Dynamic Analysis and Finite Element Model Updating of Long-Span Stone Arch Bridge
[Purposes]This paper aims to obtain the dynamic performance of the Changhong Bridge in Kaiyuan City,Yunnan province and to ensure a more accurate finite element analysis model.[Methods]The dynamic characteristics of the Changhong Bridge are tested by the method of environmental excita-tion,and the measured modal parameters are analyzed;according to the results of the measured modal parameters,the parameters such as elastic modulus and Poisson's ratio in the finite element model are modified;based on the theoretical and measured modal analysis results,a more accurate finite element analysis model of Changhong Bridge is obtained.[Findings]The results show that the vibration deforma-tion of stone arch bridge is large at mid-span,L/4,3L/4,L/8 and 7L/8,and the measuring points should be arranged at these five locations for real-time monitoring.Under ambient excitation,the bridge doesn't produce torsional vibration with equal strength between lateral and vertical bending vibration,which shows that the structure has good torsional stiffness and the damping ratios are in a reasonable range.Using the modified modal parameters,the frequency correlation is reduced from 55.2%to a mini-mum of 0.6%.The numerical results are basically consistent with the experimental results,which means parameters still have physical meaning.The modified finite element model,which can be used as a theo-retical model for the follow-up detection of bridges,can accurately reflect the low-order dynamic charac-teristics of the structure:the maximum correlation is-2.4%,the minimum is 0.6%,and the correlation is within±5%.[Conclusions]The dynamic performance of Changhong Bridge is good,and the modified finite element model fits the actual bridge.
environmental excitation methoddynamic characteristicsfinite element model updatingfre-quency correlation
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