NDT Data-Supported Structural Reassessments based on Regression Relations in Measuring Data Analysis

• Published in: E-journal of Nondestructive Testing 2024-07, Vol.29 (7)
• Main Authors: Bahrami Eskandari, Ardalan, Küttenbaum, Stefan
• Format: Article
• Language: English
• ISSN: 1435-4934; 1435-4934
• DOI: 10.58286/29714

Non-destructive Testing (NDT) yields valuable data on actual structural elements, supporting the assessment of existing infrastructures while minimizing additional structural damage caused by inspections. Simultaneously, the uncertainty in measurement, which quantifies the quality of measurement results, plays a crucial role in decisions aimed at, e.g., optimizing maintenance strategies, rehabilitation works and Structural Health Monitoring (SHM) implementations. The Guide to the Expression of Uncertainty in Measurement (GUM) framework has been already applied to non-destructive concrete testing. This necessitates an obligatory process in which extensive measurements with strictly limited scopes need to be conducted by expert personnel. This study aims to simplify and optimize existing NDT data analysis procedures by employing regression analysis, enabling the detection of structural features. The regression analysis yields a modifier for determining the correct depth of an object within the structural element as well as an intercept in the linear input-output formulation, with time of flight serving as the variable and wave velocity as its slope. The method is validated through laboratory experiments, including the use of an ultrasonic measurement system. The introduced method provides unbiased and accurately measured results, while the measurement data can be uncorrelated. Major advantages are faster computations, a wider scope and a notable reduction in the amount of needed information about the measuring process. Furthermore, the study illustrates how the regression relation approach, in combination with ultrasonic data describing the inner structure of a concrete element, can effectively support the reassessment of bridges in operation. To achieve this, the measurable positions of the resisting longitudinal tendons of a bridge structure are varied to investigate the displacement change under dynamic service loads. The findings reveal that the application of the proposed NDT analysis method, with its increased practicability, can enhance the efficiency of NDT data-supported structural reassessments in different scenarios.