为探究坦拱桥钢拱箱与混凝土拱脚结合段的受力情况与传力机理，以广东某计算跨径196 m的坦拱桥为工程背景，基于Abaqus平台，建立钢-混组合结构拱脚精细化模型，分析6种不利工况下有限元模型的应力水平及分布规律；同时制作缩尺比为1∶8的局部模型进行多工况加载试验，研究拱脚钢-混结合段在不同工况下的受力情况。研究结果表明：各加载工况下，钢拱箱底板应力最为显著，为主要承力构件，最大应力为-116.875 MPa；钢箱底板应力分布情况中，底板加劲肋起主要作用，其应力水平相较于其他部位最为突出，靠近钢拱箱底板的腹板区域应力次之，各工况下最大应力为-32.16 MPa；钢拱箱顶板应力水平较低；混凝土承台整体测点应力值均较小，最大应力不超过-0.73 MPa；钢拱箱自加载端到混凝土承台端的轴向压应力呈现减小趋势，钢拱箱在受力时主要通过钢箱底板以及靠近钢箱底板的腹板将所受荷载传递到混凝土承台处；各试验工况下，钢-混结合段处应力水平相对较低，来自钢拱箱底板的大部分应力经由PBL剪力键、承压板、加密加劲肋、穿越钢筋等组件分散到混凝土承台。

To investigate the stress behavior and load-transfer mechanism at the steel-concrete joint segment of a flat arch bridge, this study takes a flat arch bridge in Guangdong with a calculated span of 196 m as the engineering background. Based on the Abaqus platform, a refined finite element model of the steel-concrete composite arch abutment was established to analyze the stress level and distribution characteristics of the structure under six unfavorable load cases. In addition, a 1∶8 scaled patial model was fabricated for multi-condition loading tests to study the mechanical behavior of the steel-concrete joint segment under different scenarios. The results indicate that, under all loading cases, the stress in the bottom plate of the steel arch box is most significant, making it the primary load-bearing component, with a maximum stress of -116.875 MPa. In the stress distribution of the bottom plate, the stiffening ribs play a major role, exhibiting the most prominent stress levels compared to other areas. The web area adjacent to the bottom plate of the steel arch box experience the next highest stresses, with a maximum value of -32.16 MPa across all conditions. The stress level in the top plate of the steel arch box is relatively low. The measured stress values in the concrete pile cap are generally small, with a maximum stress not exceeding -0.73 MPa. The axial compressive stress in the steel arch box gradually decreases from the loading end to the concrete pile cap end. When subjected to loads, the steel arch box primarily transfers the applied loads to the concrete pile cap through the bottom plate and the adjacent web regions. Under all test conditions, the stress level at the steel-concrete joint segment is relatively low, as most of the stress from the bottom plate of the steel arch box is dispersed into the concrete pile cap via components such as PBL shear connectors, bearing plates, densely arranged stiffening ribs, and penetrating reinforcement bars.