ABSTRACT
This article is part of the studies of the StonArc-Rail project aimed at the experimental and numerical characterization of the structural behaviour of existing stone arch bridges in Portugal under rail traffic loading.
The paper focus the study of Côa bridge, illustrated in Figure 1, a granite stone masonry arch bridge built in the late 1940s to replace an existing steel bridge over Côa river in Beira Alta line of the Portuguese railways. The total length of the bridge is approximately 238 m, with 4.8 m width and supports one single-track. The bridge is formed by eight arches, one with span of 38 m and the rest with 20 m, which are supported onto seven piers and two abutments. The maximum height difference between the foundation and the pavement is approximately 56 m. Côa bridge. https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781315207681/cd556cd4-4dcf-4efe-8e29-56fc67b8bfbd/content/fig165_1.jpg"/>
The numerical model of Côa bridge is a threedimensional model based in the finite element method developed in ANSYS software that resulted of an upgrade of an existing model developed by Costa et al. (2013).
There were performed dynamic analyses considering train-bridge interaction. The train used in this analyses was Alfa Pendular train, the fastest passenger train operating in Portugal that can reach speeds up to 220 km/h. It is a tilting train composed by six vehicles, four motor vehicles (BAS, BBS, BBN and BAN) and two hauled vehicles (RNB and RNH). This conventional train has a total length of 158.9 m and the axle loads varies between 128.8 kN and 136.6 kN.
The numerical model consists in a simplified 3D finite element model developed in ANSYS software and developed specifically for BBN vehicle. This model is an adaptation of the model proposed by Meixedo et al. (2014).
Both numerical models of the bridge and the train were optimized based on modal information obtained from dynamic tests.
The study of the bridge response was made in terms of displacements and accelerations and considered a wide range of circulation speeds including track irregularities. For the Alfa Pendular train, accelerations were evaluated in the carbody and passengers in different vehicle locations. The dynamic responses obtained for the bridge and for the train were compared with limit values established by EN1990-Annex A2 (2005). The track stability criterion of 3.5 m/s2 was accomplished for circulation speeds up to 400 km/h. Regarding the Alfa Pendular response, some speed restrictions were also identified related to carbody accelerations for different comfort levels.
