封闭式连通管挠度测量系统动态特性研究

挠度的长期、自动、准确、快速测量一直是大跨度桥梁监测的重点和难点.在简要对比现有挠度监测方法的基础上,介绍了近年来兴起的封闭式连通管挠度测量系统,分析了其动态挠度测量的实现原理和量值传递过程,通过振动台试验测定了系统的动态特性.理论分析和试验结果表明,压力传感器的存在改变了管道的终端阻抗,显著影响了管道压力传递的动态特性;同时压力传感器较低的通频带可能会带来不可忽视的测量失真.针对这两个影响因素,讨论了提升系统动态特性的可行方法,并对系统的研究和改进方向提出了建议.

Dynamic Characteristic of Closed-End Connecting Pipe Deflection Monitoring System

The long term, automatic, accurate and dynamic measurement of deflection has always been an important but difficult issue in large span bridge monitoring systems. In this paper, on the basis of a brief comparison of the existing deflection monitoring methods, focuses are made on the most promising closed- end connecting pipe deflection monitoring system, which has the potential of satisfying all the requirements of the large span bridge deflection measurement. So, firstly the principle of the method and value transfer process are discussed, and then the dynamic characteristics of the system components are tested on a vibration table. Theoretical analysis and test results show that, the existence of pressure transmitter changes the terminal impedance of the connecting pipe, which tremendously influences the dynamic characteristic of the pressure transmission; meanwhile, the low pass band of the pressure transmitter may in- duce ineligible error during the measurement process. Against these two problems, feasible methods to improve the dynamic characteristic of the system are discussed, and suggestions are made on the technical improvement directions as well as the development trends at last.