By present time significant experimental and theoretical material on concrete creep has been accumulated. At the same time, the known approaches to calculation of concrete and reinforced concrete structures with regard to creep are oriented mainly to solving problems with relatively simple geometry of the product. Moreover, there are no mechanic-mathematical models of hereditary type oriented to the finite-element method.

The concept of modelling of long-term deformation of reinforced concrete structures in a three-dimensional statement, based on the use of the integral deformation modulus of concrete, does not allow one to carry out designing considering the technological prehistory. Therefore, the problem of developing a finite-element algorithm and corresponding software allowing the modelling of the volumetric stress-strain state of large-span prestressed reinforced concrete structures within the framework of the theory of hereditary aging is relevant.

The work of a reinforced concrete beam resting on an elastic foundation is considered. The strength characteristics of the beam materials - concrete and reinforcement - are considered as random normally distributed quantities. The parameters of the distribution of the probability density of the initial stiffness of the beam, the moment of crack resistance of the beam under the control of the strength of concrete in compression and tension are obtained. The beam base is considered as statistically inhomogeneous elastic half-plane with the soil elasticity modulus taken as a quasi-stationary random function of depth. The load on the beam, its geometric parameters and the modulus of elasticity of the foundation soil are taken as deterministic values. The parameters of the density distribution of the probability of bending moments in a reinforced concrete beam lying on a stochastic half-plane, and the probability of the formation of normal cracks in it, are obtained for the case of controlling the strength of concrete only in compression and for the case of controlling the strength of concrete both in compression and in tension.

In this study, a detailed analysis of the use of standardized deformation models is carried out to calculate the design characteristics of reinforced concrete elements, such as crack resistance. For theoretical verification of the values of the moment of cracking, calculation methods based on the use of a nonlinear deformation model are used.

A theoretical study of cracking moment using a non-linear deformation model shows that the application of a two-line diagram of concrete deformation allows to obtain the most accurate values of cracking moment.

The article is devoted to the research of application of reinforcing steel of a new spiral profile for reinforcement of reinforced concrete constructions. The article presents the results of experimental studies of prism specimens with screw four-row reinforcement with diameters of 20 and 32 mm of class Av600P and concrete of classes B30 and B60 under static compression loading. The purpose of the research was to justify the introduction into practice of the construction of an innovative screw reinforcement profile, which will develop the ideas and principles that have become the basis for the widely used six-row A500SP profile, whose design solution (the absence of longitudinal ribs with the arrangement of transverse protrusions in four rows with the possible formation of a two-start screw thread by them) makes it possible to significantly increase the rejection minimum value of the Röhm criterion (fR ≥ 0.075), which characterizes and determines the strength and deformability of the adhesion of reinforcement to concrete, which determine the strength and crack resistance of reinforced concrete structures, and, consequently, their operational safety and reliability. The coupling joints of screw reinforcement can significantly speed up the process of reinforcing work at the construction site as a result of replacing labor-intensive and expensive welded joints. The results of the research showed the effectiveness of application of new screw reinforcement of the Av600P class for reinforcing compressed reinforced concrete elements made of concrete of classes B30÷B60 with coupling threaded contact, partially contact and non-contact butt joints of the reinforcement.

Most of the experimental investigations devoted to the study of the stress-strain state of bent reinforced concrete elements reinforced with carbon fiber-based polymer-composite materials have examined only unloaded beams or beams without preliminary cracks. However, reinforcement of real load-bearing structures is most often performed under load and taking into account previously occurring defects. At the same time, there are a limited number of systematic studies of the effect of preload on the bearing capacity of reinforced concrete beams reinforced with carbon fiber. This article presents a methodology for assessing the effect of the stress-strain state level of reinforcement on the bearing capacity and other parameters of the sections of bent reinforced concrete elements reinforced with carbon fiber, taking into account the physical nonlinearity of concrete and using real deformation diagrams, including reinforcement and reinforcement systems. On the basis of the developed method, numerical studies of the operation of reinforced concrete sections reinforced at various stages of SSS were performed. After analyzing the obtained data, we can conclude that the level of reinforcement load has a significant effect on the deformability, rigidity and strength of normal sections of reinforced concrete beams and the need to take this factor into account when calculating bending reinforced concrete elements. After analyzing the data obtained, we can conclude that the influence of the reinforcement load level on the deformability, rigidity and strength of normal sections of reinforced concrete beams and the need to take this factor into account when calculating bending reinforced concrete elements.

Some examples of failures of structures, buildings, where the lack of robustness was recognized, are analyzed. Several author’s definitions for robustness are presented and discussed. Special emphasis is given to the fact that define robustness as an intrinsic structural property and the other hand it as a property of the structure and its environment. Some related concepts are presented and discussed.

The most important proposed measures for robustness are also present-ed including some illustration examples. Finally, a comparison between them is made and the respective shortcomings are identified. After anal-ysis of the robustness nature, a new structural oriented definition is pro-posed. Based on the highlighted shortcomings of the existing measures, in particular those related with the application to deteriorated structures, a conceptual framework for robustness assessment is proposed.

Currently, much attention is paid to the structural reliability and safety of buildings and structures, as well as the speed and quality of design and construction. The increase in these indicators is facilitated by the expansion of the use of information modelling technology through the integration of new calculation methods into the digital building model.

The paper considers the design of structures of a single-storey frame industrial building using information modeling technology. The order of work in the programs “Tekla Structures” and “Crystal” is presented on specific examples. Conclusions are given about the advantages of using BIM technologies in the construction industry.

The problem of restoring reinforced concrete structures that have received dynamic impacts (emergency as a result of collisions with vehicles, damage as a result of dismantling nearby structures, explosive impacts) is quite an urgent issue. The current regulatory documents regarding the restoration and reinforcement of reinforced concrete structures do not fully correspond to the issues related to the results of dynamic impacts that have characteristic features. Also, the volume of published scientific papers on this topic is not sufficient and implies the need for further research. Nevertheless, to date, a certain amount of work has been carried out to restore such structures with subsequent tests and confirmation of the required level of reliability. The article considers the experience of restoring reinforced concrete structures of bridge spans that were damaged as a result of dynamic impact from vehicles - the result.