Calculation of load-carrying capacity of old railway masonry arch bridges as crucial infrastructures is one of the vital issues in the railway industry. The field test of the 2PL20 bridge reveals important properties such as the initial stiffness and cracking pattern, but the ultimate capacity of the bridge under static loading was not achieved due to the field limitations. Therefore, the present study aims to predict the total nonlinear response of the 2PL20 bridge up to the failure status. All the geometrical characteristics of the 2PL20 bridge are modeled precisely and the failure state is predicted using the three-dimensional nonlinear finite element analysis. Moreover, to determine the load-carrying capacity of the 2PL20 bridge, the behavior of materials is regarded nonlinearly in which the Williams and Warnke and the Drucker-Prager failure criteria are taken into account for concrete and soil materials, respectively. To obtain precise results of ultimate capacity of the 2PL20 bridge under field test, the vertical and horizontal displacements of the crown on the northern span are chosen as the calibration criterion and, consequently, the vertical and horizontal load-deformation curves are verified based on the field test results. The obtained results indicate that the load-carrying capacity of the 2PL20 bridge equals 8880 kN under the static field test. Finally, the calculated safety factor is equal to 3.2 and increasing axial load up to 35-ton is admissible based on UIC 776-1 for a 25-ton axial load.

计算作为重要基础设施的旧铁路砌体拱桥的承载能力是铁路行业的重要问题之一。2PL20桥梁的现场测试显示了重要的性能，例如初始刚度和裂纹模式，但是由于现场限制，未达到桥梁在静态载荷下的极限承载力。因此，本研究旨在预测2PL20电桥直至故障状态的总非线性响应。2PL20桥的所有几何特征都经过精确建模，并使用三维非线性有限元分析来预测失效状态。此外，为了确定2PL20电桥的承载能力，非线性地考虑了材料的性能，其中分别针对混凝土和土壤材料考虑了Williams和Warnke以及Drucker-Prager破坏准则。为了获得2PL20桥在现场测试中的极限承载力的精确结果，选择了北跨上的拱顶的垂直和水平位移作为校准标准，因此，基于荷载作用下的垂直和水平荷载-变形曲线进行了验证。现场测试结果。所得结果表明，在静态试验中，2PL20桥的承载能力为8880 kN。选择北跨上冠的垂直和水平位移作为标定准则，并根据现场测试结果验证垂直和水平载荷-变形曲线。所得结果表明，在静态试验中，2PL20桥的承载能力为8880 kN。选择北跨上冠的垂直和水平位移作为标定准则，并根据现场测试结果验证垂直和水平载荷-变形曲线。所得结果表明，在静态试验中，2PL20桥的承载能力为8880 kN。。最后，计算得出的安全系数等于3.2，并且对于25吨的轴向载荷，基于UIC 776-1，允许将轴向载荷增加到35吨。