Damage of interface between slab track bases and cable-stayed bridge under train load based on fatigue cohesion model

Abstract

To investigate the fatigue damage of the interface between bases of slab tracks and the beam of a cable-stayed bridge (CSB), this study established a fatigue cohesion model based on the damage extrapolation theory. Through finite element analysis, the fatigue damage of the base interface under moving train loads was analyzed. The results showed that significant deformations occurred on the track near the piers and towers of the CSB, revealing noticeable incongruous deformations between the track and beam. Substantial stress was observed in the base and interface, which was induced by bridge deformations and approached damage criteria. The damage locations primarily occurred in the center and the ends of the base directly above the support. At the piers and towers, the fatigue life of the interface between the slab tracks and the beam was found to be 20.63 years and 45.21 years, respectively. Since the bridge deformation under train load mainly caused interface tensile cracking, the influence of normal bonding strength on interface damage was significant, while the impact of tangential bonding strength on base interface damage was less apparent. Changing the relative position of the bases and supports did not prevent damage to the base end interface completely, but can lead to an increase in fatigue life in the center significantly. Therefore, adopting a rational layout of slab tracks can effectively extend the fatigue life of the base interface. It was suggested to place base joints as close as possible to the supports at the piers and towers.