The aging engineering infrastructure is a growing problem in many countries and thus a challenge to make optimal decisions for their further safe operation. Therefore, effective diagnostic solutions are being sought to enable a reliable assessment of their technical condition. The article presents the results of static and high-frequency strain measurements of a 57-year-old posttensioned crane girder, dismantled from one of the production halls. In particular, the anchorage zone and transmission length of the tendon related to the quality of cement injection around the prestressing tendon were analyzed. For this purpose, a distributed fiber optic sensing (DFOS) technique was applied, which allows performing strain measurements with a spatial resolution starting from 2.6 mm (almost 385 measuring points per 1 m of the optical fiber). The application of such an approach allowed for detailed analysis in both longitudinal and transverse directions, including crack detection and estimation of their widths. The article describes in detail the sensing fibers and applied methodology, as well as the results of both static and high-frequency tests performed under laboratory conditions during cutting one of the tendon's anchorage off.

中文翻译：

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使用静态和高频方法对 57 岁后张法预制梁锚固区应变分析的 DFOS 测量

在许多国家，老化的工程基础设施是一个日益严重的问题，因此为进一步安全运营做出最佳决策是一项挑战。因此，正在寻求有效的诊断解决方案，以实现对其技术状况的可靠评估。本文介绍了从其中一个生产车间拆除的 57 年历史的后张式起重机梁的静态和高频应变测量结果。特别是分析了与预应力钢筋束周围注水泥质量有关的钢筋束锚固区和传输长度。为此，应用了分布式光纤传感 (DFOS) 技术，该技术允许以 2.6 mm 的空间分辨率进行应变测量（每 1 m 光纤几乎有 385 个测量点）。这种方法的应用允许在纵向和横向上进行详细分析，包括裂纹检测和宽度估计。这篇文章详细描述了传感纤维和应用方法，以及在实验室条件下在切断肌腱的一个锚固点期间进行的静态和高频测试的结果。