# Development and Application of Digital Twin-BIM Technology for Bridge Management
## 4 Building Information Management
### Digital Twin of Comoro Bridge for Structural Performance Evaluation
#### 4.4.2 Structural Performance Evaluation Based on FE Analysis  
\(\bullet\) Full-Scale Model Creation for FE Analysis  
The digital twin of the Comoro Bridge, developed in a BIM tool (Revit) and supported by visual programming (refer to Figure 14), facilitated the FE analysis of the full-scale model. Subsequently, the model was exported to IFC files for integration with FE software. Following this, it was necessary to install prestressing tendons along the PC box girder sections based on the construction drawings, as depicted in Figure 15.  
Figure 14: Full-Scale Model. Figure 13: Digital twin-BIM and FEA interoperability. The Comoro Bridge model was composed of three PC-box superstructures, five piers, and two abutments as mentioned above. Each component was idealized by a solid element, and the bearing on the top of piers and abutments was idealized by spring elements, which represented the stiffness of six degrees of freedom in each direction. The prestressing tendons were idealized by the so-called embedded bar element coupled with the concrete superstructure. The embedded bar element was a virtual element representing the interaction behavior of the reinforcement inside the concrete members. * Material Properties  
The material properties of the concrete and prestressed tendons utilized for the FE analysis in this study are presented in Tables 1 and 2 based on construction records, respectively. * Boundary Conditions The boundary conditions applied in this analysis were as follows: The bottoms of pile caps and abutments were idealized as fixed supports. They were rigidly connected to the ground with translations (T1, T2, and T3) constrained, as illustrated in Figure 16. The bearings were represented by spring materials, as depicted in Figure 17. Modeling the rotational boundary conditions as fully free poses challenges, hence rotational springs were adopted with a stiffness value of \(10^{6}\) (kNm/rad) as indicated in Table 3.  
* Discretization (\"Meshing\")  
A mesh is a discrete representation of a larger geometric domain using smaller cells. Meshes are commonly employed for solving partial differential equations, rendering computer graphics, and analyzing geographical and cartographic data. Meshing divides the space into elements (or cells or zones) on which the equations can be solved, providing an approximation of the solution across the larger domain. In this study, the meshing process was performed in DIANA FEA, using a mesh size of 0.25 m and a HEX/SQUAD meshing type, as illustrated in Figure 19.  
Figure 19: Discretization. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Location**} & \multirow{2}{*}{**Direction**} & \multirow{2}{*}{**Theoretical B. C.**} & \multicolumn{3}{c}{**Analysis**} \\ \cline{3-6}  & & & \(X\) & & **B. C.** & **Stiffness** \\ \cline{3-6}  & \multirow{2}{*}{\begin{tabular}{c} Sway \\ deformation \\ \end{tabular} } & \(Y\) & \multirow{2}{*}{Fix} & \multirow{2}{*}{\
\begin{tabular}{c} Rigidly fixed \\ by spring element \\ \end{tabular} } & \multirow{2}{*}{\(10^{10}\) (\(\mathrm{kN}/\mathrm{m}\))} \\ \cline{3-6}  & & \(Z\) & & & \\ \cline{3-6}  & \multirow{2}{*}{
\begin{tabular}{c} Rotational \\ deformation \\ \end{tabular} } & \(R_{X}\) & Fix & & \\ \cline{3-6}  & & \(R_{Y}\) & Free & & \\ \cline{3-6}  & & \(R_{Z}\) & Fix & & \\ \hline \hline \end{tabular}  
* Loads  
The loads considered in this analysis are depicted in Figure 18 as follows:  
1. Self-weight (DL): represents the weight of all structural elements of the bridge.
2. Superimposed dead load (SDL): Includes the weight of the steel railing, asphalt concrete pavement, safety fences, and other components. The combined value of this load was 50 \(\mathrm{kN}/\mathrm{m}\).
3. Prestress Tendon (T): represents the tendons just after prestressing with a stress of 1295 \(\mathrm{N}/\mathrm{mm}^{2}\).  
Figure 18: Loads.  
\end{table} 
Table 3: _Cont._Analysis Type  
The types of FE analysis conducted in this study are presented in Table 4. Geometric nonlinear analyses were not performed.