*Article* **Research on Loading Scheme for Large-Scale Model Tests of Super-Long-Span Arch Bridge**

**Yonghui Fan, Jianting Zhou, Chao Luo, Jun Yang \*, Jingzhou Xin and Shaorui Wang**

State Key Laboratory of Mountain Bridge and Tunnel Engineering, Chongqing Jiaotong University, Chongqing 400074, China; fyh1995@mails.cqjtu.edu.cn (Y.F.); jtzhou@cqjtu.edu.cn (J.Z.); luochao@mails.cqjtu.edu.cn (C.L.); xinjz@cqjtu.edu.cn (J.X.); ruiruiplace@163.com (S.W.) **\*** Correspondence: yangjun@mails.cqjtu.edu.cn; Tel.: +86-152-1503-5160

**Abstract:** A reasonable and efficient loading scheme is needed to guarantee the success of large-scale bridge tests. In this study, an array-type, self-balancing pulley-group loading system was designed based on the world's largest spanning arch bridge using a 1:10 scale model test. Automatic statistics of the required load at each loading point were realized using ANSYS, and a load optimization algorithm for loading points at different construction stages was proposed. Tests were carried out separately for the loading system using a single set of pulley groups and an array-type pulley group. Finite element models of the model bridge and the original bridge were established separately using ANSYS, and the stress results of different components during different construction stages of the main arch ring were compared. The research results show the following: (1) The load magnification factor of the single-pulley-group loading device is approximately 6.6 times, with a mechanical efficiency of 94.26%. (2) In the array-type loading system, the actual load at each loading point can reach the design value. The self-balancing characteristic of this system can eliminate the impact of vertical deformation of the structure on loading accuracy, verifying the reliability of the system. (3) The simulation results of the original bridge and the model bridge coincide well, and the stress of each component during the construction process has the same trend. At key construction stages, the maximum relative errors of the stress results of the rigid steel frame and the concrete inside the pipe of the two bridges are 8.33% and 9.34%, respectively, and the maximum absolute error of the bottom plate concrete is 0.66 MPa, verifying the correctness of the counterweight-optimization method. The loading scheme proposed in this paper can provide a reference for the design of loading systems with the same type of scale model test.

**Keywords:** rigid-frame arch bridge; scale model test; test design; loading system; weight calculation method
