In situ evaluation of dynamic characteristics of prefabricated ballastless track slab using EMA and OMA techniques

Abstract

Abstract This study focused on the prefabricated ballastless slab tracks first applied in urban rail transit of a city in China. By combining the experimental modal analysis (EMA) and operational modal analysis (OMA) techniques, we evaluated the dynamic characteristics of the tracks using the eigensystem realization algorithm and stochastic subspace identification algorithm to identify modal parameters. This study attempted to determine the characteristics and correlation of the two modal analysis methods to comprehensively reflect the dynamic characteristics of the track slabs. We established a detailed finite element model to analyze the influence of the construction method and structural characteristics of the track slabs on the modal parameters. The results show that the in-situ testing of the track slab modes were subject to the influence of many uncertain factors, resulting in differences between the numerical calculation-based ideal mode shapes and the actual EMA- and OMA-based counterparts.