Development of Diagnostic Procedure for Concrete Structures

诊断程序进行调查，以发展的评价和检查技术。待研究和实际应用的技术与裂缝、分层、表面损伤、钢筋腐蚀和结构完整性有关。为此，新开发和改进了声发射（AE）法、超声检测（UT）法、红外热成像法、雷达法和半电池电位法。本文还研究了结构完整性的评估，包括基于老化桥梁数据库的专家系统，取得了如下成果：（1）改进了超声波检测方法，发展了基于光谱信息的裂纹深度和表面劣化识别新技术。(2)研究了声发射在混凝土芯样测试中的应用。在对岩样声发射行为进行速率过程分析的基础上，结合损伤力学理论，提出了岩样损伤的定量评价方法。(3)研究了声发射波形的矩张量分析，从而开发了一个实用的程序来识别裂纹位置，裂纹类型和裂纹取向。(4)提出了钢筋锈蚀的两步检测方法。第一步，采用雷达技术确定加固位置。然后，在第二，钢筋上的腐蚀电位估计从表面上的半电池电位，通过电荷模拟方法解析。(5)研究了红外热像技术在混凝土表面温度分布估计中的应用。针对钢筋锈蚀问题，提出了一种基于边界元法（BEM）的钢筋锈蚀反问题求解方法。

Diagnostic procedure is investigated in order to develop the evaluation and inspection techniques. The techniques to be studied and to be practically applied are associated with crack, delamination, surface damage, corrosion of reinforcement, and structural integrity. For this purpose, acoustic emission (AE) method, ultrasonic testing (UT), infrared thermography, radar, and half-cell potential are newly developed and improved. The evaluation of structural integrity is also studied, including an expert system based on the data base of aging bridges.Results obtained are summarized, as follow :(1) The UT measurement was improved and a new technique based on the spectral information was developed to identify crack depths and surface deterioration.(2) AE application to core tests of concrete is investigated. On the dasis of the rate process analysis of AE generating behaviors in the core sample and the damage mechanics, a quantitative evaluation of damage in the core sample is developed.(3) A moment tensor analysis of AE waveforms was investigated and thus a practical procedure is developed to identify crack location, crack type, and crack orientation.(4) To estimate corrosion of reinforcement, two step inspection is proposed. At the first step, location of reinforcement is determined by employing the radar technique. Then, at the second, corrosion potentials on the reinforcement are estimated from half-cell potentials on the surface, by the charge simulation method analytically.(5) The infrared thermography was studied to estimate temperature distribution on concrete surface. Concerning the corrosion of reinforcement, an inverse solution based on the boundary element method (BEM) is newly developed.