The technology of repairing reinforced concrete bridges typically involves closing traffic on one half of the structure and performing work on it when it is possible to move vehicles on the second part of this structure. The main process of interest to practitioners in terms of hardening concrete, which occurs in the beams of a span structure during the passage of a temporary moving load, is deformation. By the time the cement of freshly laid concrete of the overhead reinforcement slab is hardened, it is necessary to create the necessary conditions for this (temperature, humidity, immobility over time, etc.). Before concrete acquires strength, movements arising in the span structure cause the destruction of cement stone at the formation stage. It is necessary to investigate the presence of deformations, as well as their impact on the impossibility of forming a homogeneous structure of concrete and its adhesion to reinforcing elements that combine the existing slab with the new one. This study has established deformations induced by a temporary load from 1.61 to 5.83 mm, which have a negative impact on the process of solidification of concrete in the reinforcement slab for a span structure during the repair of a motorway bridge. The three-dimensional models were calculated by simulating a bridge of the M-04 highway. The results underlie the conclusions that the technology of repair work does not take into consideration the required conditions for high-quality concrete strength acquisition in an additional slab. The study results established that operations on concreting an additional overhead reinforcement slab in the presence of vibrational effects exerted by the temporary load on the span structure cannot be performed because of the destruction of concrete at the hardening stage. Given the above issue, several ways to address it have been devised and analyzed; the best of them is recommended

Purpose. The purpose of this work is to analyze the existing composite reinforced concrete girder structures of bridges, determine their advantages and disadvantages, study of stress changes in the elements of the girder structure and its deflections caused by the coupling of metal beams and reinforced concrete roadway, the possibility of using these structures in post-conflict reconstruction. Methodology. Examination of the data covered in the literature. Studying the experience of design and construction of reinforced concrete girder structures of bridges in our country and abroad. Construction of the calculation model, its loading, change of thickness of a reinforced concrete plate, the analysis of results. Findings. The result of this work is collected data on the advantages and disadvantages of reinforced concrete girder structures of bridges under the railway, the impact on stress in the elements of the girder structure and on its vertical deflections by the joint work of metal beams and concrete slab, analysis of the possibility of using such girders for fast resumption of train traffic. Originality. It lies in that for the rapid and high-quality restoration of destroyed transport infrastructure, including railways, it is proposed to use metal beams of long-term storage (mobilization reserve), which are made on standard projects in the middle of last century, combined with reinforced concrete slab included in joint work, thereby obtaining composite reinforced concrete girder structures. This will allow rational use of the available reserve of materials, high recovery rates and reliable recovery of train traffic. Practical value. Based on the obtained data, it is possible to conclude that the method of combining the long-term stored metal beams and reinforced concrete slabs of the carriageway increases the load-bearing capacity of the obtained girder structures, so the use of these structures can ensure the effective restoration of war-torn railway structures in a short time.