PSI - Issue 64

Chongjie Kang et al. / Procedia Structural Integrity 64 (2024) 1232–1239 Chongjie Kang, Maria Walker, Steffen Marx / Structural Integrity Procedia 00 (2019) 000 – 000

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Tab. 3. Advantages and limitations of various model types used in the bridge digital twin implementations Model type and sources Advantages Limitations BIM model Jiang et al. (2021b); Boje et al. (2020) - Linking of external data sources to bridge components and sensors; - IFC-format standardizes the storage of building data; - Basis for navigating, visualizing and locating data in the frontend

- No continuously update or automated data processing; - Creating BIM models for existing structures can be time and cost-intensive. - Difficulty in distinguishing between environmental, and structural changes; - Lack of information on changes in unmonitored components; - Management of large datasets is technically challenging; - Training phase for healthy state is necessary - The result may be distorted due to simplified assumptions and uncertainties in the modeling; - Precise knowledge of the physics is required; - High computational effort for complex models is required. - Recording quality is limited by camera technology and image data analysis methods; - Information on materials and structural condition inside of the structure remains undetected; - Processing and segmentation of point clouds can involve high computational and manual effort. - Lack of interfaces for connecting different models and sources; - Lack of algorithms for synchronization of models; - Lack of unified open-source platforms and software products for model integration.

Data-driven surrogate model Rasheed et al. (2020); Ye et al. (2019)

- Monitoring data enables continuous updating; - Enables advanced data science techniques, including machine learning; - No knowledge of physical relationships required. - Provides a transparent, physically grounded basis; - Identifies critical points on the structure; - Scenario simulation is possible. - UAS assists visual inspections in difficult-to access areas; - Provides high-resolution surface capture; - Automated capture of as-built geometry facilitates derivation of updated BIM or FE models. - Takes advantages of multiple methods while mitigating their disadvantages.

Analysis model Rasheed et al. (2020); Ye et al. (2019)

3D surface model Taraben et al. (2022); Morgenthal and Helmrich (2023)

Federated model Honghong et al. (2023)

4. DT of the Nibelungen Bridge in Worms The Nibelungen Bridge Worms connects the Rhineland-Palatinate city of Worms across the Rhine with the Hessian cities of Lampertheim and Bürstadt. When it was completed in 1953, it was the third and longest cantilever bridge. The river bridge has a span configuration of approx. 101.63 m - 114.22 m - 104.25 m (Fig. 3).

Fig. 3. Side view of the Nibelungen Bridge Worms (river bridge)

The spans are each composed of two cantilever beams. They are constrained by the piers and connected in the center by vertically braced Gerber joints. In addition, there is a short span of approx. 23.22 m in front of the bridge tower on the side of the city of Worms. It serves as the counterweight for the superstructure cantilevered on the other side of the land pier. On the opposite side of the Rhine, due to a lack of sufficient space for a counterweight, the suspension had to be achieved via vertical tendons anchored to the newly installed cantilever beams of the abutment foundation (Fig. 3). This bridge has been in operation for 71 years until 2024 and underwent a fundament renovation from 2010 to 2013. It is of great cultural value for the region as well as the civil engineering community and was