Features of the Work of Monolithic Flat Floor Slabs Under Construction

Abstract

The formwork for the construction of monolithic flat ceilings is traditionally carried out by installing supports in spans, in areas where the greatest deflections develop. The installation of temporary supports in the stage of erection changes the design scheme of the plates: zones of negative moments appear in the zone above the additional supports. When concrete reaches the ultimate tensile stresses in the upper zone, cracks appear that can significantly affect the strength and deformation properties of the structure in operation. This work is aimed at revealing the features of the work of plates in the manufacturing stage, their effect on the strength and deformability of the overlapping and the establishment of the optimal location of temporary formwork supports. The object of the study was a cell of a non-beam overlap, measuring 6×9m, the stress-strain state of which was analysed with the help of the Scad program for various arrangements of temporary supports. The plots of the dependence of the influence of the amount of reinforcement in the slab at the time of cracks formation are obtained, as well as the effect of the concrete transfer strength at the time of crack formation. According to the results of the research, the most acceptable options for installing temporary support elements are proposed, which cause the minimum values of negative moments. The results of the article can be used in practice in the construction of monolithic ceilings.