Konzepte für die Bewertung von Brücken mit Spannungsrisskorrosionsgefahr

Schacht, Gregor; Käding, Max; Bolle, Guido; Marx, Steffen

doi:10.1002/best.201800087

Cited by 15 publications

(6 citation statements)

References 11 publications

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“…Although AE has repeatedly proven its suitability for detecting damage, the method is not yet commonly used in civil engineering outside the laborytory. In Germany, several bridges are monitored permanently with AE to detect damage like prestressing wire breaks or breaks in welding seams [1]. AE to detect wire breaks is recommended for prestressed buildings with risk of stress crack corrosion, other crack risks or for buildings which cannot be inspected according the required standards.…”

mentioning

confidence: 99%

Acoustic Emission in der Bauwerksüberwachung zur Feststellung von Spannstahlbrüchen

Sodeikat¹,

Groschup²,

Knab³

et al. 2019

Beton und Stahlbetonbau

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Die Schallemissionsmessung Acoustic Emission (AE) ist ein Messverfahren, welches in der Materialforschung, in der Materialprüfung im Labor und in der Dauerüberwachung im Anlagen‐ und Maschinenbau seit Jahrzehnten erfolgreich eingesetzt wird. Im Bauwesen stellt die AE noch kein etabliertes bzw. übliches Messverfahren dar, auch wenn die Tauglichkeit des Verfahrens zur Detektion von Schadensereignissen in der Praxis mehrfach bewiesen wurde. In Deutschland unterliegen derzeit mehrere Brücken einer Dauerüberwachung, bei der AE einen wichtigen Baustein darstellt, um Veränderungen des Tragverhaltens bzw. eine zunehmende Schädigung in Form von Spannstahlbrüchen oder Schweißnahtrissen zu erfassen, z. B. [1]. AE zur Detektion von Spannstahlbrüchen empfiehlt sich bei Bauwerken mit spannungsrisskorrosionsempfindlichen Spannstählen, anderweitig korrosions‐ bzw. rissgefährdeten Spannstählen oder auch bei Neubauten, bei denen die Anforderungen an Bauwerksprüfungen nach DIN 1076 oder RIL 804 nicht eingehalten werden können. In diesem Beitrag werden Beispiele für AE‐Monitoring zur Spannstahlbruchdetektion an verschiedenen Bauwerken vorgestellt. Ferner werden Ergebnisse zu gezielt herbeigeführten Spannstahlbrüchen und Schlagbeanspruchung an Bauwerken und an Testkörpern dargestellt, ergänzt um zwei numerische Simulationen der Wellenausbreitung.

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mentioning

confidence: 99%

Acoustic Emission in der Bauwerksüberwachung zur Feststellung von Spannstahlbrüchen

Sodeikat¹,

Groschup²,

Knab³

et al. 2019

Beton und Stahlbetonbau

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“…To compensate for potential structural deficiencies resulting from the gradual failure of prestressing steel, targeted monitoring is essential. Acoustic emission monitoring (AEM) has proven to be an effective method for detecting wire breaks and is increasingly being applied in the construction industry [4][5][6][7]. Furthermore, this method can be applied not only to prestressed concrete bridges, but also to monitor damage to cables in suspension and cable-stayed bridges [8][9][10][11].…”

Section: Introductionmentioning

confidence: 99%

Acoustic Emission Monitoring in Prestressed Concrete: A Comparative Study of Signal Attenuation from Wire Breaks and Rebound Hammer Impulses

Käding,

Marx

2024

Applied Sciences

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Acoustic emission monitoring (AEM) has emerged as an effective technique for detecting wire breaks resulting from, e.g., stress corrosion cracking, and its application on prestressed concrete bridges is increasing. The success of this monitoring measure depends crucially on a carefully designed sensor layout. For this, the attenuation of elastic waves within the structure’s material is ideally determined in situ through object-related measurements (ORMs) with a reproducible signal source, typically a rebound hammer. This assumes that the attenuation coefficients derived from rebound hammer tests are comparable to those from wire breaks, thus allowing their results to be directly applied to wire break detection without further adjustments. This study challenges this assumption by analysing attenuation behaviour through an extensive dataset. Employing time-domain and frequency analysis, the research generates attenuation profiles from laboratory experiments and in situ measurements across various girders and bridge structures, extracting the slope and residual standard deviation (RSD). While generally validating this approach, the findings highlight differences in attenuation behaviour from among wire break signals and rebound hammer impulses, whereby the latter potentially underestimates the relevant attenuation of wire breaks by approximately 20%. Consequently, a transfer factor is proposed to adjust ORM results obtained with the rebound hammer for wire break scenarios. It consists of a scaling factor of 1.2 to modify the average attenuation coefficient and a constant term of ±1.0 dB/m to cover a 95% confidence interval, and thus, account for sample scattering. Moreover, the anisotropic attenuation behaviour across different structures was studied, showing that transverse attenuation consistently exceeds the longitudinal, significantly influenced by structural features such as voids. In prefabricated concrete bridges with in situ-cast concrete slabs, transverse signal transmission remains unhindered across multiple elements. Finally, the results provide a valuable reference for the design of sensor layouts in bridge monitoring, particularly benefiting scenarios where direct in situ experiences are lacking.

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“…Therefore, with the rise and broad availability of cost-effective compute resources and storage media, the interest in automated structural health monitoring (SHM) solutions gained increasing interest. With regard to prestressed concrete structures, one specific problem is the breakage of individual wires in steel tendons due, for example, stress corrosion cracking [2][3][4]. Since this kind of damage is visually not observable, researchers investigated non-visual techniques originating from the field of non-destructive testing.…”

Section: Introductionmentioning

confidence: 99%

Matched Filter for Acoustic Emission Monitoring in Noisy Environments: Application to Wire Break Detection

Lange,

Xu,

Kaeding

et al. 2024

Acoustics

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Regular inspections of important civil infrastructures are mandatory to ensure structural safety and reliability. Until today, these inspections are primarily conducted manually, which has several deficiencies. In context of prestressed concrete structures, steel tendons can be susceptible to stress corrosion cracking, which may result in breakage of individual wires that is visually not observable. Recent research therefore suggests Acoustic Emission Monitoring for wire break detection in prestressed concrete structures. However, in noisy environments, such as wind turbines, conventional acoustic emission detection based on user-defined amplitude thresholds may not be suitable. Thus, we propose the use of matched filters for acoustic emission detection in noisy environments and apply the proposed method to the task of wire break detection in post-tensioned wind turbine towers. Based on manually conducted wire breaks and rebound hammer tests on a large-scale test frame, we employ a brute-force search for the most suitable query signal of a wire break event and a rebound hammer impact, respectively. Then, we evaluate the signal detection performance on more than 500 other wire break signals and approximately one week of continuous acoustic emission recordings in an operating wind turbine. For a signal-to-noise ratio of 0 dB, the matched filter approach shows an improvement in AUC by up to 0.78 for both, the wire break and the rebound hammer query signal, compared to state-of-the-art amplitude-based detection. Even for the unscaled wire break measurements originally recorded at the 12 m large laboratory test frame, the improvement in AUC still lies between 0.01 and 0.25 depending on the wind turbine noise recordings considered for evaluation. Matched filters may therefore be a promising alternative to amplitude-based detection algorithms and deserve particular consideration with regard to Acoustic Emission Monitoring, especially in noisy environments or when sparse senor networks are required.

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Konzepte für die Bewertung von Brücken mit Spannungsrisskorrosionsgefahr

Cited by 15 publications

References 11 publications

Acoustic Emission in der Bauwerksüberwachung zur Feststellung von Spannstahlbrüchen

Acoustic Emission in der Bauwerksüberwachung zur Feststellung von Spannstahlbrüchen

Acoustic Emission Monitoring in Prestressed Concrete: A Comparative Study of Signal Attenuation from Wire Breaks and Rebound Hammer Impulses

Matched Filter for Acoustic Emission Monitoring in Noisy Environments: Application to Wire Break Detection

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