公路现役桥梁结构的动力特性参数测试技术研究

发布时间：2018-04-19 23:32

本文选题：环境激励 + 动力特性参数　；参考：《大连海事大学》2014年硕士论文

【摘要】：桥梁动力特性参数的获取,对于分析桥梁结构的抗风抗震性能、校核桥梁结构的固有频率和振型、快速准确评价桥梁健康状况起到数据支持作用,同时有助于早期发现桥梁动态病害、降低维修养护费用、加强桥梁的管理,对于确保桥梁结构使用性能、保证人民生命财产安全等方面具有重要现实意义。传统结构动力特性参数的识别方法,在识别过程中需要同时得到动力测试响应的时程曲线和激振力数据,从而利用模态分析办法,计算获得各个测试点处激振力之间的频率响应函数,从而根据频域数据计算得到桥梁结构的动力特性参数,或者根据各个激振力之间的脉冲响应函数,根据数域数据计算得到结构的动力特性参数。在实际工程中,大跨度桥梁结构往往采用环境激励法,在动力特性测试中无法采集到激振力的信号,因此采用传统动力特性参数识别办法无法直接在环境激励条件下的动力响应里获得桥梁结构的动力特性参数,需要对桥梁结构动力特性参数的选取办法进行优化。本文根据随机减量技术,在环境激励条件下的随机响应中获得结构的自由衰减响应,在此基础上,利用小波变换理论形成在自由衰减响应条件下,计算桥梁结构振型和频率的理论方案。在频率识别结果的基础上,推导得到了基于自由衰减信号的桥梁结构各级阻尼比的理论计算方法。建立有限元分析模型,结合工程实际优化设计动力测点,并对该桥进行环境激励,得到该桥梁结构各测点的动力响应数据,基于随机减量法获得动力测点的自由衰减响应数据,进而计算出该桥梁结构的振型、频率以及阻尼比。最后,本文研究了工程中采用的跑车试验激励条件下桥梁结构冲击系数理论计算,并以某连续箱梁桥为例,进行了跑车试验,通过计算得出该桥的冲击系数。
[Abstract]:The acquisition of bridge dynamic characteristic parameters plays a data support role in analyzing the wind-resistant seismic performance of bridge structure, checking the natural frequency and vibration pattern of bridge structure, and evaluating the bridge health status quickly and accurately. At the same time, it can help to find the bridge dynamic diseases early, reduce the maintenance cost, strengthen the bridge management, ensure the bridge structure performance, ensure the safety of people's life and property and so on. The traditional identification method of structural dynamic characteristic parameters needs to obtain the time history curve and excitation force data of dynamic test response at the same time in the process of identification, so that the modal analysis method is used. The frequency response function of the exciting force at each test point is obtained, and the dynamic characteristic parameters of the bridge structure are calculated according to the frequency domain data, or the impulse response function between the various exciting forces is obtained. The dynamic characteristic parameters of the structure are calculated according to the numerical data. In the actual engineering, the environmental excitation method is often used in the long-span bridge structure, and the signal of the exciting force can not be collected in the dynamic characteristic test. Therefore, the traditional dynamic characteristic parameter identification method can not obtain the dynamic characteristic parameters of the bridge structure directly in the dynamic response under the environmental excitation condition, so it is necessary to optimize the method of selecting the dynamic characteristic parameters of the bridge structure. In this paper, according to the random decrement technique, the free decay response of the structure is obtained in the random response under the environment excitation condition. On this basis, the wavelet transform theory is used to form the free attenuation response condition. A theoretical scheme for calculating the modes and frequencies of bridge structures. Based on the results of frequency identification, the theoretical calculation method of damping ratio of bridge structure based on free attenuation signal is derived. The finite element analysis model is established, the dynamic measuring point is optimized and the dynamic response data of each measuring point of the bridge structure are obtained by the environmental excitation of the bridge, and the free attenuation response data of the dynamic measuring point are obtained based on the random decrement method. Then the vibration mode, frequency and damping ratio of the bridge are calculated. Finally, this paper studies the theoretical calculation of the impact coefficient of bridge structure under the exciting condition of sports car test, and takes a continuous box girder bridge as an example, carries out the sports car test, and obtains the impact coefficient of the bridge by calculation.
【学位授予单位】：大连海事大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U441

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