The study is devoted to the modern single shaft gas turbine rotor forced vibration frequencies and amplitudes. For such problem solution a refined mathematical model of the gas turbine rotor impellers forced vibration, taking into account the influence of constructional damping was developed. It can be used for different types of gas or even steam turbine engines. Such mathematical model is based on the exciting gas dynamic force calculation and its impact on the forced vibration processes in the rotor impellers. The studies have been held for the two main types of impeller bandages and different boundary conditions, caused by these bandages types usage. The influence of the mounting tension angle on the blades forced vibration modes and frequencies for the most hardly loaded impellers in the rotor has been determined with the recommendation of the proper tension angle value. The methodology of the impeller forced vibration amplitudes calculation with the constructional damping in the blades bandages is also developed on taking into consideration the work of friction forces. Calculated data and the given recommendations for the proper bandages mounting tension angle and boundary conditions will be used for the next stage of studies, concerning the rotor stress-strain state and fatigue strength problems.