Nonlinear force driven coupled vertical and torsional vibrations of suspension bridges, when the frequency of an external force is approaching one of the natural frequencies of the suspension system, which, in its turn, undergoes the conditions of the one-to-one internal resonance, are investigated. The generalized method of multiple time-scales is used as the method of solution. The damping characteristics are described by the rheological model involving a fractional derivative, which is interpreted as a fractional power of the differentiation operator. The main subject of this research is the numerical analysis of the influence of the fractional damping on the dynamic behavior of a suspension combined system.