PSI - Issue 64

Maciej Kulpa et al. / Procedia Structural Integrity 64 (2024) 1339–1346 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

1341

3

concrete composite system. However, the need to control the pipeline and access to it during an emergency forced a different slab solution, not connected to main girders and easy to dismantle. At the same time, cover panels not connected to the main girders means that they will not contribute to the load-carrying capacity of the girders and will be a ballast for the existing structure. For this reason, it was decided to use a lightweight structure that would also be easy to dismantle in the event of a pipeline emergency (Yang et al., 2017). After performing static and strength calculations, it turned out that the load capacity of the existing steel plate girders was not sufficient. It was necessary to strengthen them. Increasing the cross section of the girders and thus increasing their depth by 48-55 cm, sufficiently increased the load-carrying capacity of the existing steel structure. The additional upper flanges were horizontally braced with I cross beams and X-arranged angles. 12 cm thick FRP deck panels were designed to be placed on new upper flanges; however, no composite action with the girders was introduced. Owing to the application of the FRP composite, the self-weight of the new deck was minimised while increasing its durability. The cross section of the reconstructed structure is shown in Fig. 2.

Fig. 2. The cross-section of the reconstructed structure (elements added to existing structure are marked in red)

Due to the heat pipeline chambers located at the ends of the existing supporting structure, its reconstruction required the addition of three small spans, leading a bicycle path above the chambers. On the western side, a simply supported span of 18.49 m was added, and on the eastern side, two continuous spans of 5.44 m and 4.76 m were built. All added spans are fully made of FRP composite as a sandwich slab. They are also chosen for easy disassembly when needed, mainly because of the low weight of the FRP spans. Finally, after reconstruction, the total length of the new bridge increased by almost 30 metres and is now 106.4 m and consists of six spans: 18.49 m + 22.75 m + 30.03 m + 23.43 m + 5.44 m + 4 .76 m. The end supports were also adapted to the new superstructure: the upper part of the abutments was completely replaced to adapt the access roads and the space behind the support to new additional spans. The intermediate piers remained unchanged.