The “direct method” is commonly employed to establish analytical models for assessing the stress state of curved beam bridges during incremental walking-launch construction. However, this approach often involves cumbersome mathematical derivations for curved elements and entails high computational costs. To overcome these limitations, this study proposes a “straight-line substitution method” and examines its applicability for analyzing the mechanical behavior of a composite system consisting of steel box girders and steel guide beams during the curved beam walking-launch process. Using a curved river-crossing bridge as a case study, finite element analysis (FEA) is conducted to compare the mechanical responses of the composite system under various loading conditions obtained from the proposed method and the conventional direct method. Furthermore, a parameter analysis is performed to investigate the influence of variations in beam height and width on the consistency between the two methods. The results demonstrate that the straight-line substitution method yields computational outcomes highly consistent with those of the direct method across different beam heights and widths. Moreover, the proposed method exhibits superior modeling efficiency compared to the direct method.
Li et al. (Sun,) studied this question.