An improved scaled model design method for box girders under hogging moment considering the ultimate bending moment and collapse modes

An improved scaled method for box girders subjected to a hogging moment is developed based on maintaining the similarity of section properties and slenderness. The section area, moment of inertia, section modulus, plate slenderness, and column slenderness are considered as factors influencing the determination of the ultimate hogging moment. A smaller scale ratio is required to reduce the load-carrying capacity of scaled models, which poses challenges in ensuring that the designed scaled model aligns with the requirements of the construction process. Based on the discussion of several design strategies, a reasonable design of scaled models can be achieved through the following steps. First, the similarity of the plate slenderness is maintained by adjusting the number of stiffeners. Secondly, the similarity in column slenderness is maintained by adjusting the plate length. Third, the similarity of the section properties is improved by maintaining the similarity of the area of the local part. Simultaneously, the scaling strategy of the stiffeners is changed to ensure the similarity of the collapse modes. Fourth, modification methods for the similarity of the moment of inertia and section modulus are proposed to further improve the similarity of the ultimate bending moment. Furthermore, the criteria for choosing a modification of the section modulus and moment of inertia were proposed.