses the error causes of asynchronous sampling,the principle of signal interpolation and reconstruction,and the time-history alignment method of acceleration signals between different floors.The applied physical significance of this method is analyzed and explained.Secondly,in-situ measurements of two high-rise buildings in Wenzhou and Haikou were carried out by using asynchronous sampling method.Applying this method to measure vibration acceleration signals of several floors under asynchronous sampling conditions.A time domain calibration method for the correlation coefficient is proposed to calibrate the time delay between different sensors on different floors of the building after interpolation and filtering on acceleration signal.To further verify the accuracy of the algorithm,the corrected signals are applied to modal analysis and successfully identify the first three orders of natural frequency and modal shape,and the modal shapes are testified by shape orthogonality and MAC criterion.Lastly,the dynamic characteristics of Wenzhou high-rise building elevator are obtained by field measurement,the interaction mechanism between elevator car and structural vibration response is revealed.The elevator acceleration signal is used instead of floor acceleration signal solve the natural vibration frequency and mode shape of high-rise building,and the error is carried out.The feasibility of using elevators to test the vibration modes of high-rise buildings is discussed.