## 3 Numerical Model  
### Establishment of Numerical Model  
There are no drawings of completed bridges to be referenced for the innovative design of the Jinghe Bridge, so the innovative design of the bridge structure needs to be verified and analyzed. The bridge structure form is relatively complex, and the finite element method has the advantage of efficient and accurate calculation, so it is widely used in bridge calculation.  
The bridge was analyzed by numerical analysis software MIDAS/CIVIL for overall structural static and dynamic analysis, and the bridge structure was simulated by spatial beam units. The numerical model of this bridge is shown in Figure 8. This model mainly controls the strength design, stress design and stiffness design of the structure. The internal forces and stress change during the assembling process of arch ribs are not considered in the model, so the analysis starts from the bridge completion stage. The coordinate system is chosen as a Cartesian coordinate system, and the direction along the bridge is defined as the \(X\)-axis direction, the transverse direction of the bridge is defined as the \(Y\)-axis direction and the direction of gravitational acceleration is defined as the \(Z\)-axis direction. The symbols of the analysis results are defined as follows: displacement is positive when it points to the same direction as the overall coordinate system, stress is positive when it is in tension, axial force is positive when it is in tension, and the positive and negative signs of bending moment are determined by the right-handed spiral criterion.  
The main arch rib, secondary arch rib, connecting rib and crossbeam are simulated by beam units, the suspenders are simulated by truss units, the main girder is simulated by a single girder; there are 1590 nodes, 1434 beam units and 58 truss units in the whole bridge. The average unit size of the main arch rib is 1 m. The average unit size of the secondary arch ribs is 1 m. The average unit size of connection ribs is 0.6 m. The average unit size of the main girder is 1.25 m. The average unit size of the wind brace is 1.4 m. Each suspender is a single unit. In order to make unit stiffness and density correspond to actual engineering, stiffening ribs and diaphragms of arch ribs and the main girder are considered in unit sections.  
A longitudinal floating system was adopted for the bridge, and super-high-damping rubber (SHDR) bearings were adopted as bearings. Super-high-damping rubber (SHDR) bearings have the advantages of the excellent effect of seismic isolation and strong dissipation of seismic energy, so SHDR bearings were selected for the bridge. According to the bearing carrying capacity requirements, two types of bearings were selected, namely SHDR620 \(\times\) 620 \(\times\) 223 and SHDR770 \(\times\) 770 \(\times\) 256. The SHDR bearings in the finite element model are simulated by elastic connection, and the mechanical property parameters of the SHDR bearings are shown in Table 2. The connection between the arch ribs and the earth's rigid body is simulated by using general nodal support. The calculation method is the finite element method, and the analysis type is linear static analysis.