#structural Dynamics

ABSTRACT. Modal analysis is a very powerful experimental approach that provides direct measurement of structural dynamic characteristics of a system without any analytical assumption or analytical modeling. This approach is becoming more popular for civil engineering applications. In this paper, time and frequency domain algorithms are very briefly explained from a civil engineering application point of view. Considerations in utilizing such algorithms for civil infrastructures are also discussed. A spatial / frequency domain algorithm that is used to post-process multiple reference impact test data is presented. The method is applied and results are evaluated on a data set collected from a steel stringer highway bridge. NOMENCLATURE [A] = Unified Matrix Polynomial (UMPA) Model Coefficient for the Output [B] = Unified Matrix Polynomial (UMP A) Model Coefficient for the Input [F] = Force Matrix [H] = FRF Matri