Wooden-concrete floors and the problem of joint work of wooden and reinforced concrete elements of structures

Abstract

EN: The connection of a concrete slab and wooden beams is veryimportant, therefore, the joint operation of the composite floor depends on the correct choice ofthe type of connection.Purpose of the study. When a concrete slab rests freely on a beam, then the frictionbetween the materials is considered insignificant, in this case, under load, the beam and the slabwill work separately, since slippage will occur between them. Slippage can be reduced byinstalling connectors between timber and concrete. In turn, the prevention of slipping inevitablyleads to a decrease in vertical movement. Thus, by connecting two elements together, theircombined bending stiffness can be increased. This phenomenon of thes two components working together is known as composite action. Of course, the degree of composite action increases with the stiffness of the joint. The degree of composite action may differ from composite action without bonding, full compositeaction for an infinitely rigid bond.The higher cross-section of the composite member compared to the cross-sections of itsindividual sub-members results in a longer internal moment. Consequently, the normal stresses resulting from an arbitrary external load are reduced within the structure. For a very rigid connection, the result is a state in which the concrete slab is mainly subjected to compressive forces, while the tensile stresses are concentrated in the timber part . Thus, the materials of the composite section are used as efficient as possible. It should be emphasized that the correlation between the flexural stiffness of a composite structure, often referred to as effective flexural stiffness, and the stiffness of a joint is not linear.