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A method has been proposed to calculate the composite timber-concrete bending elements taking into consideration the non-linear work of a nail joint and the stretched reinforcement in a slab. An acting building code regulates the structure estimation based on the linear-elastic work while the pattern of the joint's deformation under loading demonstrates a pronounced non-linear character. Estimation formulae do not account for the presence of reinforcement in a concrete slab, which leads to the irrational use of the structure's load-bearing properties. A dependence has been proposed to determine the slip modulus. The determining coefficients are computed based on the rated characteristics given in the acting design standards. An algorithm for calculating the composite timber-concrete bending structures has been given, taking into consideration the deformation diagram of the joint and reinforcement in the stretched zone of a concrete element. It has been established that the normal stresses for the considered variants of timber-concrete beams, determined on the basis of the proposed procedure and the linear-elastic model, differ by 1-8 %. At loads corresponding to plastic deformations, those stresses that were estimated in line with the linear-elastic model prove to be understated. At loads exceeding 0.75 kN/m for the beam with a span of 3 m, and 0.5 kN/m for the beam with a span of 5 m, stresses in the stretched region of a concrete slab exceed the concrete stretching strength while the stresses in a timber beam do not reach the ultimate values. In fact, in this case, the structure's load-bearing capacity is underutilized because the stretching effort in the cross-section with a crack is accepted by the reinforcement. Based on the design features of timber-concrete floors (the thickness of a slab and protective layer), an analysis of the load-bearing capacity considering the reinforcement has been performed. It has been established that the load-bearing capacity of a slab ensures that an estimated bending momentum is tolerated up until the loads that cause the destruction of the timber beam. At the same time, the conditions for the rational operation of compressed concrete and stretched reinforcement are met

Since layers are components of a three-dimensional structure, the very process of cutting layers can directly affect the surface finish and mechanical properties of the structure, which are the two main disadvantages of FDM. In this regard, the study of different slicing algorithms can deepen the understanding of problems and gaps in FDM, which will help improve the quality of 3D printed building objects. Cutting algorithms developed for FDM technology are divided into two main groups: planar and non-planar. Complex algorithmic calculations are required to enable the printer to deploy multi-axis plane and non-plane, which is a drawback of these advanced methods. The article discusses the basic principles of slicing and conditionally outlines the possible difficulties that arise during the implementation of FDM technology, and also describes in detail the structure of the STL format file in binary and ASCII (English American standard code for information interchange) formats. The general characteristics and limitations of the STL file format were studied. The description of methods of classic slicing of the model and the mechanisms of implementation of more specific tasks are given. Current challenges and promising solutions to the problem are presented.

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3* Кафедра залізобетонних та кам'яних конструкцій, Державний вищий навчальний заклад «Придніпровська державна академія будівництва та архітектури», вул.