METHOD OF REINFORCEMENT OF REINFORCED CONCRETE BRIDGE SUPPORTS BY ARRANGEMENT OF BITRAPEZOIDAL CASINGS

The paper contains developed the method of reinforcement of reinforced concrete bridge supports by arrangement of reinforced concrete casing on the example of an emergency bridge structure located on the state road M-12 in the Gajsin town, Vinnitsa region. Have been proven that for the further long-term operation of bridge supports, in addition to the reinforcement device, it is also necessary to seal the expansion joints of the span structure located directly above the supports. Have been described the main components of intermediate bridge supports erected in Ukraine during the second half of the 20th century. Have been considered typical defects, which were occurred on the two-cantilever supports of bridge structures during long-term operation. Have been estimated the degree of danger of each of the defects. Have been proved the systemic nature of defects and damages of prefabricated reinforced concrete crossbars. Have been considered the  probable causes of defects at the bridge supports are considered, namely, destruction of bridges expansion joints. As a result, regular, long-term non-project soaking of supports; violation of the solidity of the concrete protective layer of the working reinforcement of the cantilever parts of the crossbars due its overload; destruction of the mixture from the seams of monolithic semi-crossbars due to its low strength; reinforcement corrosion; loss of frost resistance of concrete; increase in dynamic influences. Have been considered the design and typical defects of standard prefabricated concrete trusses, which are installed on bridge supports for direct perception of loads from the span structure. Have been considered the standard methods of strengthening bridge supports and trusses, their advantages and disadvantages. The paper focuses on the importance and necessity of restoring the tightness of expansion joints by using modern Maurer type constructions in conjunction with the installation of waterproof monolithic or overhead plates of reinforced span structures. Have been proposed an original form of clips for double-console bridge supports in the form of double-trapezoids which significantly improve their architectural expressiveness and optimize the structural scheme of supports. Have been proposed to use self-compressing concrete to save material costs and time during the construction of temporary special and auxiliary devices (formwork) for monolithic casing. Have been proposed an effective methodology and a rational technological sequence for performing work on strengthening. Have been summarized the practical experience of performing construction and installation works on monolithic supports with self-compacting concrete mixes according to the method proposed by the authors of the article which were made according to the technology of Sika. Have been summarized the experience of bridge operation after sealing expansion joints and overhaul of bridge supports.