Experimental and numerical study on a universal distorted model design strategy for the box girder with the double bottom under the bending moment considering the ultimate strength and buckling collapse modes, Part 1: scaling strategy

Abstract

The ultimate bending moment and buckling collapse modes are critical factors influencing the progressive collapse behavior of the hull girder. Combined experimental and numerical analyses have typically provided robust insights into such non-linear mechanical performance. To address challenges in loading, specimen arrangement, data acquisition, and other issues encountered in the full-scale prototype experiments, scaled model experiments are commonly employed. Specifically, distorted models with unequal scale ratios in geometric dimensions and plate thickness are typically used to meet the limitations of loading capacity and the requirements of construction technology. To accurately reveal the ultimate load-carrying capacity and the buckling collapse modes of the prototype, this study proposes a universal scaling design strategy for distorted box girder models used in experiments. The similarity law for achieving the similarity in the ultimate bending moment and collapse modes of the box girder includes the similarity in section properties of the girder and the slenderness of the local stiffened plate. Due to the distortion caused by unequal scaling, the similarity in section properties will be broken. To meet the requirement of the similarity law, this study focuses on the scaling strategy to achieve similarity in the section properties of the deck and bottom simultaneously. A series of comparative scaling strategies were proposed based on the consideration of gradual improvement. Finally, the proposed scaling strategy was verified using numerical results to demonstrate its applicability to any bending case.