STUDY OF SAMPLES OF PERMANENT POST-TENSION REINFORCED CONCRETE FORMWORK SLABS FOR BRIDGES DECK

Abstract

Shortening the terms of objects construction is one of the most important economic tasks in modern conditions. But it is worth considering the fact that fully prefabricated structures have a number of disadvantages that affect the further operation of the transport facility. Among them are problems related to the impossibility of ensuring reliable waterproofing of the prefabricated elements joints and as the result corrosion of concrete and reinforcement. Taking into account the experience of using prefabricated structures, domestic engineers, as well as foreign colleagues, came to the conclusion that monolithic and prefabricated-monolithic structures provide greater durability of the structure in general. That is why the use of prefabricated monolithic span structures in the construction of transport facilities has become widespread. The use of permanent formwork during the installation of a monolithic deck slab is a promising trend in modern bridge construction. This is especially relevant in the construction of overpasses and flyovers in dense urban areas, where the use of inventory scaffolding for slab concreting is impossible or significantly complicates existing traffic. Although permanent formwork has been used for many years, its work as а part of the structure has not been studied much. It is possible to cite many examples of use of permanent formwork both abroad and in domestic practice. Crack resistance is a pressing issue both individually of permanent formwork tiles and of the prefabricated monolithic in general. The article deals with formwork in the form of flat reinforced concrete slabs with pre-tension reinforcement. The production of such plates is quite economical, despite the use of prestressing, especially by the extrusion method, with subsequent cutting into segments of any shape and length. Study of the experience of using permanent formwork in different countries was the first stage of the research. In order to understand the expediency of using permanent formwork slabs, it is proposed to test samples of such slabs to determine their efficiency and suitability for further operation. The tests were carried out on a power bench with two concentrated forces using the "pure bending" method. The test results for such plates are also given in the article.