Introduction. Metal reinforcement A-IIIв, manufactured from reinforcement A-III in accordance with GOST 5781 by pulling, was quite widely used for slabs of span structures of bridges in the period before 1991, as well as later. There is a need to repair such structures due to the exhaustion of their resource due to a significant duration of operation, damage due to the impact of means of destruction during hostilities. Often, the best option for repairing such spans is to replace a separate plate or plates with similar ones, since in this case there are no problems with the size of height, resting on existing supports, etc.
Problem Statement. The vast majority of bridges in Ukraine, built in the period 1960-1991 and, to a large extent, in subsequent years, were designed according to typical projects. A large number of these bridges were built from girder slabs according to typical designs, where class A-IIIв reinforcement was used as prestressed reinforcement. These reinforcements were produced directly at the factories producing slabs structures from reinforcements of class A-III in accordance with GOST 5781 by pulling. To perform such works, the manufacturing plant must have appropriate equipment, qualified specialists, documentation, and obtain reinforcements of the required quality. As for the documentation, in the period up to 1991, such documentation was developed centrally and distributed to factories manufacturing structures. After 1991, this does not happen, the documentation is often not updated, which can be the reason for not ensuring the quality of the structures.
Purpose. To analyze the documentation for the manufacture and use of reinforcement A-IIIв for the manufacture of slabs of span structures of bridges with a length of 12 m in accordance with the documentation VTP 21-86 (addition).
To research the reinforcement A-IIIв, which is manufactured in accordance with the documentation YN 218 USSR – 026-84 directly at the manufacturing plant from the reinforcement of class A-III in accordance with GOST 5781 by pulling it for further use for the manufacture of slabs of span structures of bridges with a length of 12 m in accordance with documentation VTP 21‑86 (addition). Establish the possibility of using reinforcement A-IIIв in today’s conditions for the manufacture of slabs of span structures 12 m long in accordance with the documentation VTP 21-86 (addition) for the repair and construction of bridges.
Materials and methods. The methodology for the manufacture of armatures A-IIIв was studied. Experimental studies of the characteristics of reinforcement A-III in accordance with GOST 5781 were carried out, in particular, geometric dimensions, yield strength, temporary resistance, relative elongation after rupture. Yield strength, temporary resistance, relative elongation after rupture reinforcement A-IIIв, which was manufactured in accordance with the methodology given in YN 218 USSR – 026-84 from reinforcement of class A-III in accordance with GOST 5781 by pulling, were carried out.
Results. Input control of A-III class reinforcement in accordance with GOST 5781 and preparation of reinforcing elements was carried out. According to the results of determining the geometric dimensions, determining the quality of the surface, and the results of tests on axial tension of samples of reinforcement Ø 20 mm of class A-III according to GOST 5781, it was established that the selected samples meet the requirements of GOST 5781. All technological operations related to the reinforcement of reinforcement A-III by pulling were carried out in accordance with the documentation YN 218 USSR – 026-84.
According to the results of tests for axial tension of samples of armature Ø 20 mm of class A‑IIIv, which were manufactured in accordance with the documentation YN 218 USSR – 026-84, it was established that the selected samples meet the requirements of YN 218 USSR – 026-84. The yield strength of reinforcement A-IIIв exceeds the yield strength of reinforcement A-III within the required limits.
Conclusions. It was established that the reinforcing bars of reinforcement A-IIIв manufactured during the research are suitable for reinforcing the plates of bridge spans 12 m long in accordance with VTP 21-86 (supplement). For the further use of reinforcement A-IIIв in today’s conditions for the manufacture of slabs of girder structures 12 m long in accordance with VTP 21-86 (addition) for the repair and construction of bridges, it is necessary to develop technological documentation that would take into account current regulatory documents. It must be taken into account that DSTU 9130 entered into force with the cancellation of GOST 5781 in Ukraine. Therefore, it is necessary to conduct further research on reinforcement in accordance with DSTU 9130, in particular, regarding the possibility of manufacturing from it reinforcement strengthened by pulling.
