## 1 Introduction  
With the rapid development of China's economy and the level of science and technology, transportation construction technology is also changing rapidly. In bridge construction, it is inevitable to encounter special working conditions such as rivers, valleys, railroads, heavy traffic, etc. [1; 2; 3], which require more advanced bridge construction methods [4; 5; 6]. For example, the technique of constructing horizontally swiveling overpasses [7; 8] has the advantages of high construction efficiency, low cost, a wide range of use, and so on [9; 10]. The core component is the swiveling structure in this technology [11], whose stress state directly determines the success of horizontal swiveling construction [12; 13]. The swiveling structure consists of an upper turntable, steel spherical hinges, a steel pin shaft, a lower turntable, supporting legs, a circular track, and a swiveling traction system [14]. Included among these, the steel spherical hinge serves as the main support for the connection of the upper concrete structure to the lower turntable; the stresses are not only large but also very complex. So, it is crucial to study the change rule of steel spherical hinge stress. When the center of gravity of the upper concrete structure coincides with the center of the steel spherical hinge structure, the steel spherical hinge is in a positive loading condition [15], and the bridge turning process will be very smooth [16]. However, in the actual construction process, due to the complexity of the shape of the upper concrete structure, the uneven distribution of materials, construction errors, and external uncertainties, the center of gravity of the upper concrete structure and the center of the steel spherical hinge structure will not coincide [17]. At this time, the steel spherical hinge is in the partial load condition [18], which greatly increases the load of the steel spherical hinge, and when the partial load is serious, it will lead to the structural overturning of the bridge [19]. Therefore, in this paper, through the combination of finite element simulation software and engineering measured data, the stresses on the steel spherical hinge during rotation and bias load conditions were analyzed [20], and the rule of change in stress and deformation of the steel spherical hinge was summarized. Therefore, this paper relies on the actual construction project of the transporter bridge, establishes a three-dimensional model of the whole bridge, and uses Ansys finite element simulation software to simulate the whole bridge. Analyzing the stresses on the upper turntable and the steel spherical hinge during rotation and under partial load conditions and comparing it to the measured engineering data. Thus, summarized in different working conditions, the upper turntable and steel spherical hinge stress change law and deformation. In recent years, scholars in both domestic and foreign countries have conducted in-depth studies on the changes in stress in the steel spherical hinge parts of the transverse bridges and have achieved some results. [PERSON] introduced the finite element method into the contact problem, ignoring the friction of the contact surface, and proposed a new idea to solve the spherical-hinge contact problem [21]; [PERSON] investigated the effect of friction on the steel spherical hinge, ignoring the displacement and eccentricity of the steel spherical hinge, and demonstrated that frictional resistance has a significant effect on the stresses in the steel spherical hinge [22].