公路工程

为适应高速铁路线路规划需求，某大跨连续刚构拱桥边跨采用曲线梁、中跨拱肋采用直线梁，导致悬臂施工阶段存在非对称性的特点，尤其最大悬臂阶段受力最为不利，且曲率半径的减小将加剧墩顶受力不利状态。因此，以该高速铁路大跨曲线连续刚构拱桥为研究对象，建立6种不同曲率半径的全桥有限元模型及两种曲率半径的墩顶0号块精细化实体模型，系统分析在最大悬臂阶段曲率半径对结构内力及应力分布的影响规律。结果表明：随着曲率半径的减小，边跨曲梁扭矩和横向弯矩均增大，其中0号块影响最大；双肢薄壁主墩的横向弯矩也随之增加，靠近曲梁的左肢墩增幅较右肢墩更为显著。0号块应力受曲率半径影响呈现边跨至中跨递减趋势，顶底板、腹板、横隔板及拱脚的最大压应力不同程度地增加，应力集中区域扩大，进一步加剧0号块在最大悬臂阶段的不利状态。研究成果为同类桥梁的精细化设计与施工控制提供了参考。

To meet the planning requirements of high-speed railway lines, a long-span continuous rigid-frame arch bridge adopts curved girders for the side spans and straight girders for the arch ribs in the main span, this results in asymmetric characteristics during the cantilever construction phase, particularly at the maximum cantilever stage, where the mechanical behavior is most unfavorable. Additionally, a reduction in the curvature radius exacerbates the unfavorable stress conditions at the pier top. Therefore, takes this high-speed railroad large-span curved continuous rigid arch bridge as the research object, establishes 6 different radii of curvature of the whole bridge finite element model and two radii of curvature of the top of the pier No. 0 block refinement of the solid model, and systematically analyzes the radius of curvature in the stage of the maximum cantilever on the structure of the internal force and the distribution of the stresses of the influence of the law. The results show that: as the radius of curvature decreases, the side span curved beam torque and transverse bending moment increase, of which Block 0 has the greatest influence; the transverse bending moment of the double-limb thin-walled main pier also increases accordingly, and the increase of the left-limb pier near the curved beam is more significant than that of the right-limb pier. Block 0 stresses by the radius of curvature show the trend of decreasing from the side-span end to the middle-span end, and the maximum compressive stresses of the top and bottom plates, the webs, the transverse partitions and the foot of the arches increase to different degrees, the stress concentration area is enlarged, which further aggravates the unfavorable condition of Block 0 at the maximum cantilever stage. The research results provide a reference for the fine design and construction control of similar bridges.