Numerical and Experimental Investigation of an Extradosed Cable-Stayed Bridge in Urban Rail Transit Under Dynamic Train Load

With the urban rail transit construction boom, more and more extradosed cable-stayed bridges have been built and put into service in the urban rail transit lines, due to the advantages of aesthetic appearance and high stiffness. There are distinct dynamic characteristics of the metro train and extradosed cable-stayed bridge system, which have rarely been explored. This paper presents the numerical and experimental investigation of an extradosed cable-stayed bridge under dynamic train load in urban rail transit with the maximum span among its type of bridge in China. Three vehicle modes with different degrees of freedom and two bridge finite element models are adopted to perform the dynamic analysis of the metro train and extradosed cable-stayed bridge system. Moreover, the bridge is instrumented in a comprehensive field measurement campaign including ambient vibration testing, static load testing, and dynamic load testing. The collected modal parameters and static and dynamic responses of the bridge are employed to validate the established numerical models. Dynamic characteristics of the analyzed bridge are subsequently explored. In particular, dynamic effects of the main components including the main girder, pylons, and inclined cables are examined considering a variety of operational conditions. This study provides an effective method for analyzing the dynamic responses and valuable insights into the dynamic performance of large-span extradosed cable-stayed bridges under metro train load in urban rail transit.