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Research on the Condition Assessment of Bridge Based on the Chaotic Time Series

Author: WuJiaoMei
Tutor: YuLuSong
School: Lanzhou Jiaotong University
Course: Disaster Prevention and Reduction Engineering and Protective Engineering
Keywords: Bridge Health Monitoring Time Series Chaos Pretreatment State assessment
CLC: U446
Type: Master's thesis
Year: 2011
Downloads: 61
Quote: 0
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Abstract

The bridge structure by the natural environment in the course of the increase in traffic volume, vehicle load and the combined effect of the material internal factors, defects and diseases occur over time, reduce the durability of the structure, bearing capacity decreased, affecting the use of the bridge life. Currently, the assessment of the status of the existing bridge structure has become a hot research directions in the field of civil engineering. Bridge load test positive detection for safety assessment Newbridge put into use before or bridge damage by accident, however, the need to interrupt the traffic load test, repeat to spend a lot of manpower, material and financial resources, and other costs are relatively high, and only for a period of time, there is poor timeliness. Bridge remote monitoring is able to overcome the above drawbacks, with secure, real-time, continuous, and timely early warning and forecasting characteristics. With the rapid development of technology for structural health monitoring, testing the accuracy of information to improve conditions improve and field testing, to assess the state of the bridge structure to provide the necessary support. This article aims to nonlinear dynamic behavior of the bridge structure, mastered a lot of monitoring information based on the extraction system characteristics indicators to achieve the status of the existing bridge structure assessment study. Of this research work is mainly reflected in the following aspects: (1) to collect information on the assessment of the structure of the state at home and abroad, summarizes the state of the current domestic and international assessment theory and its methods. Basic theory of chaotic time series, and explore the chaotic system characteristic parameters defined its calculation method, first proposed bridge structure has the characteristics of non-linear dynamical systems, the application of the theory of chaotic time series study bridge structure status. (2) through the analysis of a large number of bridge health monitoring information, asked the Singularity Detection of bridge health monitoring of time series data, and time series denoising methods. Eliminate the promiscuous monitoring signal interference and noise, so that it can truly restore the actual vibration signals, bridge health monitoring for the later time series analysis to provide reliable data. (3) theory and its analysis method based on chaotic time series, respectively, of Bridge Masangxi and ASCE Benchmark structure health monitoring information for analysis and research, in the analysis of the nonlinear characteristics of the bridge structure system with the characteristic parameters of the chaotic time series and its algorithm with Matlab numerical analysis based on acquiring system indicators. Experimental results show that: the largest Lyapunov exponent of ASCE, Benchmark House, structure and Chongqing Masangxi bridge structure system are greater than 0 and the largest Lyapunov exponent sample correlation dimension are non-integer greater than 2, according to the related theory shows that the system is chaotic phenomena exists; The quantity and time delays have a certain sensitivity and the λmax of, D2, with structural change and evolution, with the ability to identification structure state. Verified by numerical simulations and real-bridge applications, based on the characteristics of the chaotic system in the long-term monitoring of the existing bridge condition assessment the feasibility and effectiveness of the technology. This paper presents a method of operating condition of a large bridge condition assessment has certain reference.

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