Crack monitoring on concrete structures with distributed fiber optic sensors—Toward automated data evaluation and assessment

Abstract

The ability to measure strains quasi‐continuously with high spatial resolution makes distributed fiber optic sensing a promising technology for structural health monitoring as it allows to locate and measure damages in concrete structures, such as cracks. Depending on whether the distributed fiber optic sensor (DFOS) is embedded into the concrete matrix or bonded to the reinforcement, different approaches for crack width calculation exist. The high spatial resolution of DFOS quickly leads to a large amount of data, especially with time continuous monitoring. Scalable, automated analysis approaches are required to handle such big data and to derive a gain in knowledge from the measurements. Thus, in a first step, the Python framework fosanalysis is presented and made available to other researchers or monitoring specialists as free software. The most important input parameters for crack width calculation are discussed for concrete strain and steel strain DFOS. Accurate crack monitoring for a 4 m long reinforced concrete beam is demonstrated by using fosanalysis. The calculated crack widths are in good agreement with digital image correlation measurements.

Konzept eines Digitalen Zwillings für Brückenbauwerke in der Betriebsphase

“…In IDA-KI sollen dafür auch Methoden des maschinellen Lernens zum Einsatz kommen [16]. Hilfreich können auch Methoden der Datenverbesserung sein [17]. 4.…”

Towards an Automated Crack Monitoring using Distributed Fiber Optic Sensors

“…The most import parameters are discussed at the example of two selected DFOS. The algorithms are implemented as a Python program [16].…”

“…In several studies [10] [11] [16], the location of the minimum strain in-between crack locations is proposed. With this "min"-approach, the transfer length is calculated as:…”

“…The ORM sensor was glued into a groove in the middle tensile reinforcement bar by cyanoacrylate adhesive and protected with a thin silicone layer against mechanical and chemical attack. An equivalently applied polyimide coated DFOS, is compared to the same ES [16]. The ORM coating showed higher resistance against the alkaline environment in comparison to the polyimide coating.…”

openLAB – Eine Forschungsbrücke zur Entwicklung eines digitalen Brückenzwillings

“…So ist es beispielsweise möglich, Risse anhand lokaler Dehnungsspitzen im Messsignal sowohl ortsgenau zu detektieren als auch deren Rissbreiten präzise zu bestimmen[44][45][46][47][48]. Ein Vorgehen zur automatisierten Rissüberwachung mittels DFOS[49] besteht aus den Schritten (i) Datenakquise, (ii) Vorverarbeitung, (iii) Rissdetektion, (iv) Festlegung der Integrationsbereiche, (v) Kompensation von Störeinflüssen und (vi) Rissbreitenberechnung durch numerische Integration des Dehnungssignal innerhalb der Einflusslänge eines Risses. Dieses Vorgehen wurde in der Programmbibliothek fosanalysis umgesetzt, die als freie Software (Open Source) zur Verfügung steht und im Verlauf des Projekts weiterentwickelt wird [49, 50].…”