Development of the high accurate structural identification system for bridge health monitoring

本研究以开发桥梁健康监测系统为目的，构建了高精度的结构识别理论，并进行了验证试验。本研究的主要结论如下.高精度结构识别的构造理论：提出了一种高精度估计结构固有频率的结构识别算法。在此基础上，提出了对结构固有频率进行详细提取的物理提取方法。通过对拱桥环境振动的一系列仿真，验证了该方法在频率自动估计中的有效性.高精度结构识别系统的研制：研制了一套便携式高精度结构识别测量系统。该系统通过在桥面上安装传感器，实现了对结构自振频率的自动估计.通过模型振动台试验验证该系统：一个建筑模型，通过在每层安装支撑产生结构劣化，用于振动台试验。该测试验证了该系统检测结构退化的潜力。频率差被设计得很小，因为当它变坏时，频率变化不大.在某既有桥梁中的应用：通过一系列的研究和试验，完成了高精度的结构损伤识别系统。最后，在一座既有桥梁上进行了现场测试，验证了该系统对桥梁振动特性估计的有效性.新目标：继2001-2002年科研资助（B）后，该系统将在2003-2005年科研资助（B）下陆续升级为桥梁结构维修系统长期监测系统。

On the purpose of developing health monitoring system for bridges, in this study, the high accurate structural identification theory was structured and verification tests were conducted. Summery of this study are bellows.1. Structuring theory of the high accurate structural identification : A structural identification algorithm, which estimates the structure's natural frequency with high accuracy, was developed. Furthermore, the physical extraction method, which extracts structure's natural frequency in detail, was proposed. The method was verified to be useful for estimating frequency automatically, through series of simulation with ambient vibration of arch bridge.2. Development of the high accurate structural identification system : A portable measurement system with the high accurate structural identification method was developed. This system enables to estimate the structure's natural frequency automatically by installing sensor to the bridge surface.3. Verification of the system by model-shaking table test : A building model, which produces structural deterioration by installing braces in each story, was used for shaking table test. This test verified the system's potential to detect structural deterioration. The difference of the frequency was designed extremely small because the change of frequency is not wide when it comes to be deteriorated.4. Application to an existing bridge : As a result of the series of the study and test, the high accurate structural identification system, which detects structure's damage, was completed. Furthermore, a field test at an existing bridge was conducted and the system was verified to be useful for estimating bridge vibration characteristics.5. New target : After the 2001-2002 Grant-in-Aid for Scientific Research (B), this system will be consecutively upgraded to long-term-monitoring system for maintenance system of bridge structures under the 2003-2005 Grant-in-Aid for Scientific Research (B).