Effects of viscoelastic supports on the behavior of bridges under moving vehicles

One of the most important problems facing structural engineers is the analysis of dynamic behavior of bridges subjected to moving vehicles. In addition, viscoelastic supports under bridges change their dynamic behavior under passing traffic loads. This paper presents how to model a bridge with viscoelastic supports and how the maximum dynamic stress of bridges changes during the passing of moving vehicles. Furthermore, this paper presents an algorithm to solve the governing equation of the bridge with viscoelastic supports as well as the equation of motion of a real European truck with different speeds, simultaneously. Using viscoelastic supports with appropriate characteristics can make a significant difference in the magnitude on the maximum dynamic stress of bridges. By finite difference method, it will be shown that how much the stiffness and damping of viscoelastic supports should be to have less impact and dynamic stresses in the bridges. It will be demonstrated that using viscoelastic supports can decrease the local maximum DAFs in the case of short and medium spans up to 5%. This study becomes more important where vehicle speeds are considerably high; therefore, the consequences of a full-length analysis with viscoelastic supports must be used to design safe bridges.