The vibration and noise of a structure can be mitigated by controlling the power exchange between the excitation and the remote parts. An implementation is to integrate piezoelectric materials into the host structure and to design the associated electric impedance in order to control the energy flow. In this work, built-up structures with periodical piezoelectric shunts are considered. Major efforts are devoted to develop a rapid and accurate numerical tool for the evaluation of the energy flow in this kind of built-up structures. In this method, Wave and Finite Element Method (WFEM) is employed to model the periodic substructures while Finite Element Method (FEM) is used to capture the non-periodic substructures. A modal reduction technique is introduced to WFEM accelerate the wave basis calculation. Validations are presented, attesting the accuracy of he proposed method. An application is given, where energy flow of a infinite structure with resistive piezoelectric waveguide is presented.