PSI - Issue 64

Cedric Eisermann et al. / Procedia Structural Integrity 64 (2024) 1224–1231 Eisermann et al./ Structural Integrity Procedia 00 (2019) 000–000

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Fig. 2: Cross-section of the Nibelungen Bridge

In the early 2000s, a recalculation of the bridge was carried out, which revealed deficiencies in the bending and shear load-bearing capacity of the superstructure. The bending load-bearing capacity was improved by retrofitting external tendons. However, the shear load-bearing capacity remained insufficient due to a lack of technical and economic rehabilitation solutions. As a result, the remaining service life of the bridge was set at 15 to 20 years in 2010. Recently, this conservation strategy has been further investigated to extend the service life of the bridge (Kang et al. 2024). Initial measures, including a structural health monitoring system, a digital twin, and a geometric survey, have been conducted on a pilot area of the structure (Fig. 1). Subsequent investigations are limited to this area. According to Brühwiler (2023) the Nibelungen Bridge has a high self-weight, with approximately 86% of the total load attributed to permanent loads. Therefore, precise calculation of the dead load and adjustment of the associated partial factor can play a major role in proving the load-bearing capacity of the bridge. 3.2. Geometry models As part of the SPP 100+, multimodal data acquisition methods were used to capture the precise geometry information of the bridge and further create 3D models.

Fig. 3. (a) As-design model; (b) As-ismodel

The as-designed model was created using the BIM software Revit based on the inventory technical design drawings. The initial step involved extracting the varying cross-sectional parameters for each cantilever section of the superstructure (i.e., box girder height and bottom slab thickness) from the formwork plan. This data was then recorded in a table and linked to a parameterized cross-section. The 3D model of the superstructure was obtained by interpolating and extruding the cross-section along the bridge axis. The substructures (i.e., piers and abutments) were created as separate sub-models and inserted into the main model at the appropriate stations along the bridge axis.