Abstract:

The stress conditions and force transmission mechanisms of the steel-arch box and concrete arch foot junction in a flat arch bridge were studied in-depth， Using a 196m span flat arch bridge in Guangdong as the engineering background， a detailed finite element model of the steel-concrete combined structure was established on the Abaqus platform. The stress levels and distribution patterns of the model were analyzed under six adverse working conditions. Additionally， a scaled-down model with a ratio of 1：8 was used to study the stress conditions of the segment-scale model under various working conditions. The research results indicate that under the six loading conditions， the maximum stress occurs at the bottom plate of the steel arch box， which is the primary load-bearing component， and the maximum stress does not exceed 120 MPa. The stress level of the concrete bearing platform is relatively small， with the maximum stress not exceeding 0.73 MPa. From the self-loading end of the steel arch box to the concrete bearing platform， the axial compressive stress shows a decreasing trend. During loading， the steel arch box primarily transfers the applied load to the concrete bearing platform through the bottom plate of the steel box and the web plates near the bottom plate. Under all test conditions， the stress level at the steel-concrete junction is relatively low， and most of the stress from the steel arch box bottom plate is distributed to the concrete bearing platform through components such as PBL shear keys， bearing plates， intensified stiffeners， and through reinforcement.

Key words: flat arch bridge, arch foot, steel-concrete joint section, model test, finite element