To the determination of the actual stress state of the elements of flat precast-monolithic slabs

Recently, a constructive system with the use of frame and frame-bced frameworks with precast reinforced concrete elements (flat precast-monolithic slabs) has been widely spread. The design of the frame uses monolithic or prefabricated columns and prefabricated monolithic flat slabs. A constructive solution is a flat floor slab consisting of precast hollow-core slabs adjacent in one level to monolithic bearing girders (conditional girders), using concrete dowels located in round cavities open at the plate ends and made monolithically with bearing girders. The work of the joints of the ends of the plates with bearing girders is of great interest. It appears that below in the above mentioned joints there are deformations of compression, as a result of the work of hollow-core slabs as the part of the floor slab for bending with an emphasis on bearing crossbars according to the hypothesis of flat sections that should affect the stressed state of the slab elements. It is established that the distribution of the main tensile and compressive stresses in the longitudinal central section of the multi-tensile plates clamping through the apertures in the linear and physically nonlinear problem, based on the performed studies, is not the same. In the linear and physically nonlinear formulation of the problem one can see that the distribution of the main compressive stresses is different by nature. Thus, in the case of a linear problem in the quarter of the slab, there is a zone of zero stresses, which is the boundary between the distribution of the main compressive stresses in the lower edge and the upper passage of the section of the element. In the nonlinear formulation of the problem, the zero-voltage zone is absent. Under the influence of the arched effect, the initial bending moment in the middle bores under the action of the distributed load is partially reduced.