【摘要】 桥梁结构的动力特性能够很好地表现桥梁的健康状况和损伤状态,分别通过环境随机激振技术和定点跳车激振方法对一座刚架桥的动力特性进行了测试,给出了利用随机振动理论和响应传递函数识别结构的频率、振型和阻尼比的方法,并对两种测试方法进行了比较。通过ANSYS建立空间有限元模型,对桥梁结构的无载和有载动力特性进行了仿真分析。实测与理论分析表明:按本方案测试获得的试验结果较为理想,环境激励测试能获得更多阶的振型和自振频率;而跳车激振方法只能很好地激发结构的基本弯曲振动模态。通过试验研究结果验证了有限元动力分析模型的正确性,可为同类桥梁的测试和分析提供参考。更多还原

【Abstract】 The dynamic characteristic is an important index to evaluate the health and damage state of highway bridges. The key procedures and scheme of ambient random excitation technique and truck jumping excitation method were discussed and applied to determine the dynamic characteristics of a preselected bridge. The frequencies, mode shapes and damping ratios of the testing bridge are identified using random vibration theory and response transfer function. Numeric analyses of unloaded and loaded bridge are carried out by ANSYS program and compared to the experimental results. It indicates that the ambient random excitation technique can excite more frequencies and modes, and the truck jumping excitation method can only excite the fundamental bending modes well. The FE analysis modal is validated by the experimental results as well. It is believed that the present work can provide a reference for the test and analysis research of rigid-frame bridges.更多还原