Research of geometrical problems of torse surfaces with cuspidal edge, the outset of which was put by G. Monge, are not stopped till present time. Much less of works were devoted to study of stress-strain state, stability, and to vibration of thin torse shells. Apparently, this is connected with absence of real projects of structures in the form of torses, with the exception of products in the form of developable helicoids and objects of garden architecture. The offered paper is devoted to the realization of the methodic of design of form of torse surface with two directrix plane curves given in advance. This surface is placed on the rectangular plan and has the straight generatrixes coinciding with two sides of this rectangular plan. Theoretical constructions were illustrated and visualized with the help computer graphics. Five torse surfaces with geometrical condition given in advance were constructed. Algebraical curves of the second order, superellipses, and biquadratic parabola were chosen as directrix curves. One can increase a list of used plane curves if curves can be defined in explicit, parametrical, or in vector form.

The strength and compliance of the joints of load-bearing structures in multistorey panel buildings is determined by different parameters and significantly affects the forces and stresses that occur in the elements of such structural system. Horizontal action on a structural system consisting of prefabricated wall panels, under certain conditions, can lead to a situation where torsional mode will prevail. The key conditions for the occurrence of torsion, which are noted in most studies on this topic, will be the horizontal and vertical asymmetry of the building and significant horizontal loads. In this experimental work, fragments of wall joints were tested under the action of shear and torsional loads. The fragments of reinforced concrete panels were joined using a metal butt joint during welding. A metal plate acted as a connecting element. According to the results of the experiment, the stress-strain state of full-scale fragments of panel buildings was obtained. The nature of the destruction, maximum shear and torsional loads have been established. Joint deformation diagrams are constructed for all test samples.

The end-plate connections are most often used as a connection of beam to column and between beams that perceive a moment. Taking into account the difference in the strength of the end plate and the strength of high-strength bolts, which will lead to three different types of failure mechanisms, it is necessary to study the strength and stiffness of such joints using the component method. The most important parameters in this method are the calculated width of the bearing elements for bending and the stiffness coefficient. Determining the ratio of the strength of the connection elements to the failure mechanism and calculating the stiffness coefficient calculated on the basis of the T-shaped element is an important task. For this reason, the objective of this paper is to develop a method for calculating the bending stiffness and strength of the end-plate connections joints under monotonic loads. The proposed calculation method is based on the component method, structural mechanics and strength of materials. Verification is performed on the basis of the experiments performed, for which practical dependencies between the moment and the angle of rotation can be obtained. The practical implementation of the proposed method is demonstrated by calculating the bearing capacity and rigidity of the sample of the experiments performed.
As results of the study, it is possible to highlight the method for calculating the rigidity of the end-plate connections of beam to column, the influence of the strength of different elements of such connections on the mechanism of destruction and a recommendation for designing connections under monotonous loads. Using the developed method, it is possible to accurately estimate the bearing capacity and rigidity of the connection, design a diagram of the relationship between the moment and the angle of rotation.

This paper examines the bond strength between reinforcement and concrete in reinforced concrete structures under combined effects of corrosion and high temperatures. The analysis employs analytical models and regulatory data to evaluate changes in the strength characteristics of reinforcement and concrete under elevated temperatures and corrosion damage. Thermal and corrosion effects influencing bond strength reduction, material strength degradation, and internal stresses due to differences in thermal expansion coefficients of steel and concrete were taken into account. Results indicate that under high temperatures and significant corrosion levels, bond strength between reinforcement and concrete decreases considerably. The presented models and calculation dependencies allow for a preliminary assessment of the reliability and fire resistance of reinforced concrete structures under corrosion conditions.

The diagrammatic calculation method is used in the calculation of reinforced concrete structures for the most accurate modeling of its stress-strain state. When calculating using this method, real diagrams of material deformation under load are used. The use of this method to calculate a reinforced concrete element in sections with mechanical connections of reinforcement necessitates experimental studies to clarify the features of the joint work of concrete with reinforcement in places where mechanical connections are installed. In particular, it is necessary to study the features of deformation of mechanical connections of reinforcement together with concrete during cyclic loading. These issues are discussed in the proposed article. The methods and results of experimental studies of the operation of rebar rolled products of class A500C and mechanical connections by conical threads in a free state and when working with high-strength concrete of class B60 are presented. Two loading modes have been studied – static stretching and multi-cycle stretching. The peculiarities of the operation of mechanical connections by threads under the specified loading conditions, taking into account the effect of adhesion to concrete, are revealed. The experimental research results obtained are the basis for the development of a diagrammatic calculation method for reinforced concrete structures in sections with mechanical reinforcement connections.

The article describes the algorithm for probabilistic analysis of reinforced concrete beams made of wood-cement composite for a target reliability level. The reliability index and no-failure probability are used as the indicators for required level of reliability. Experimental studies on woodcement composite beam behavior with steel reinforcement are performed. The presented approach allows to determine the most rational reinforcement based on economic factors and safety level of the object. On the basis of probabilistic algorithms, it is possible to assign tolerances on the dimensions of the beam cross-section and on the location (distance) of reinforcement, based on ensuring the required level of nofailure probability. Reinforced wood-cement composite beam structures can be used as load-bearing and self-supporting lintels, having higher vapor permeability and energy efficiency than heavy concrete lintels. The permissible level of failure probability can be assigned for a group of elements of the objects individually, based on the criterion of acceptable risk.

The scientifically based assignment of target values of reliability measures is the first and one of the most important steps, both when calibrating the system of partial coefficients included in modern prescriptive standards for the design of structures, and when performing limit state checks based on direct probabilistic calculations and risk calculations within the framework of a new design paradigm based on the performance-based output result or a response.
In the research, threshold values of failure probabilities and corresponding reliability indices, obtained on the basis of the basic requirement for ensuring life safety, are used as minimum acceptable reliability measures. This approach is implemented using the LQI- criterion, when calculating the constant of the relative cost of saving lives, for the socio-economic conditions of the Republic of Belarus. The threshold values of the decision-making parameters obtained from the conditions for ensuring the safety of life determine the boundary of the area in which the economic optimization of reliability measures should be performed.
The target values of reliability parameters used in survivability checks in special design situations for the socio-economic conditions of the Republic of Belarus have been established, which makes it possible to reasonably calibrate the global safety coefficient when performing a nonlinear analysis of damaged structural systems. From a comparison of the main indicators of socio-economic development, it can be concluded that the reliability measures obtained are applicable, with minor adjustments, to the conditions of the Russian Federation.

To consider the problem of preservation and use of cultural heritage - ancient horse breeding complexes of the Belovodsk group. On the basis of archival documents and research carried out on the spot, in order to study the objects of the Belovodsk district of the Lugansk People's Republic, it is necessary to identify the lost objects with the identification of their possible location. To present the characteristics of the surviving objects of the complexes, including historical reference, a scheme of the master plan and measurements of the main structures of the complex.
The need to establish the most effective approach to solving the problems of the formation of horse-breeding complexes as one of the complexly organized elements of the artificial environment, forming a single structure of the functional-planning and transport frameworks of the regional historical and cultural environment, is revealed. The need to revise the models and methods of management of horse-breeding enterprises, the concept of their development has been established. The development of a fundamentally new direction will contribute to a new round of development of a number of cultural sites in the region and attract tourists.

Formulations of metal corrosion converters for modern construction based on orthophosphoric acid with the inclusion of surfactants is developed. Their feature is the use of Lewis acid solution as a functional additive, which allows you to quickly (5 minutes) treat the metal surface. The hydrogen indicators of the resulting systems have been studied. The effect of low temperatures on the pH of the studied solutions and the speed of metal surface treatment after their exposure at -18 and -2 °C were evaluated. At -29°C, crystallization of all compositions is observed. It was also found that the developed compositions of metal corrosion transducers retain their physical and mechanical properties even after long-term freezing (90 days). The proposed compositions are recommended to be used in the winter season (at temperatures below -10°C) only in the presence of greenhouses or internal heating.

Requirements for concrete used in the manufacture of structures operating in harsh operating conditions are different from those for concrete used in industrial and civil construction. Such special requirements are primarily due to difficult operating conditions, in particular for tunnel structures. Under the influence of a whole range of aggressive environmental factors, this type of structure is partially or completely destroyed, which in turn reduces their design service life. Therefore, a necessary condition for increasing their durability is the creation of a modified dense concrete structure with improved hydrophysical properties: low rates of water absorption, capillary suction, water resistance and high frost resistance. Currently, there are developments in strengthening and protecting such structures with materials with an increased degree of resistance to aggressive factors, for example, polymer compositions. However, polymer concretes have not found wide distribution due to their scarcity and high cost, so today the main building material in the construction of tunnel structures remains concrete and reinforced concrete. Thus, obtaining heavy concretes operating in harsh conditions with increased performance properties by modifying its structure is an urgent task. Objective: To establish the positive effect of complex modification together with a micro-reinforcing component on the hydrophysical properties of heavy concrete. Object: heavy concrete with a complex modifier (superplasticizer + polymer + metakaolin), reinforced with wollastonite for tunnel structures. Research results: A positive effect of complex modification on the properties of heavy concrete was established by reducing the content of binder (cement) and replacing it with metakaolin, which allows improving the hydrophysical characteristics: water absorption - 1.8%; water resistance grade - W14, with a sufficient margin of safety and frost resistance (F more than 600 cycles), which makes it possible to use this composition in practice to obtain building structures with specified characteristics operating under high loads and an aggressive environment, in particular, for tunnel structures.