PSI - Issue 82

Valentyn Uchanin et al. / Procedia Structural Integrity 82 (2026) 288–294 Valentyn Uchanin et al. / Structural Integrity Procedia 00 (2026) 000–000

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material is French FSS of FR20 type. Excavation of the investigated sections of the pipelines was carried out to measure the stresses (Fig. 4a) using the MESTR-411 device (Fig. 4b) with a 4-pole probe at the operating frequency of 1000 Hz. Measurements were taken at 8 points in selected cross-sections of the pipeline at 30° intervals.

Fig. 4. (a) Pipeline crossing the ravine: 1 – pipeline; 2 – soil; 3 – excavation at the ravine entrance; 4 – excavation in the lower part of the ravine, and (b) EC stress analyzer of the MESTR-411 type.

Let’s consider, as an example, the results of the inspection of the pipeline section that crosses the ravine. Excavations were made at the beginning of the pipeline’s entrance to the ravine and in the lower part of the ravine. The obtained distributions of longitudinal stresses in polar coordinates in two cross-sections, 3 and 4 (Fig. 4a), of the evaluated pipe are presented in Fig. 5. From Fig. 5a, it can be seen that the pipeline in this zone is subjected to bending loads. The upper part of the pipeline is stretched, and the lower part is compressed. This distribution of stresses is characteristic of the pipeline at the entrance to the ravine (Fig. 4a). The magnitudes of the bending stresses are insignificant: up to 35 MPa in compression and only up to 27 MPa in tension. The distribution of longitudinal stresses in Fig. 5b for cross section 4 (Fig. 4a) shows that the pipeline is also under the action of a bending load, but of a different nature. The upper part of the pipeline is compressed, and the lower part is stretched. Such a distribution is characteristic of the pipeline in the middle of the ravine (cross-section 4 in Fig. 4). The magnitudes of stresses from bending are larger, but also insignificant: up to 61 MPa in compression and up to 42 MPa in tension.

Fig 5. (a) Distribution of longitudinal stresses in the cross-section at the ravine entrance, and (b) in the cross-section in the lower part of the ravine.

Bridge launching is a construction technique where the bridge framework is built in sections and pushed outwards from one or both abutments using a specialized tool (Zellner and Svensson, 1983). Controlling this process includes managing forces, deflections, and reactions at various stages of the launching process since their configuration during construction changes continually. During the bridge framework launching (Fig. 6), the balance between the framework walls can be disturbed by a catastrophic accident. The development of a real-time monitoring system is a potential approach to minimizing risks during the launching, as reported by Gale (2011), Kotpalliwar and Kushwaha (2024),