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针对时变环境温度对实际桥梁结构的动力特性影响问题,进行了试验研究。首先,对某一吊杆拱桥模型进行了长期动力测试,通过模态参数识别,得到了该结构在不同温度下的前6阶频率、阻尼比和振型;其次,采用测试模态参数,利用子结构方法对该拱桥模型进行了有限元模型修正;再次,将结构的测试模态参数与修正后有限元模型的动力特性进行了比较分析;最后,通过回归分析,建立了环境温度与结构频率的关系模型,并利用该模型建立了测试结构在完好状态下的置信区间,从而利用该置信区间对测试模型结构的性能进行了诊断。研究发现:测试结构的频率随环境温度的升高呈下降趋势,而测试结构的阻尼比、振型对环境温度的变化并不敏感。
Aiming at the influence of time-varying ambient temperature on the dynamic characteristics of the actual bridge structure, a pilot study was carried out. Firstly, a long-term dynamic test was conducted on a boom arch bridge model. The first 6 orders of frequency, damping ratio and mode shape of the structure at different temperatures were obtained by modal parameter identification. Secondly, by using the test modal parameters, Sub-structure method was used to modify the finite element model of the arch bridge model. Thirdly, the dynamic characteristics of the tested modal parameters and the modified finite element model were compared and analyzed. Finally, by regression analysis, the relationship between ambient temperature and structure frequency The model is used to establish the confidence interval of the test structure in the intact state, so that the performance of the test model structure can be diagnosed by using the confidence interval. The results show that the frequency of test structure decreases with the increase of ambient temperature, while the damping ratio and mode shape of test structure are not sensitive to the change of ambient temperature.