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Fatigue of steel bridge infrastructure
Published in Hyun-Moo Koh, Dan M. Frangopol, Bridge Maintenance, Safety, Management, Health Monitoring and Informatics, 2008
Hyun-Moo Koh, Dan M. Frangopol
Condition assessment and extraction of dynamic properties of a two spans simply supported concrete post-tensioned skew bridge in the middle of Isfahan-Tehran highway during repair operation, step-by-step, is discussed in this paper. The repair operation was carried out in three main steps. First, the asphaltic pavement was removed, then the expansion joints was removed and repaired, and finally the old neoprene elastomeric bearing was replaced with the new ones. For extraction of modal properties of the bridge, the Operational Modal Analysis technique was used. Moreover, the effect of step-by-step repair operation and number of the bearings is considered using several modal tests of the bridge during repair operation. Finally, an FE model of the bridge was constructed and the effect of shear modulus of elastomeric bridge bearing on dynamic characteristics of the bridge was studied in detail.
Study on the dynamic behaviour of Bafgh-Bandar Abbas lane railway bridge for structural health monitoring purpose
Published in Australian Journal of Structural Engineering, 2023
Amir Pourtarki, Habib Badri Ghavifekr, Hasan Afshin
Connections between reinforced concrete piers and steel truss of the bridge are bearing connections (elastomeric bridge bearing) and not fixed connections. That means, for the steel truss, free displacement in the positive vertical direction is possible but not in the negative vertical direction (Figure 3). Direct calculation of natural frequencies, in this case, would not be suitable and effective because it is not possible to apply the influence of this type of connection by such a calculation. Consequently, a time-dependent transient analysis of the train movement on the bridge is used for determining the natural frequencies and the vibration mode shapes. So, a train movement on the undamaged bridge model is simulated, and the vibration displacements of all bridge truss connections are extracted while the train crossing and free vibrations after train crossing.