Geometric nonlinearity shallow shells on a square and rectangular plan with constant and variable thickness are considered. Loss of stability of a structure due to a decrease in the rigidity of one of the support (transition from fixed support to hinged support) is considered. The Bubnov-Galerkin method is used to solve differential equations of shallow geometrically nonlinear shells. The Vlasov's beam functions are used for approximating. The use of dimensionless quantities makes it possible to repeat the calculations and obtain similar dependences. The graphs are given that make it possible to assess the reduction in the critical load in the shell at each stage of reducing the rigidity of the support and to predict the further behavior of the structure. Regularities of changes in internal forces for various types of structure support are shown. Conclusions are made about the necessary design solutions to prevent the progressive collapse of the shell due to a decrease in the rigidity of one of the supports.

The article offers a method and program for experimental studies of reinforced concrete structures with cross-shaped spatial crack under torsion with bending, the main purpose of which is to check the design assumptions and experimental determination of the design parameters of the proposed calculation method. The conducted experimental studies provide an opportunity to test the proposed calculation apparatus and clarify the regularities for determining deflections, angles of rotation of extreme sections, and stresses in the compressed zone of concrete. For analysis, the article presents a typical experimental scheme for the formation and development of cracks in the form of a sweep, as well as characteristic graphs of the dependence of the angles of rotation of end sections.

At the present stage of development, the diagram method for calculating rod elements made of reinforced concrete has a number of disadvantages, which is due to the lack of a single holistic theory. The paper attempts to lay its foundations. For this purpose, the most General structure of the theory is developed, and a three-level computational model is proposed, hierarchically built on the principle of discretization of the computational scheme: level 1 - "element" - design model of the rod, built according to the well-known rules of construction mechanics; level 2 - "cross" - enhanced non-linear (discrete) deformation model, adopted by SP 63.13330 with some significant clarification of the author; level 3 - material - analysis model of standard samples of concrete and rebar subject to action of the axial compressive or tensile static short-term load or under static short-time load, pure shear (to describe proposed Jenny more deformation curve of concrete). A detailed algorithm for the relationship of models at all three levels is described.

The current study considers a multifunctional high security residential complex. The study was conducted as part of the scientific and technical support for the design of the construction project. The compliance of design and survey documentation with the established requirements is usually a result of scientific and technical support of design. The methodology of determining wind loans and impacts is implemented with the help of a software package named SOFiSTiK. This software is capable of performing computations of stationary and non-stationary wind loans. Aerodynamic coefficients of drag and lateral force, as well as average pressure values were found as a result of applying the methodology in question. Also, patterns of medium pressure propagation on the surface of facade systems and patterns of medium-velocity fields of the complex were determined.

The article describes a method for reliability (probability of non-failure) analysis of structural elements based on p-boxes. An algorithm for constructing two p-blocks is shown. First p-box is used in the absence of information about the probability distribution shape of a random variable. Second p-box is used for a certain probability distribution function but with inaccurate (interval) function parameters. The algorithm for reliability analysis is presented on a numerical example of the reliability analysis for a flexural wooden beam by wood strength criterion. The result of the reliability analysis is an interval of the non-failure probability boundaries. Recommendations are given for narrowing the reliability boundaries which can reduce epistemic uncertainty. On the basis of the proposed approach, particular methods for reliability analysis for any structural elements can be developed. Design equations are given for a comprehensive assessment of the structural element reliability as a system taking into account all the criteria of limit states.

Most of Russian research about composite structure fire resistance are dedicated to the composite slab behavior. The composite beams fire resistance had been never investigated in enough volume: the temperature evaluation within the scope of the actual Russian design codes leads to the significant reduction in the shear connection strength. Meanwhile, there no correlation between the strength decreasing and type of the shear connection. The article provides an overview of the relevant researches and offers some approaches which could take into account bearing capacity reduction of the shear connectors within composite structures design.

The work of a beam with partial limitation of displacements on supports under conditions of unsteady high-temperature heating up to destruction is shown. Depending on the level of limitation of the rotational stiffness, the sequence of the formation of plastic hinges on the supports and in the span was revealed, which affects the resistance time of the beam. The conditions are formulated under which restrictions on the displacement of supports lead to the formation of adaptive resistance mechanisms. The time during which the beam resists bending and the ultimate resistance time depend on the combination of the stiffness level of the axial ka and rotational kr of the anchors. An increase in the level of limitation of the rotational stiffness kr in most cases leads to an increase in both the time of resistance to bending of the beam and the limiting time of resistance. With the provision of structural measures for the stiffness levels of the support fastenings ka and kr within certain limits, it is possible to significantly increase the fire resistance of the beam due to the formation of adaptive resistance mechanisms.

The article provides a classification of types of steel structure defects that occur during operation. The designs of one of the typical billboard projects for which verification calculations are performed are described in detail. The results of an engineering survey of the supporting steel structures of billboards in Moscow commissioned in 2016-2018 are presented. An analysis of the survey data revealed the most significant defects that arise during the operation of billboards: deviation of the structure from the vertical design position; lack of fastening bolts in the nodes. In the course of the calculations, the stress-strain state of the structures was assessed, adverse load combinations and the most loaded nodes were determined. For these nodes, a series of calculations was performed, in accordance with SP 43.13330.2012, to determine the bearing capacity of the structure depending on the number and area of bolts. As a result, a summary table of the required areas is obtained, which clearly shows the minimum required number of bolts in the design and inclined position of the structure.

The environmental protection is not only an important social problem, but also an efficiency increasing factor of construction operations. This article describes the practical effect of air pollution during the construction site of buildings, which are situated in Rostov-on-Don. Nowadays the limitation of air pollution emissions from construction operations is regulated by a number of normative documents, but civil designers, unfortunately, do not always meet the regulation of emissions in full obedience in the construction operating for a number of reasons. The correct environmental impact assessment from construction is possible, taking into account the sequence and simultaneity of the operations. It is especially important for the construction taken place on the territory of cities. According to the study, a set of measures for air pollution reduction was developed. Such measures can reduce the air pollution by 1.5-2 times.

N order to contribute to the sustainability of the brick construction sector, this work studied the formation of economic and environment friendly sandy clay brick. Therefore, the goal was set to be developed, a “sandy clay brick with cement mix”, which has more structural durability, less weight, low cost, together with high performance with respect to indoor air quality. In this research, variation on soil - cement brick with gradual increase in cement content replacing soil material and how the soil- cement brick may be studied using soil and cement as binder by fulfilling the requirement of National Building Code (NBC). The water cement ratio was kept controlled and all other material properties used were same. The effect was seen on compressive strength because the 28 days strength of brick is slightly more when soil is replaced by 15% cement content then no replacement of soil by cement strength. Taking about 11 samples starting from 0 % to 50 % cement content it was found that sandy clay soil - cement brick with compressive strength up to 23.44 MPa with traditional value may be achieved.