The article presents the results of experimental tests of a number of reinforced concrete eccentrically compressed structures reinforced with composite materials in the longitudinal and transverse directions. During the study, it was found that the composite external reinforcement does not work the same in reinforced concrete structures, but depends on the area of ​​​​the composite materials on the structure. This is due to different stress concentrations along the length of reinforced concrete structures from the action of bending moments and transverse forces. The consequence of this uneven stress state in composite materials is their premature delamination and an underestimation of the overall efficiency of the reinforcement system. This article presents the results of experimental data on the values ​​​​of relative deformations εf of composite materials of reinforced concrete pillars, flexibility λh = 10, tested at a large eccentricity of load application (e0 = 4 cm or 0.32h), going beyond the core of the section. This paper considers various options for composite reinforcement located both in the longitudinal and transverse directions. The deformations were recorded by strain gauges with a 2.0 cm base, at all load levels. As a result, the maximum relative deformations of composite materials were recorded, the most effective zones of transverse clamps location and places where deformation along the fibers did not develop were identified, therefore, the composite in the reinforcement system did not work. The obtained data make it possible to develop the most rational reinforcement options.

Keywords: concrete, reinforced concrete, composite material, carbon fiber, external reinforcement, deformations, compressed elements

This article presents a new method of strengthening reinforced concrete columns using metal and composite materials. The analysis of existing traditional and modern methods of strengthening of reinforced concrete compressed elements has been carried out and their main disadvantages have been identified, taking into account which a new reinforcement method has been developed. This study presents the results of testing the effectiveness of a new reinforcement method, describes in detail the basic schemes, technology and procedure for performing reinforcement work. The results of the conducted experimental studies are presented. The strength of the control samples was compared with the reinforced ones. Proposals have been developed to strengthen reinforced concrete columns with metal elements arranged longitudinally and composite materials glued in the form of clamps with fibers arranged in the transverse direction.

Keywords: steel, reinforced concrete, heavy concrete, test, rack, composite material

This article presents a new developed calculation methodology, which includes provisions for standard calculations and takes into account the peculiarities of the operation of eccentrically compressed reinforced concrete structures operating at large eccentricities of load application. Adjustments have been made to the calculation methodology to take into account the following factors: the standard methodology uses the maximum tensile strength of reinforcement; proposals have been developed to determine the actual resistance of tensile reinforcement, which, in fact, will be significantly lower than the limit. Proposals are given that take into account the limiting deformations of concrete, which, in turn, will be a key quantity for determining the resistance of tensile reinforcement in the cross section. The article also presents the results of experimental studies of a flexible reinforced concrete pillar operating with a load eccentricity equal to e0 = 0.32h. Theoretical calculations and experimental studies were analyzed and appropriate conclusions were drawn.A formula has been developed to determine the real resistance of the stretched metal reinforcement at the time preceding destruction. The calculation algorithm has been compiled. When comparing theoretical and experimental strength, the difference did not exceed 5%.

Keywords: steel, heavy concrete, reinforced concrete, testing, stand

The issues of preserving existing green spaces and other elements of the natural landscape during new construction are considered. Methods for preserving perennial plantings throughout the entire course of construction are proposed. If it is impossible to save the tree at the construction site, a method of transplanting it to another place is proposed. It is proposed at the stage of design and survey work to identify healthy trees that do not grow on the site allocated for a building (structure) under construction. Then solve the problem of locating the object on the ground in such a way as to preserve healthy perennial trees as much as possible. To do this, it is necessary to carry out the removal of the object to the area, moving it as far as possible from healthy trees. The distance required to protect the tree from external influences during work is equal to the projection of the crown on the ground plus 1.5 m. At this distance, it is recommended to make stationary fences for each tree. A tree transplantation scheme and a method for calculating its weight for the selection of equipment for digging and transportation have been developed.

Keywords: landscaping, construction, tree, tree transplanting, asphalting