Society depends on critical infrastructure to support everyday activities. Even as critical components of civil infrastructure approach and exceed their design lives, demand on these structures continues to increase. In light of the need for managing aging infrastructure, several opportunities exist for research that can aid infrastructure managers in significant the challenge of detecting, classifying, and mitigating structural impairments. This dissertation presents a novel framework for impairment detection through the capture and utilization of deformation influence lines for flexural rigidity estimation on Euler-Bernoulli beams. In this research study, mechanical theory, a computer-vision algorithm, and multiple numerical methods are integrated to demonstrate the feasibility of the FRE method. The theoretical relationship between the second derivative of the deformation influence line and the flexural rigidity of a beam is developed. This formulation allows for both the location and quantification of damage directly from either beam deflections or rotations caused by moving loads. To overcome the challenges arising from noisy measurements that occur in practical applications, three numerical methods are proposed and compared: Moving Window (MW), Least-mean Square Error (LSQ), and Tikhonov Regularization (TR). In the analytical studies, the performance of the proposed methods in different combinations of noise level in the measurement and number of measurements is studied. Additionally, a camera-based deformation measurement method is presented and evaluated to measure deflection or rotation influence lines in a non-contact manner. Ultimately, small and medium scale experimental tests were conducted and confirmed the applicability of the FRE method to beam structures. Results show that, even in presence of measurement noise (1%), the FRE framework predicts flexural rigidity with 95% accuracy.
Civil And Environmental Engineering
Brett A. Story
Number of Pages
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This work is licensed under a Creative Commons Attribution-Noncommercial 4.0 License
Hajizeinalibiouki, Yasha, "Flexural Rigidity Estimation Using Noisy Static Influence Lines" (2018). Civil and Environmental Engineering Theses and Dissertations. 1.