Research on shear stress of non-prismatic single-box-multi-cell composite box girders with CSWs

Limited research has explored the influence mechanisms of internal forces and girder geometric properties on the distribution of shear stress (DSS) within the cross-section of non-prismatic single-box multi-cell composite box girders with corrugated steel webs (SBMC-CBGCSW). Therefore, the purpose of this study is to bridge this gap. According to the equilibrium of infinitesimal elements and reciprocity theorem of shear stress, an analytical formula was first derived for calculating shear stress within the cross-section of non-prismatic SBMC-CBGCSW. Then, the influence mechanisms of internal forces and girder geometric properties on the DSS were investigated. Based on these findings, the shearing bearing ratio (SBR) of the bottom flange (BF) was calculated, and two simplified shear stress calculation methods considering the Resal effect were proposed. Finally, the accuracy of derived formulas was validated against published experimental data and numerical results. Results show that: (1) the shear stress obtained from proposed formulas agreed well with experimental data and numerical results, with discrepancies generally within an acceptable range of approximately 5 %; (2) the DSS is influenced by the interaction of internal forces, the change rate of girder height, and the change rate of BF thickness; (3) the BF may experience the maximum shear stress under the combined action of negative moment, compressive axial force, and downward shear force, where the SBR may reach its peak value. This research advances the understanding of DSS of non-prismatic SBMC-CBGCSW and offers simplified methods for shear stress calculation, providing practical tools to improve the design of the non-prismatic SBMC-CBGCSW.