Application of transmissibility measurements to operational modal analysis of railway, highway, and pedestrian cable-stayed bridges

Abstract

Two transmissibility-based operational modal analysis (TOMA) schemes, i.e., the classic TOMA method utilizing measurements under multiple loading conditions, and the power spectral density transmissibility (PSDT) method resorting to multiple reference outputs under one loading condition, are further investigated in this study. For the classic TOMA approach, the issue of requiring multiple loading conditions is properly addressed in ambient vibration testing. Based on the unique properties of transmissibility, the frequencies can be extracted by varying either loading conditions or reference outputs, while the mode shapes can be estimated by a singular value decomposition of the transmissibility matrix. The applicability of TOMA approaches is evaluated through three typical large-scale cable-stayed bridges, including a railway bridge, a highway bridge, and a pedestrian bridge. A comparative study of these large cable-stayed bridges is carried out to gain more insights into the dynamic properties of large-scale cable-stayed bridges.