Reinforcing strategies for double-coped beams against local web buckling

This paper presents a comprehensive numerical study on the strength and behaviour of double-coped beams (DCBs), with the focus on reinforcing strategies against local web buckling. Four reinforcement types, namely, longitudinal web stiffener (Type A), combined longitudinal and vertical web stiffeners (Type B), vertical and double longitudinal web stiffeners (Type C), and full-depth doubler plate (Type D), are considered. Through examining a suite of validated numerical models with a spectrum of cope details, it is found that the considered reinforcement types are in general effective, especially for the models with long or deep copes. Depending on the cope details and stiffener type, a series of failure modes, including local web buckling, web shear yielding, web shear buckling, tensile fracture of the bottom cope corner, and web crippling, are identified, and the effectiveness of the different reinforcement types on preventing or postponing these failure modes is discussed in detail. A preliminary design rule for checking the capacity of the reinforced coped section is also proposed in the paper, and additional analysis is performed to further evaluate the influences of varying reinforcement dimensions and boundary conditions on the ultimate capacity of the DCBs. Based on the numerical analysis, a set of prescriptive recommendations on reinforcement details is finally proposed, offering a simple yet safe guidance for new design or upgrade of DCB members.