RESEARCH OF THE STRESS-STRAIN STATE OF PRECAST REINFORCED CONCRETE HOLLOW CORE SLABS UNDER THE ACTION OF A CONCENTRATED AND UNIFORMLY DISTRIBUTED LOAD

Abstract

The scientific work is devoted to a comprehensive study of the stress-strain state of prefabricated hollow-core floor slabs, establishing the nature of deformation, as well as determining the characteristics of crack resistance, deformability and load-bearing capacity experimentally under short-term loads. The experimental data obtained were confirmed by theoretical calculations. The scientific novelty of the experiments carried out within the framework of the presented work lies in the improvement of the principles of direct design of floor slabs from commercially produced beam slabs, the possibility of determining the stress-strain behavior of a slab structure using the formed ends. The method of monitoring the stressed behavior of a slab structure was also further developed. For the first time, the results of full-scale experimental studies of the stress-strain behavior of a prefabricated slab, carried out using the hydraulic loading method, have been obtained, and the features of the deformation of a slab embedded in the wall of a multi-story building have been experimentally established. The article provides recommendations for the practical use of the research results obtained, and also develops technical specifications for the production of concrete slabs during design and construction. The developed proposals were used in the construction of residential buildings in Kharkiv. When using the recommended grade of concrete C25/30 (instead of the actual grade C20/25 tested), the rigidity of the slab increases and its deflections will be smaller. Based on the data obtained from the experimental testing of the slabs, a generally positive test result should be stated. During further serial production of slabs, periodic testing of batches of slabs should be carried out in accordance with DSTU B V.2.6-53:2008. In this case, the slabs are accepted according to the indicators of strength, rigidity, crack resistance, fire resistance limits, frost resistance limits, as well as water resistance of slabs intended for use in aggressive environments. Keywords: concentrated load, testing, concrete, calculation, deflection, transverse force.