铁道建筑

为了解大跨度铁路单索面预应力混凝土矮塔斜拉桥主梁局部受力行为，依托隆叙铁路（隆昌—叙永）沱江特大桥主桥工程，建立全边跨三维实体有限元模型，分析S1、S11号斜拉索索力最大工况下边支点反力和主梁截面应力，并与全桥三维杆系有限元模型的分析结果进行对比，验证实体有限元模型的正确性，进而分析边支点隔板、索梁锚固结构和斜杆受力情况，以及斜杆箱梁剪力滞效应。结果表明：边支点隔板、索梁锚固结构和斜杆均以受压为主，局部有水平可控的拉应力，通过合理配置普通钢筋可保证结构受力安全；除边支点和固结约束边界附近箱梁外，有索区和无索区斜杆箱梁剪力滞系数在0.91～1.14；创新地采用单索面、轻量化斜杆替代索梁锚固横梁和隔板等新技术，结构传力明确，安全可靠。

To investigate local stress behavior of the main girder of long-span railway prestressed concrete extradosed cable-stayed bridge with a single cable plane, relying on the project of Tuojiang bridge's main bridge of LongchangXuyong railway, the three-dimensional solid finite element model of the side span was established. The reactions at the side supports and the cross-sectional stresses of the main girder under the maximum cable force conditions of stay cables S1 and S11 were analyzed, and were compared with the analysis results of the three-dimensional rod system finite element model of the whole bridge to verify the correctness of the solid finite element model. Furthermore, the stress conditions of the side support diaphragms, cable-girder anchorage structures, and diagonal rods, as well as the shear lag effect of box girder with diagonal rods were analyzed. The results indicate that the side support diaphragm, cablegirder anchorage structure and diagonal rods are primarily under compression, with controllable localized tensile stress, and their safety can be ensured through reasonable reinforcement configurations. Except for box girder near the side support and fixed-boundary constraints, the shear lag coefficient of box girder with diagonal rods in cable and non-cable zones range between 0.91 and 1.14. Innovative use of single-cable plane and lightweight diagonal rods instead of cablegirder anchoring beams or diaphragms provides clear load transfer, ensuring structural safety and reliability.