Modal identification of a reduced-scale masonry arch bridge with experimental measurements and finite element method

Abstract

This study aims to investigate modal parameters such as mode shapes, natural fre-quencies and damping ratios of a reduced scale one-span historical masonry arch bridge constructed in laboratory conditions by performing numerical and experi-mental analysis. Sarp Dere historical masonry bridge, in Ordu, Ulubey, has 15.5 m in length and 4.75 m in width was chosen as a prototype model. The reduced-scale bridge model and structural details were carried out in the scale of 1:12.5. Opera-tional Modal Analysis (OMA) technique was used for experimental study. The exper-imental modal parameters of the bridge model were figured out by using Enhanced Frequency Domain Decomposition (EFDD). ANSYS software was used to create 3D finite element (FE) model and to expose the analytical modal parameters of the re-duced-scaled bridge model. Moreover, FE model of the reduced-scale bridge model was calibrated based on the experimental results by using the Response Surface based FE model calibration technique to obtain more accurate results. The analysis results of experimental, initial and calibrated FE model were compared. It is noted that there are significant differences between the modal parameters obtained from experimental and initial FE model. Model calibration techniques are beneficial to get a more reasonable FE model.