To the multi-hollow reinforced concrete floor panels’ calculation according to the two groups of the limit states

Abstract

It is known that multi-hollow panels for simplification in the calculations are presented in the form of I-beams (T-shaped) beams and are considered according to the beam theory. The material for such structures is reinforced concrete - a composite material that combines the mutual work of concrete and steel reinforcement. The purpose of this work is to study how the cross-sectional representation shape of the multi-hollow panels made of the reinforced concrete structural material affects the samples of various lengths, by establishing the action of the above factors (the way the cross-section and length are represented) on the bearing and deformation ability, as well as the cracking load. We examined the various length panels’ samples, freely supported and working on bending, with a cross section in a natural form, in comparison with the similar length I-beam samples. The load was sequentially applied to the samples in increments of 1 kN, until the yield strength of the reinforcement in the stretched zone was reached. A numerical study of multi-hollow panels was carried out, taking into account the physical nonlinearity of reinforced concrete, with the formation of a plastic hinge in the middle of the span. The load-deflection graphs are obtained when modeling the corresponding lengths of the samples with a natural and I-section shape. It was found that the length of the panel affects the calculation results of the shapes under consideration, and the shorter the length, the more obvious the deviation in the load-deflection graphs. The correction factors to refine the calculations of reinforced concrete slabs for cracking, deformation and breaking loads are proposed.