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  Volume 2, Number 4, October 2017, pages 257-271
DOI: https://doi.org/10.12989/acd.2017.2.4.257
 


3D simulation of railway bridges for estimating fundamental frequency using geometrical and mechanical properties
Adel Mahmoudi Moazam, Nemat Hasani and Mahdi Yazdani

 
Abstract
    There are many plain concrete arch bridges in Iran that have been used as railway bridges for more than seventy years. Owe to the fact that these bridges have not been designed seismically, and even may be loaded under high-speed trains, evaluation of fundamental frequencies of the bridges against earthquake and high-speed train vibrations is necessary for considering dynamics effects. To evaluate complex behavior of these bridges, results of field tests are useful. Since it is not possible to perform field tests for all arch bridges, these structures should be simulated correctly by computers for structural assessment. Several parameters are employed to describe the bridges, such as number of spans, length of spans, geometrical and material properties. In this study, results of field tests are used for modal analysis and adapted for 64 three dimensional finite element models with various physical parameters. Computer simulations show length of spans has important effect on fundamental frequencies of plain concrete arch bridge and modal deformations of bridges is in longitudinal and transverse directions. Also, these results demonstrate that fundamental frequencies of bridges decrease after increasing span length and number of spans. Plus, some relations based in the number of spans (n) and span length (l) are proposed for calculation of fundamental frequencies of plain concrete arch bridge.
 
Key Words
    plain concrete arch bridges; three dimensional finite element modeling; modal analysis; fundamental frequencies
 
Address
Adel Mahmoudi Moazam: Research Institute of Shakhes Pajouh, Esfahan, Iran
Nemat Hasani: Abbaspour School of Engineering, Shahid Beheshti University, Tehran, Iran
Mahdi Yazdani: Department of Civil Engineering, Faculty of Engineering, Arak University, Arak, Iran
 

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