Bridge crossing monitoring, natural frequencies, superstructure, dynamic load, viscoelastic model, vertical displacement

The present investigation is devoted to the study of the dynamic behavior of a singlespan low-water bridge and the assessment of the possibility of detecting defects appearing during its operation. The relevance of the work is confirmed by the fact that the water level for low-water bridges does not allow for a visual inspection and instrumental examination of the lower part of the superstructure and the girder beams of the supports. Since such bridge crossings do not take into account the possibility of ice passage, high waters and water transport, generalized viscosity and elasticity parameters are introduced into the viscoelastic model of the superstructure support, which can allow these factors to be taken into account. A beam system has been adopted as the design scheme, to describe the deformation of which equations for a beam or a strip plate can be applied, which can be reinforced with an additional structure to increase rigidity. In this paper, analytical and graphical dependences are obtained for the geometric and dynamic characteristics of the deformation of the superstructure, with the help of which it is possible to assess the operational condition of the bridge by the natural frequencies of vibrations of the superstructure.

Loktev Alexey Alekseevich Doctor of Physical and Mathematical Sciences, Professor, Russian University of Transport (MIIT), Moscow, Russia, Professor, National Research Moscow State University of Civil Engineering, Moscow, Russia, 

Lilia Alekseevna Illarionova, Senior Lecturer, Russian University of Transport (MIIT), Moscow, Russia 

Barakat Ahmad, PhD student, National Research Moscow State University of Civil Engineering, Moscow, Russia