The National Transport University Bulletin

Abstract

The article is devoted to the assessment of the structural reliability of VTP-16 bridge beams with a span length of 16.76 m under adaptation to modern traffic loads of class AK-15. The study includes an analysis of the bearing capacity of the beams in their original condition, identification of compliance with the design standards of the period when they were constructed, and justification of the need for strengthening to 97 97 ensure operational reliability under current increased loads. Numerical modeling was carried out to evaluate different strengthening approaches, including reinforcement with conventional steel bars and external prestressed tendons. The obtained results demonstrate the efficiency of the proposed strengthening methods and confirm their applicability for extending the service life and safety of existing bridge structures. Objective – to assess the load-bearing capacity and structural reliability of VTP-16 bridge beams under AK-15 class loads, and to determine effective strengthening methods using conventional and prestressed reinforcement. Methodology – a 3D model of the beam was developed in the LIRA-SAPR software package, with calculations performed for load-bearing capacity according to the first group of limit states and for crack resistance according to the second group. The effectiveness of strengthening was evaluated by introducing additional conventional reinforcement and external prestressed reinforcement. Results – it was established that in their initial state, VTP-16 beams comply with the design norms of past years (H-30, NK-80), but do not provide sufficient load-bearing capacity under modern loads (AK-15, NK-100). Calculations showed that strengthening the beams with 32 mm diameter conventional reinforcement ensures normative strength, while the use of four 15.2 mm diameter prestressed strands provides increased load-bearing capacity, reduced deflections, and prevents cracking during operation. Conclusions – the study confirms the feasibility of strengthening VTP-16 bridge beams to adapt them to modern traffic loads. The use of prestressed reinforcement is the most effective method, ensuring the required levels of strength, stiffness, and crack resistance, thereby enhancing the reliability and durability of bridge structures

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