Nonlinear Analytical Model for Rail Deformation of CRTS-III Slab Track Simply-Supported Bridge under Lateral Misalignment
Zhishui Sheng1, Xiang Liu2,*, Fangwen Ge2, Xiewei Luo2
1 Rail Transit Branch, China Communications Construction Company Limited, Beijing, China
2 College of Civil Engineering, Fujian University of Technology, Fuzhou, China
* Corresponding Author: Xiang Liu. Email: 
(This article belongs to the Special Issue: Repair, Seismic Performance, and Functional Recovery of Structures)
Structural Durability & Health Monitoring https://doi.org/10.32604/sdhm.2026.085027
Received 04 May 2026; Accepted 10 July 2026; Published online 07 September 2026
Abstract
After a strong earthquake, a simply supported bridge may retain lateral residual deformation. This kind of deformation can seriously affect the track geometry. To better check whether the track is still safe after an earthquake, this study builds a new nonlinear analytical model. The model covers the whole rail-fastener-beam system and includes the complete process of fastener failure. First, based on experimental data, we create a three-stage nonlinear mechanical model for the fasteners. The three stages are elastic-slip stage, constraint-activation stage, and brittle-failure stage. Second, we use an analytical method to get the governing equations of the system. Then we solve these equations with an incremental iterative method that includes relaxation factors. Next, we look at two typical post-earthquake situations. One is lateral bridge displacement. The other is bridge rotation. We check how each one affects rail deformation and fastener force. The main findings are: Under lateral loads, the fasteners show a clear nonlinear damage evolution. Their ultimate capacity is 82.80 kN. Lateral displacement is the main reason for fastener damage. When the displacement reaches 60 mm, the fasteners fail. At that point, the track loses all constraint. On the other hand, bridge rotation has only a very small effect on the track structure. In this case, the system stays safe within the elastic range. This model gives us a theoretical basis for quickly checking the track geometry of high-speed railways after an earthquake.
Keywords
Simply supported bridge; post-earthquake residual deformation; fastener failure; nonlinear analytical model; track geometry
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