Research On Dynamic Characteristics Of High-Rise Structure Based On Distributed Synchronous Acquisition

In this paper,the dynamic characteristics of high-rise structures with stiffness and mass mutation at the top are studied.The means of theoretical analysis,numerical simulation,field test and modal parameter identification and tracking method based on distributed synchronous acquisition are used to explore the vibration characteristics of high-rise structures under operation stage and the influences of high-order modes to structures,reveal the mechanism of excessive vibration of catastrophic structure,and long-term monitoring system has been established to study the vibration characteristics of high-rise structure under two different vibration modes.The distributed synchronous acquisition method is innovated and the synchronization accuracy evaluation standard is established.In order to identify the modal parameters of the actual high-rise structure,it is necessary to obtain high-precision synchronous vibration data.This paper proposes a data synchronization method based on GPS-second pulse self-compensation program to implement distributed synchronous acquisition on high-rise structures.The feasibility of modal identification by covariance-driven random subspace method is analyzed by theoretical derivation and the data synchronization criterion based on this method is proposed.The modal identification effect of the distributed synchronous acquisition method and of the centralized acquisition method is compared by the modal test of the high-rise structure on the site,and the feasibility of the distributed synchronous acquisition method proposed in this paper is verified.The modal test of the high-rise structure is carried out and the distributed synchronous acquisition method is applied.In this paper,the distributed synchronous acquisition method is applied to obtain synchronous vibration data in the modal test of KK Fund Finance Center and the Covariance-Driven random subspace method is used to identify modal parameters.The measured vibration modes directly reflect the obvious abrupt phenomena of the abrupt structure.Based on the model data,the cumulative contribution coefficient of modal displacement is calculated and the distribution characteristics of higher-order modal contribution between catastrophic structure and main structure are obtained.The distribution law is consistent with the energy contribution and root mean square response contribution of the measured results.By analyzing the theoretical formula of the contribution index of mode displacement,it is found that the abrupt change of mode shape is the main reason for the greater contribution of higher modes to the vibration of abrupt structure.A long term monitoring system for KK financial center has been established and long-term data analysis has been carried out.In order to enhance the accuracy and persuasiveness of the conclusions obtained from the modal test,a long-term monitoring system is built to monitor and automatically track the modal parameters of KK Financial Center.The system captures the structural vibration characteristics under the action of typhoon "mangosteen" and of the normal conditions.The results show that under the action of typhoon,the whole structure takes part in vibration mainly by first-order modes,and the influence of higher-order modes can be neglected.Under normal wind,the main structure takes part in vibration mainly by high-order modes,and the main structure takes part in low-frequency modes.The comparison of the two working conditions shows that the influence of higher order modes is the cause of the excessive vibration of the mutant structure.