A new similarity method for the ultimate strength of box girders subjected to the combined load of bending and lateral pressure

The ultimate strength is an important property for hull structures nowadays. For large-scale structures, scale models are needed to perform physical model tests. Therefore, similarity methods are especially important. Traditional similarity methods consider similarity criteria of cross-section properties, and modern similarity methods introduce some strength-related similarity criteria to consider the nonlinear collapse procedure. However, these two kinds of criteria may be conflicting and are hard to meet simultaneously. Most existing works concentrated on simple structures, like stiffened plates, due to the difficulty in meeting all the similarity criteria. In this paper, a new similarity method is proposed for box girders subjected to the combined load of bending moment and lateral pressure. The proposed method considers only the strength-related similarity criteria, ignoring the criteria of cross-section properties. The column slenderness, the plate slenderness, and the torsional slenderness are selected as the similarity parameters for every stiffened plate in the box girder. The new similarity relations of the ultimate moment and the applied lateral pressure are derived according to the proposed criteria. A structured step-by-step scale model design procedure is proposed to design corresponding scale models. 4 numerical examples are presented to show the correctness and advantages of the proposed method.