Abstract:

Experimental investigations of large and complex structural systems can be carried out by reduced- scale models in terms of convenience, time-saving and economical. This can be applied to different fields of study such as vibration, impact and explosion problems in structural engineering and allows reliable analysis to understand the static and dynamic behavior of real structures called a prototype. This study aims that a 1/3 reduced-scale model is created in the laboratory environment considering similitude requirements by selecting a single span historical masonry arch bridge as a prototype structure. For this purpose, the Operational Modal Analysis (OMA) Technique is utilized for experimental study to determine modal parameters of the prototype and model bridges. Sensitive accelerometers were located on critical points on the structures and signals originated by accelerometers were collected to quantify the vibratory response of the model and prototype bridges. The Enhanced Frequency Domain Decomposition (EFDD) is employed to identify the natural frequencies, mode shapes, and damping ratios experimentally. The similarity of the dynamic behavior of the reduced-scale bridge model and prototype are investigated. The analysis of the similarity in the dynamic behavior of the prototype and model bridge consists of two steps. The first step involves comparing the natural frequencies corresponding to the translational, bending and torsional modes of the prototype and model bridges. This comparison was made in accordance with the similitude requirements. The second step includes the comparison of the corresponding mode shapes obtained from the prototype and the model bridge by utilizing the modal assurance criterion (MAC). As a result of the study, it is concluded that the dynamic behavior of the reduced-scale bridge model is similar to the dynamic behavior of the prototype bridge.

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