Assessment of the current condition of structures using nondestructive modeling and parameter estimation techniques

摘要

Abstract: Structures, however well designed, may experience excessive cycling or variations of design loads. These could result in higher stress levels causing accelerated deterioration or `wear' in these structures. Eventually, these types of deterioration may cause defects or damage in the structure. In case of a bridge, if not detected on time, these types of deterioration may result in catastrophic failures. This paper proposes to develop techniques that will determine the prevailing condition of a structure in a way that will indicate its structural integrity in a quantifiable manner. These techniques will assist in evaluating the existing condition of and will help to design a structure better as well. The performance of a structure can also be predicted by these methods. These techniques will include modeling of a structure, nondestructive testing, and utilization of statistical estimation methods. Most importantly, the methods will provide a `tool' for personnel in charge of the inspection of such structures, bridge inspectors for example, to perform inspections in a more objective and scientific way. Presently, these inspections are generally carried out visually and in a subjective manner. By taking a deflection and/or strain measurement at a point, a bridge inspector, with the help of a set of curves, will be able to quantify the existing condition of that structure compared to its original or new state. Equipped with this tool and periodic checking, an inspector will then be able to assess deterioration of a structure over time. Historical data will then be available for the inspection team to evaluate the performance of the structure. If the data show more than expected `wear,' appropriate action can be taken to avoid occurrences of damages or defects and in extreme cases total replacements of a structure. These actions will not only save resources such as money, material, and time, it may save lives as well. !11