大跨"槽型+箱型"连续混凝土梁受力与设计研究

Study on Stress and Design of Long-span"Trough+Box"Continuous Concrete Girder

针对某地公轨合建工程35+50+35 m大跨"槽型+箱型"组合截面连续混凝土梁结构体系特殊、受力行为不明确,采用ANSYS有限元软件建立三维实体模型,研究其受力行为,并对设计提出建议.研究表明:一是"槽型+箱型"组合截面满足平截面假定;二是组合截面槽型、箱型部分纵向不同截面、同一截面边或中腹板剪力分布存在显著差异;三是槽型部分边腹板与底板衔接处应力集中明显;四是槽型部分边腹板与底板衔接处应加强配筋、桥面板悬臂根部及跨中配筋可取包络设计.

Aiming at the special structural system and the unclear stress behavior of the 35 m+50 m+35 m long-span"trough+box"compound section continuous concrete girder in a highway-rail co-construction project,a three-dimensional solid model is established by using ANSYS finite element software to study its stress behavior,and the suggestions are proposed for the design.The study shows that(1)the"trough+box"compound section satisfies the plane cross-section assumption.(2)There are significant differences in shear force distribution of the side/middle webs of trough and box compound sections in different sections and the same section.(3)The stress concentration is obvious at the junction between the side web and the bottom plate of the trough part.(4)The reinforcement at the junction between the side web and the bottom plate of the trough part should be strengthened,and the envelope design of the reinforcement at the cantilever root and the mid-span of the deck slab can be carried out.