Subject: one of the promising trends in the development of structural mechanics is the development of methods for solving problems in the theory of elasticity for bodies with continuous inhomogeneity of any deformation characteristics: these methods make it possible to use the strength of the material most fully. In this paper, we consider the two-dimensional problem for the case when a vertical, locally distributed load acts on the hemisphere and the inhomogeneity is caused by the influence of the temperature field. Research objectives: derive governing system of equations in spherical coordinates for determination of the stress state of the radially inhomogeneous hemispherical shell under locally distributed vertical load. Materials and methods: as a mechanical model, we chose a thick-walled reinforced concrete shell (hemisphere) with inner and outer radii a and b, respectively, b > a. The shell’s parameters are a = 3.3 m, b = 4.5 m, Poisson’s ratio ν = 0.16; the load parameters are f = 10MPa - vertical localized load distributed over the outer face, θ0 = 30°, temperature on the internal surface of the shell Ta = 500 °C, temperature on the external surface of the shell Tb = 0 °C. The resulting boundary-value problem (a system of differential equations with variable coefficients) is solved using the Maple software package. Results: maximal compressive stresses σr with allowance for material inhomogeneity are reduced by 10 % compared with the case when the inhomogeneity is ignored. But it is not so important compared with a 3-fold decrease in the tensile stress σθ on the inner surface and a 2-fold reduction in the tensile stress σθ on the outer surface of the hemisphere as concretes generally have a tensile strength substantially smaller than the compressive strength. Conclusions: the method presented in this article makes it possible to reduce the deformation characteristics of the material, i.e. it leads to a reduction in stresses, which allows us to reduce the thickness of the reinforced concrete shell, and also more rationally distribute the reinforcement across the cross-section, increase the maximum values of the mechanical loads.

The article describes the problem of stability of elastic orthotropic rectangular plates for the case when two opposite sides are simply supported, and two other sides have boundary with either simple supports or fixed supports, which are arbitrarily combined. The plate that is simply supported all over the contour is not considered in the article since the authors described it in the earlier publication. The external load is uniformly distributed along the side and is applied to the shorter side of the plate. To solve the stability problem, the authors use an approximate analytical method - the form factor interpolation method, which is based on the functional relationship between an integral geometric parameter of the mid-plane surface (the form factor) and an integral mechanical parameter (the critical force of buckling). Subject: stability of elastic orthotropic rectangular plates for the case when two opposite sides are simply supported and two other sides have combination of simple supports and fixed supports arbitrarily combined. Materials and methods: the form factor interpolation method (FFIM) is used to solve the stability problem of elastic orthotropic rectangular plates. The solutions which were obtained by the FFIM method were compared with the results of calculations by FEM (the program SCAD Office 11.5). Results: for orthotropic rectangular plates with combined boundary conditions, we obtained analytical expressions for critical force surfaces and they depend on an integral geometric parameter - form factor and flexural stiffness ratio. To the authors’ knowledge, these expressions are obtained for the first time. The critical force surface for orthotropic rectangular plates constitutes one of the boundaries of this integral physicomechanical parameter for the entire set of orthotropic plates with arbitrary convex contour. Therefore, this surface can be used for obtaining reference solutions by the form factor interpolation method. We demonstrated how to obtain the solution of the stability problem for orthotropic rectangular plates by the form factor interpolation method using the results obtained from the aforementioned analytical expressions as the reference solutions. The solutions obtained by the form factor interpolation method are compared with the results of calculations by the finite element method and show a good accuracy. Conclusions: the analytical expressions for critical loads presented in this work can be used directly for the stability analysis of orthotropic rectangular plates loaded in one direction as well as to obtain one of the reference solutions by the form factor interpolation method for plates with arbitrary convex contour and combined boundary conditions. The proposed approach can be extended to other forms of plates, boundary conditions and loading types.

Tower cranes are one of the main tools for execution of reloading works during construction. Design of tower cranes is carried out in accordance with RD 22-166-86 “Construction of tower cranes. Rules of analysis”, according to which to ensure stability it is required not to exceed the overturning moment upper limit. The calculation of these moments is carried out with the use of empirical coefficients and quite time-consuming. Moreover, normative methodology only considers the static position of the crane and does not take into account the presence of dynamic transients due to crane functioning (lifting and swinging of the load, boom turning) and the presence of the dynamic external load (e.g. from wind for different orientations of the crane). This paper proposes a method of determining the stability coefficient of the crane based on acting reaction forces at the support points - the points of contact of wheels with the crane rail track, which allows us, at the design stage, to investigate stability of tower crane under variable external loads and operating conditions. Subject: the safety of tower cranes operation with regard to compliance with regulatory requirements of ensuring their stability both at the design stage and at the operational stage. Research objectives: increasing the safety of operation of tower cranes on the basis of improving methodology of their design to ensure static and dynamic stability. Materials and methods: analysis and synthesis of the regulatory framework and modern research works on provision of safe operation of tower cranes, the method of numerical simulation. Results: we proposed the formula for analysis of stability of tower cranes using the resulting reaction forces at the supports of the crane at the point of contact of the wheel with the rail track.

Research objective: assessment of the impact of crane loading on safe operation of building by using probabilistic methods; taking into account accumulation of damage in building’s structural elements occurring during operation period. Materials and methods: current computational schemes exploit procedures that do not take into consideration all external effects and changes in structures occurring during operation period of an industrial building. They do not provide algorithms for assessment of spatial response of building’s structures if probabilistic methods are used. Results: the experimental and theoretical research carried out by the author resulted in more precise definitions for computational models and for computational methods of analysis of industrial buildings under the action of various crane loads, including those that are not considered by regulatory documents. The suggested models and methods will enable us to design bearing structures of frameworks in accordance with their real operating conditions. The data obtained in a number of full-scale experiments lead to the conclusion that the amplitudes of vibrations caused by lateral forces when the overhead crane travels with a skew are significantly larger than the amplitudes observed during deceleration of the crane trolley. Conclusions: a hybrid algorithm has been developed; the suggested algorithm implements a complex of procedures for assessment of changes occurring in frame structures under different loading scenarios, during the service life of an industrial building.

Subject: the principles of shape formation of pile foundations with broadening. The research direction on shape formation of pile foundations in difficult engineering-geological conditions was not properly developed due to its complexity and uncertainty. Research objectives: the formation of a new conceptual-system approach in the theory of shape formation of structures of pile foundations with broadening. Materials and methods: experimental methods, numerical simulation and analysis. Results: results of experiments, analysis, studies and generalization of the research led to the new patented designs of foundations with broadening. Conclusions: we formulated the new conceptual-system approach in the theory of shape formation of structures of pile foundations with broadening.

Competitiveness of construction enterprises is the most important characteristic of the enterprise activity, which every business entity must constantly evaluate and undertake various kinds of measures to increase it. The development and implementation of these activities should be carried out with a clear understanding of the content of the enterprise competitiveness, and also by forming and analyzing the list of factors that affect the competitiveness. Subject: competitiveness of construction industry enterprises. Research objectives: reflecting the content of the notion of enterprise competitiveness and the main factors of its provision in the construction industry. Materials and methods: in the process of research, we applied the principles of ascent from abstract to specific, the unity of logical analysis, systematization, structuring and generalization. In the process of writing the paper, we used research and educational literature, articles in periodicals, Internet sources. Results: it is proposed to adhere to an integrated approach, according to which the competitiveness of an enterprise should be understood as the ability of an enterprise to conduct activities in the market, outrunning competitors, effectively using its own internal capabilities and taking into account environmental factors, paying attention to market conditions, features of regional development, characteristics of the industry, and at the same time, making sufficient profit that allows the enterprise to increase its potential. It is important to note that the factors of ensuring the competitiveness of the enterprise are mostly divided into external and internal ones, which, of course, is suitable for construction companies because they are open systems influenced by factors of the external and internal environment. The conducted analysis of the external factors allowed us to divide them into four groups: world-class factors, macro-level factors, meso-level factors and micro-level factors. In turn, the internal factors were grouped as follows: production factors, financial and economic factors, intellectual factors. A detailed study of these factors led to the conclusion that they can have both a negative and a positive impact. Conclusions: the conducted research has allowed us to define the basic directions which promote increase of competitiveness of building enterprises. Among all such directions, the following ones should be highlighted: creation of an optimum volume of industrial and financial funds; availability of qualified personnel in the organization; application of modern technologies and innovative processes, effective marketing tools; execution of construction works taking into account the norms and rules established by the Russian legislation.

Subject: the article considers the possibility of using wild-growing reeds as an effective heat-insulating material in the construction of buildings for various purposes. The main advantages and disadvantages of reeds are analyzed, and it is shown that according to the thermo-technical characteristics cane can be used effectively as a heat-insulating material. Since the thermal conductivity (thermal resistance) of hygroscopic heat-insulating materials depends on their moisture content, a series of experiments was conducted to assess the moisture saturation of natural reeds under conditions of high air humidity. The obtained results were processed to obtain mathematical models for consumption of moisture by reeds during the material exploitation. Research objectives: creation of a mathematical model for calculating the moisture consumption parameters of reed stalks at high humidity parameters of the ambient air. Materials and methods: to achieve the goal, an experimental plant was developed for moistening the reed stalks, in which the samples were kept for several days. Three types of reed stalks were selected: stems with a length of 70 mm and an average diameter of 10 mm: 1 - without leaves; 2 - with leaves along the entire length of the cane; 3 - with leaves and nodal septa. Laboratory samples were brought to the state of their natural weight in the author-developed chamber with infrared heaters in the medium of calcined calcium chloride to absorb the moisture. After conducting the experiments, the moistened reed was weighed to determine the moisture saturation. Results: it has been experimentally confirmed that the curves of moisture saturation of reeds have a nonlinear character. The rate of water absorption in the first two days was 7.9 % for the first type, 8.7 % for the second type and 9.8 % for the third type of reeds. After the first two days the rate of water absorption decreased and after eight days (168 hours) was 15.6 % for samples of the first type, 15.9 % for the second type, and 16.3 % for the third type. Over the next ten days (240 hours), the change in the moisture content of the samples remained practically unchanged and amounted to 16.1 % for the samples of the first kind, 16.6 % for the second type, and 17.3 % for the third type. Conclusions: graphic dependencies of the moisture saturation of reeds on duration of exposure to wet media are obtained; limiting values of moisture content for natural reeds are determined on the basis of experiments; mathematical dependencies of moisture saturation on time are obtained, which can be considered as mathematical models for humidity consumption by natural reeds.

Subject: nowadays self-compacting concretes (SCC), the use of which requires no additional compaction, have become widespread for use in densely-reinforced structures and hard-to-reach places. In self-compacting concretes, finely-ground admixtures-microfillers are widely used for controlling technological properties. Their introduction into the concrete mix allows us to obtain more dense structure of concrete. The influence of micro-fillers on water consumption and plasticity of concrete mix, on kinetics of strength gain rate, heat release and corrosion resistance is also noticeable. Research objectives: the work focuses on the development of composition of self-compacting concrete with assigned properties with the use of fly ash based on coal burning waste, optimized with the help of experimental design method in order to clarify the influence of ash and cement quantity, sand size on strength properties. Materials and methods: pure Portland cement CEM I 42.5 N was used as a binder. Crushed granite of fraction 5…20 mm was used as coarse aggregate, coarse quartz sand with the fineness modulus of 2.6 and fine sand with the fineness modulus of 1.4 were used as fillers. A superplasticizer BASF-Master Glenium 115 was used as a plasticizing admixture. The fly ash from Cherepetskaya thermal power plant was used as a filler. The study of strength and technological properties of self-compacting concrete was performed by using standard methods. Results: we obtained three-factor quadratic dependence of strength properties on the content of ash, cement and fraction of fine filler in the mix of fine fillers. Conclusions: introduction of micro-filler admixture based on the fly ash allowed us to obtain a concrete mix with high mobility, fluidity and self-compaction property. The obtained concrete has high strength characteristics, delayed strength gain rate due to replacement of part of the binder with ash. Introduction of the fly ash increases degree of hydration of Portland cement due to the greater water retention capacity, and also contributes to reduction in total capillary porosity of SCC structure.

Subject: the effectiveness of using compositions with the use of basalt fibers is proven, but the composition must be selected depending on the binder and additives chosen. Research objectives: we examine the possibility of waste recycling of basalt fiber production during manufacturing of modified gypsum composite material with improved characteristics. Materials and methods: as a raw material, a gypsum binder of Samara production was used. As a reinforcement additive, a disperse waste of basalt fiber production of Tver region was used. Studying characteristics of the gypsum binder and modified mixture, and also comparative analysis of these characteristics by average density, total porosity, strength in compression and flexure of the gypsum composite were carried out using standard techniques. Results: dependence of physical and mechanical properties of the modified gypsum material on the content of the basalt fiber additive is established. It was found that an increase in concentration of the additive requires an increased water content or additional use of plasticizer. Conclusions: modification of gypsum stone with a mineral basalt additive will increase the strength, density and durability of thin-walled gypsum products, and, consequently, the demand for products due to ensuring their high quality in transportation and installation.

Subject: ecological justification of modernization of the enterprise within the framework of formation/development of conditions for sustainable development of industrial city. Research objectives: selection of a complex of the technical and organizational decisions that allow us to reach target (permissible) limits of dispersion of harmful emissions, thereby, having minimized the risks of damage to the environment and health of the population. Materials and methods: as primary materials, we used forms of the state statistical reporting “2tp-air”, volumes of maximum permissible emissions of the enterprise-the model site, data about technical and organizational decisions to reduce emissions to the atmosphere. The main methods of the research: geoinformation modeling, functional zoning, the structural analysis. Results: we simulated dispersion of priority pollutant of the leading source of construction dust emissions in the region, and we classified, by the degree of ecological and hygienic risk, the territory of the model site - town of Mikhaylovka. The activities to reduce the range of dispersion of harmful emissions are selected in the form of modernization of technological processes, installation of dust filters, improvement of the ventilation system, carrying out other organizational and technical activities to prevent the spread of dust on the territory of the enterprise and beyond. The environment protection effect of the activities proposed for realization is estimated. Proposals for further development of the analyzed industrial city are formulated. Conclusions: 1. The proposed solutions on modernization of the enterprise allow us to reduce the range of dust dispersion in concentrations that are more than maximum permissible concentration (MPC) by 2.6 times (bringing them to the required limits); 2. The population living under the influence of dust in concentration of 0.5-1 MPC, for which there is a risk of long-term health effects, will be reduced from 43 000 to 6 000 people; 3. The proposed activities for reduction of dust dispersion limits in all rhumbs contributes to the urban development of the previously contaminated territories, for example, for recreational purposes; 4. Various combinations of engineering and organizational solutions of modernization of the enterprise allow us to control ecological and hygienic risks on the territory depending on the priority goals, plans, needs for urban development of the industrial city.

Subject: the results of the analysis of the dynamics of changes in the quality of surface waters in the Lower Volga basin are presented based on the processing of statistical data on the long-term monitoring of their contamination degree. Significant all-season excesses of the maximum permissible values for the concentration of a whole range of background and anthropogenic pollutants in water were recorded. We identified the shortcomings of implementation of the existing methods that allow us to assess the dynamics of the state of the water basin ecosystem and choose the most essential parameters for constructing a mathematical model of selection of the most effective wastewater treatment technology. Research objectives: selection and evaluation of the input parameters of the mathematical model, the implementation of which will ensure the search for the optimal technology and appropriate technical solutions for cleaning surface sewage. Materials and methods: the conducted study is based on a comprehensive assessment of a wide range of hydro-chemical indicators of contamination of discharged wastewater in controlled locations using statistical methods for processing experimental data. Results: we identified the most essential parameters that allow us to form a conceptual model, and we determined the degree of their influence on the selection of the optimal solutions and methods of wastewater treatment. Conclusions: conclusions obtained during the study indicate the need for creation of a mathematical model of assessment of the quality of surface sewage treatment in urbanized areas for improvement of technological parameters of treatment facilities.

Subject: a regional construction cluster, which is viewed as a complex system territorially localized within the region, consisting of interconnected and complementary enterprises of construction and related industries that are united with local institutions, authorities and cooperating enterprises by heterarchic relations. Research objectives: development of multi-agent simulation model that allows us to examine the business-processes in the regional construction cluster as a complex heterarchical system. Materials and methods: we formulate the mathematical problem for description of processes in a heterarchic system as in a special multi-agent queueing network. Conclusions: the article substantiates application of the decentralized approach which is based on the use of agent methodology. Several types of agents that model elementary organizational structures have been developed. We describe the functional core of the multi-agent simulation model characterizing the heterarchic organizational model. Using the Fishman-Kivia criterion, the adequacy of the logical functioning of the developed model was established.

Subject: automation of calculation of dynamic characteristics of the device being designed in the system of conceptual design of sensor equipment, structurally-parametric models of dynamic processes and algorithms for the automated calculation of the qualitative characteristics of elements of the information-measuring and control systems (IMCS). The stage of conceptual design most fully determines the operational characteristics of technical systems. However, none of the information support systems of this stage provides an opportunity to evaluate the performance characteristics of the element being designed taking into account its dynamic characteristics. Research objectives: increasing the effectiveness of the evaluation of dynamic characteristics of sensitive elements of the information-measuring and control systems of a smart house. Materials and methods: when solving the problems posed, the mathematical apparatus of system modeling was used (in particular, the energy-information method of modeling processes of various physical nature that occur in the sensor equipment); the main provisions of the theory of automatic control, the theory of constructing computer-aided design systems, the theory of operational calculus; basics of conceptual design of elements of the information-measuring and control systems. Results: we compared the known automated systems for conceptual design of sensors, highlighted their advantages and disadvantages and we showed that none of these systems allows us to investigate dynamic characteristics of the element being designed in a simple and understandable for engineer form. The authors proposed using energy-information method of modeling for the synthesis of operation principles of sensors and analysis of their dynamic characteristics. We considered elementary dynamic chains and issues of synthesis of parametrical structural schemes that reflect the dynamics of the process with the use of mathematical apparatus of operational calculus. We developed the project of automated system of the conceptual design of the sensor equipment that allowed us to visualize construction of the parametrical structural schemes and representation of evaluation results of the dynamic characteristics. Conclusions: it was shown that the energy-information models of chains of various physical nature can be used for synthesis of parametrical structural schemes with dynamic links. The mathematical apparatus was developed for evaluation of dynamic characteristics of parametrical structural schemes in analytic form. We also presented the information flow diagram and the functional model of the subsystem of synthesis of sensor operation principals with allowance for dynamic characteristics.

Subject: due to the existence of shabby and hazardous dwelling, the housing problem is one of the most relevant problems in the social sphere of the Astrakhan region. The Astrakhan regional construction cluster includes the significant number of the construction organizations, the servicing organizations, which are engaged in the training of personnel for construction, the banks and other credit institutions, which provide the population with mortgage loans, and also regional, municipal authorities and public organizations. The regional construction cluster is the developing social and economic system of heterarchical type. The heterarchy combines both elements of hierarchy and elements of the market relations. Therefore, the task of creation of a common information space of a regional construction cluster on the basis of mathematical, functional and information-logical models is relevant. Research objectives: use functional and mathematical modeling of heterarchical system of a regional construction cluster for development of its information portal. Materials and methods: for creation of structurally-functional model of a regional construction cluster, the methodology of structural analysis in notations of IDEF0, IDEF3, Swimlane was used. As a tool for structurally-functional simulation, we used CASE-tool - AllFusion Process Modeler r7. The mathematical description of logic of regional construction cluster management is based on the theory of sets. Results: the complex of functional models with the set-theoretic description of the system was developed. The business-process model in a notation of IDEF0 well reflects the process hierarchy that best describes the hierarchical communications prevailing in stable functioning of the regulated processes. For its creation the SADT technology was used. When the external disturbances affect the socio-economic system (SES), inertial hierarchical management ceases being effective and the advantage is given to horizontal managing directors of communication for description of which and for reflection of logic of processes it is more appropriate to use the model of the IDEF3 notation. For explicit description of roles and responsibility of performers of specific processes, it is expedient to use the chart SwimLane, which is variety of the chart IDEF3, in order to achieve the unified information environment of a regional construction cluster. The logic of process interaction reflected in the chart SwimLane was described mathematically by creation of a set-theoretic model. Conclusions: All developed models form a basis for further information-logical and physical design of the unified information environment of the Astrakhan regional construction cluster. Computer support of the functioning of such a complex system will allow us to considerably increase its efficiency.