期刊名称：ISPRS Annals of the Photogrammetry, Remote Sensing and Spatial Information Sciences
印刷版ISSN：2194-9042
电子版ISSN：2194-9050
出版年度：2004
卷号：XXXV Part B5
页码：678-683
出版社：Copernicus Publications
摘要：Controlling and monitoring of crack origin and evolution of concrete elements is an important task in research of building materials. The efficiency of the reinforcement to the bearing capacity depends among other on the limited crack evolution. Regarding the research of crack evolution at the surface of the element, photogrammetry is approved, because it allows an expanded investigation of larger objects with high precision. With the presented experiments different structural elements of prestressed, reinforced and textile concrete are investigated. These are tension, shear beams and plate elements. For the photogrammetric measurements the surface is prepared by a grid of targets. Up to three digital cameras (Kodak DCS Pro 14n) are used as a multi exposure assembly or as a static one-camera-system. Cracks are causing local changes to the displacements between the targets. Repeating the measurement in time intervals the crack evolution can be observed. The digital images are evaluated by the photogrammetric software PHIDIAS; it yields a precision of the target coordinates up to 3μ m. For analysing deformation, a software is developed to detect crack structures. Hereby the measurement data and the parameters of material are probabilistically regarded in the existence probability of a crack. The values are improved by intensification methods and then single cracks are automatically traced. Detail information like crack width and crack edge displacement are also calculated. In addition a Finite- Element- Module is developed, which simulates the test. Thus the results of photogrammetric measurements can be compared with the numeric tension calculation and iteratively improved. The described measurement and analysis system is developed at the Geodetic Institute of RWTH Aachen, University (Germany). The tests are realised at the Institute of Structural Concrete, the Institute of Building Material Research and Institute of Textile Technique, all RWTH Aachen. The work is part of the research activities referring to the "Sonderforschungsbereich 532 - Textilbeton" (Collaborative Research Centre financed by the DFG (German research association) for textile concrete)
关键词：Change Detection; Tracing; High resolution; Expert System; Automation; Engineering
