COMPRESSED ELEMENTS WITH A VARIABLE IN LENGTH STIFFNESS EQUILIBRIUM FORM STABILITY DETERMINATION

One of the most powerful modern methods of calculating complex building structures is the finite element method in theform of a displacement method for discrete systems, which involves the creation of a finite element model, that is, splittingthe structure into separate elements within each of which the functions of displacements and stresses are known. On the basisof the displacement method and the methods of iterations and half-division, an algorithm for stability calculation of the firstkind equilibrium form of compressed reinforced concrete columns with hinged fixing at the ends, considering the stiffnesschanging has been developed. The use of the above methods enables to determine the minimum critical load or stress at thefirst bifurcation and their stability loss corresponding form. The use of matrix forms contributes to simplification of high order stability loss equation. This approach enables to obtain the form of stability loss that corresponds to the critical load.

IMPROVING WATERPROOFING PROPERTIES IN THE WALL BASEMENT AREA BY INJECTION METHOD

The article is focused on the natural experimental research of injection waterproofing impact on basement areas of existingbuildings brick walls. Two types of experimental installations for waterproofing material injection have been developed. Thesecond type turned out to be more efficient due to the fact that it could cover larger waterproofing wall area. It can possiblyspeed up the process of walls waterproofing and major repairs of buildings in general. According to the experimental data, after the injection waterproofing placement, the wall moisture content decreased by half due to the high quality waterproofingmaterial and performed installation work.

METHOD OF FORECASTING THE TERMS OF SETTLING OF STRUCTURES ON SOILS WITH SILT LAYERS

The method of forecasting the size and timing of sedimentation of structures on soils with silt layers, based on the results offield observations, has been developed. It is suggested to use a set of exponential dependencies with a constant component.The algorithm and software for calculation of the envelope by experimental data by a stepwise approximation are developed.The process of consolidation of soils is considered as a combination of simultaneous and independent flow of phases of primary filtration consolidation and secondary consolidation of creep. According to the results of data processing of observations by direct iterative calculations by finding the minimum nonconnectedness by the method of least squares.

METHODOLOGICAL ASPECTS OF ASSESSING THE STEEL FRAMES RELIABILITY

The peculiarities of biogas technology application in the falling leaves utilization plants are analyzed and the application ofsoil cement is proposed to create the basic elements of such plants. A new schematic and constructive solution of biogasfermenter (bioreactor) with application of soil-cement technology with a blending method for efficient functioning oftechnological chain of biogas fermentation of fallen leaves and other plant residues for energy supply systems has beendeveloped. The possibility of reliable isolation of the space of the bioreactor to the excavation of the pit from the surroundingarray with soil cement screen is substantiated. The corrosion resistance of the soil cement waterproof screen has been proved.

DESIGN OF COMPOSITE SKIN PANEL FOR ROOF IN ACCORDANCE WITH THE REQUIREMENTS OF EN 1995-1-1 AND GSN В.1.2-2:2006

In the article design of composite (timber and plywood) skin panel has been considered according European and nationalstandards. The panel consists of timber webs and plywood skin. The design parameters are depth of webs and distance between webs within the defined skin parameters. In design the method of fictitious cross-section is applied. Check of the ultimate limit states is conducted in accordance with EN 1995-1-1 (ДБН В.2.6-161:2017). Loads to the panel are determined according to ДБН В.1.2.-2:2006. The usage of European and national standards complies with the actual requirements andwiden methodological base.

EXPERIMANTAL RESEARCHES OF THE CURRENT BURDENING COURSE PLATES ACHIEVEMENTS

The article presents the experimental study results of flat intercolumn plates loading work peculiarities of the beamless overlapping developed system. The attention is paid to the design of the experimental designs of the bearing structure with thebevelled platforms of suspension on the outer perimeter of the span plates. The technique of performing experimental studiesis presented. The conducted researches enabled to establish the nature of deformation and destruction of intercolumn plates asa separate element in the developed system of beamless overlapping. In this case, the magnitude of the compression deformations decreases to the point where the test specimens rest on the supporting blocks. It confirms the assumption of the transferof load from the spacers to the intercolumnar on the principle of "linear hinge". Attention is paid to the fact that the achievement of the bearing capacity is not accompanied by the process of destruction, but is characterized by significant movementsof the flying part of the plate in the vertical plane.

THE EXPERIMENTAL RESEARCHES OF REINFORCED CONCRETE I-BEAM ELEMENTS WITH NORMAL CRACKS WHEN TURNING

The data of experimental researches of the rigidity of reinforced concrete I-beam elements with normal cracks at the action on them of the twisting moment have resulted in this paper. It is shown that the dependence "torque-twist angle" is almost linear. Significant nonlinear deformations appear in the last stages of loading before failure. Therefore at normative torques, it is recommended to consider the work of reinforced concrete elements of the I-beam cross-section with normal cracks linear. It is shown that the presence of longitudinal reinforcement affects the strength and rigidity of beams with normal cracks. Quite a large part of the external torque is perceived by the pin forces in the longitudinal reinforcement. The difference between the external torque and the moment of the pin forces in the armature is perceived by the upper shelf of the I-beam element. In the absence of longitudinal reinforcement, the upper shelf can collapse at loads much smaller than the destructive load of beams with longitudinal reinforcement.

THE OWN STRESSES INFLUENCE ON SCALE EFFECT IN CONCRETE

The experimental technique and the experiment results on the influence of own stresses unevenly distributed over crosssection on materials strength and on scale effect are presented. The reasons for the occurrence and distribution of suchinfluence are analyzed. Based on the experiments results on fragile duralumin samples, the inevitability of influencing onscale effect in concrete during compression stresses, which are caused by unevenly shrinkage over cross section was proved.Possible reasons for the different (sometimes opposing) results of experimental studies of various authors on scale effect inconcrete in compression are explained. The influence of own stresses unevenly distributed over cross section on scale effectin concrete during compression, depending on samples size and concrete age, is analyzed in detail

SCIENTIFIC SCHOOL «RELIABILITY OF BUILDING STRUCTURES»: NEW RESULTS AND PRESPECTIVES

The article presents the results obtained by scientific school «Reliability of building structures» for the spice of five years2015 – 2019. Some aspects of the general approach to structural reliability assessment have been developed. Currentnormative calculations of structures were combined with the assessment of their reliability. Engineering methods were developed that allow to take into account an increase snow loading on coverage of building of variable height, to estimate theprocesses of snow thawing on roofs of the heated buildings and snow laying on cold roofs. It were investigated the specificwind load in the mountainous Carpathian region and loads of travelling cranes of different producers. Reliability of steelstructures of trunk pipelines and reinforced concrete beams with carbon-fiber reinforcement has been evaluated. Workfeatures of sheet steel structures were investigated. Construction accidents have been analyzed

INCREASE IN FLUID EXTRACTION, WHICH IS AT THE FINAL STAGE OF DEVELOPMENT DUE TO THE IMPROVEMENT OF EQUIPMENT INTENSIFICATION

It has been established that the fluid reserves, which are at the final stage of development, are difficult to extractable andwatered. The methods of intensification are analyzed and it is established that it will be rational in this case to pump carbondioxide into the reservoir. Its influence on a bundle of oil and water is determined. The results of the statistical processing ofthe change of the debit before and after injection of carbon dioxide, the influence of the volume of gas injected into the wellfrom the seperate permeability of the reservoir, as well as the expected rate of wellbore after injection, are presented.