The Communicating Pipe Opto-Electronic Deflection Measurement System In Long Span Bridge

As one of the leading parameters in reflecting the health of a bridge's construction, the deflection of a bridge has been always studying by the bridge professionals, and hence many measurements are put forward and working practicably. Among of those measurements on the deflection, especially upon a long span bridge, a measuring instrument of communication-pipes enjoys a good comment as much measuring points, weak-influenced by the surroundings. But it still meets a weakness of manual measuring, lower accuracy, slower speed and so on. Therefore, photoelectric technology was introduced into the communication-pipes instrument in order to improve its performance. Finally, an automatic measuring system of the bridge's deflection had been developed, which meet the needs of long-term on-lined, auto-measuring upon the deflection measuring of the long-span bridge. It has an important theoretical meaning and practical value.This thesis is firstly to set up a simple mechanical model and to deduce the formula of bridge's deflection, and then to analysis the distribution of the bridge's deflection in order to provide a reference for identifying the distribution of the deflecting points and the measuring range. Secondly, a special sensor was designed and made to measure the deflection of the long-span bridge. TMS320C32 (an DSP IC of TI) was adopted as the processor of this measuring system, which completes the data's collecting and processing. Standard RS-485 interface was utilized to accomplish the signal's remote conveying and communication, and watchdog technology was also introduced to accomplish the supervisory control against the circuit and to ensure the system's stable running. After solving a number of hardware and software problems, a bridge deflection measurement system was finally built up. Lots of experiments were carried to testify the performance of the system. To our satisfaction, testing results demonstrated that this bridge deflection measuring system is convincing, and accurate. Other advantages, such as large measuring range, automatic and remote working capability and so on, were also proved. Which makes it clear that the system can meet the demands of measuring upon the long-span bridge's deflection, and the system has the practical value.