Investigation on the performance of improved concrete bridges with rotary friction dampers

The inevitable occurrence of earthquakes and the infliction of great human and financial losses, especially devastating earthquakes that have occurred in recent years in different parts of the world, has emphasized the need to find a suitable and reliable solution to strengthen structures against this natural phenomenon. The use of dampers as one of the methods of passive control of structures due to reliable behavior, optimal strength and low maintenance has been considered by many engineers in recent years. Despite its relatively widespread use in buildings, the use of dampers in bridges is not common yet. The purpose of this study is to investigate the effect of using rotary friction dampers as an energy dissipation system in concrete bridges as a suitable solution to improve the seismicity of existing bridges against earthquakes. In this study, modeling has been performed on four bridge samples, with span dimensions of 20 meters and 30 meters and with three and five spans. Using time history analysis, the amount of base shear and maximum displacement have been calculated as the main parameters that have a significant impact on the failure of the stairs. According to the results, the shear force changes decrease by about 10 to 17% with increasing the span length from 20 m to 30 m. Moreover, the displacement of the bridge deck decreases about 4 to 15% by increasing the span length from 20 meters to 30 meters. In addition, by increasing the number of bridge spans from 3 to 5, a maximum increase of 11% is created in the above parameters.