Modal frequency shift analysis for prestressed concrete beams developed by integrity loss

The paper presents a method of initial analysis of the modal parameter change (e.g. modal frequency shift) due to progressive integrity loss for prestressed concrete beams (sensitivity analysis). A global rescaling method of the numerical modal frequency set was proposed in order to fit the real vibration components determined experimentally. The aim of simulation is numerical determination of frequency modal components and modes for specific boundary conditions, determined by the tested element support system. On the basis of static and dynamic FEM simulation results the optimal location of excitation points, location of transducers recording structure vibration response can be determined. The presented methodology can be helpful and is necessary for determination of possibilities of application of VA methods for testing the prestressed concrete structures.