Objectives. The possibility of modeling wind flow during the design of buildings with complex geometric shapes in order to determine comfort parameters and zones is considered.

Methods. The investigation of the impact of wind on a cylindrical building was carried out using Ansys 15.0 software.

Results. A finite element model of a modern art museum building having a complex geometric shape is developed for the calculation of the wind flow and the definition of comfort zones. The computational region is chosen such that its borders do not affect the calculation results. The maximum wind speed is assumed to be 44 m/s at an altitude of 10 m from the ground level, this being the maximum in the region of Novorossiysk. The topography of the earth's surface around the model was considered flat. The surface of the building was assumed to be smooth while the surface of the surrounding terrain was assumed to be rough with a roughness parameter of 0,1 m. The parameters of the building orientation relative to the wind rise were varied during the numerical modeling. Three variants of computational models with varying building location and its geometric characteristics are developed. In the first variant, the building model is stretched along the X-axis; in the second variant, the acute angle of the building model's contour is oriented along the Y-axis; in the third variant, the building model is located and oriented along the Y-axis with its obtuse angle of the external contour of the building. The calculation results of a cylindrical building for wind impact correspond to SP 20.13330.2011. The comfort parameters and zones of a building having complex geometric shape are defined by means of numerical modeling of the wind flow. The discrepancy between the object's normative characteristics and the research results is revealed during the calculation of the wind load.

Conclusion. The recommendations are given for choosing the optimal location of the museum building, taking into account the comfort parameters and the greatest wind pressure; the geometric shape of the outer contour affects the location of the zones of reduced comfort; a sharp change in the boundaries of the outer contour leads to the appearance of increased pressure and wind speed and, as a consequence, a change in the direction of the vortex flows; it is necessary to apply the finite element method when modeling the wind impact for buildings of complex geometric shapes; sudden changes in the object's contour should be avoided when designing buildings and structures. 

Objectives. The main idea of the present study was the production of polymer composites based on synthetic isoprene elastomer and low-density polyethylene containing nanoparticles of carbon black and aluminium in various amounts.

Methods. An exponential approach was used throughout the study to better control the region of small additives; this control was impossible to achieve using a linear distribution of nanofillers among the small additives. The composites were filled with nanosized aluminium and DG-100 carbon black particles with a specific adsorption surface of 100 m2 /g and having an average particle size of 20-30 nm. Electrophysical parameters were measured by conventional techniques of electron microscopy, electron shadow microscopy and hydrostatic weighing. Maxwell-Wagner theory and polarisation model were applied.

Results. For a composite containing 80% of isoprene synthetic rubber (SCI-3) and 20% of low-density polyethylene, the dielectric permeability and specific volume resistivity dependences were studied experimentally and their graphs were plotted against the concentration of nanosized particles of aluminium and carbon black fillers. The features of these curves were considered. It is shown that, for small amounts of Al and carbon black nanoparticles in the composite, significant changes (extrema) take place on the curves ԑ '= ԑ' (C) and ρᵥ = ρᵥ (C), which do not conform to the Maxwell-Wagner polarisation model. For some heterogeneous polymer mixtures, a distribution of carbon black particles was observed that led to a superadditive electrical resistance.

Conclusion. It is shown that for small amounts of Al and carbon black nanoparticles in composite materials, significant changes (extrema) take place on the curves ԑ '= ԑ' (C) and ρᵥ = ρᵥ (C) that do not fit within the framework of the Maxwell-Wagner polarisation model.

Objectives. In order to improve the accuracy of calculations in the design of ship shafting systems, the problem was to determine the stiffness coefficient of the stern bearing material taking into account its geometric dimensions.

Methods. The contact problem of interaction between a propeller shaft incorporating a stern bearing is considered. The calculations are reduced to solving the contact problem of a beam on an elastic base, which simulates a propeller shaft and a deadwood stern bearing in the design scheme.

Results. The characteristics of the mechanical and elastic properties of the Winkler base are given. Formulas are composed for determining the components of the elastic forces and deformation values. A study was carried out using a special device for determining the stiffness coefficient of samples made of caprolon. Dependency was obtained for the determination of the stern bearing stiffness coefficient, taking into account its geometric dimensions and shape. Two batches of sample inserts were made for the investigations: samples of different lengths (110, 90, 70 mm) with a thickness of 7 mm, and samples 110 mm long with various thicknesses (6-7 mm). The samples were compressed under the impact of a defined load by a test laboratory hydraulic press of P-125 type. The values of sample offset during compression were measured by an alesometer according to GOST 4651-82. The results obtained were statistically processed with a confidence level of a = 0.95. Based on the average values of the results obtained, a dependency graph of the sample compression value was plotted against the defined load for different lengths of the sample. The average value of the sample stiffness coefficient was determined in the proportional zone. A nonlinear law of sample deformation was observed during a further load increase, as evidenced by a rapid change in the length and shape of the samples.

Conclusion. The proposed method for determining the stiffness coefficient of the stern bearing, taking into account its dimensions, allows the system's stiffness characteristic to be determined more accurately, and can be used in the design calculations of the ship's shaft. The reliability of the result is assured by rigorous mathematical calculations.

Objectives. The well-known discontinuous solution method, used in the study of infinite and semi-infinite domains, is generalised during the construction of solutions in Fourier series. This makes it possible to reduce the problem of the mechanics of a deformable solid for a limited region containing cuts or inclusions to the solution of an integral equation (or system) with respect to discontinuities of the functions being defined.

Methods. The method was implemented through the application to the solution of the theoretical elasticity problem for a pipe section (plane deformation) weakened by an internal radial crack. The pipe was loaded with hydrostatic pressure and a thin coating is applied on its inner surface, improving its physical and mechanical properties. The applied method, combined with the conventional integral transformation, can be effectively used in the construction of discontinuous solutions of three-dimensional problems of the theory of elasticity.

Results. Specially formulated boundary conditions were used as a coating model. In order to verify the adequacy of the adopted model, a series of numerical experiments was carried out. In some cases, calculations were carried out for the cross-section of a coated pipe in finite-element ANSYS and COMSOL software packages. In others, benefiting from the extensive capabilities of the FlexPDE software package, an uncoated pipe model was constructed, although using special boundary conditions. Comparison of the results obtained made it possible to ascertain the adequacy of the models constructed across a certain range of geometric and physical parameters.

Conclusion. The problem is reduced to the solution of a singular integral equation with a Cauchy kernel with respect to the derivative of the jump in the tangential component of the displacement vector on the crack edges. Its solution is determined by the collocation method with a pre-selected feature. The ultimate goal of the study is to determine the values of the strain intensity coefficient at the apices of the crack.

Objectives. Spin nanoelectronics facilitate fundamentally new ways of encoding and encrypting information implemented using photon spins in fibre-optic data transmission lines. The article discusses the possibility of creating a spin LED emitting circularly polarised light.

Methods. In a spin LED, spin-polarised carriers are injected from a ferromagnetic contact combined with a quantum well.

Results. Quantum selection rules for describing recombination establish a connection between the circular polarisation of light, emitted along the normal to the surface, and the spin polarisation of the electrons.

Conclusion. Physical methods for coding and transmitting information by means of polarised spin devices using the spin degree of freedom are formulated. The configuration principles of a polarised radiation generator (spin LED) are proposed. The approach is based on a heterostructure containing the quantum well InGaAs / GaAs (luminescent layer) and the ferromagnetic layer GaMnAs. It is established that the quantum well emission line is split into two circularly polarised components, which opens up new possibilities for coding and transmission of information in fibre-optic data transmission lines by the methods of polarisation modulation. The circular polarisation of the photoluminescence from the InGaAs / GaAs quantum well is caused by the magnetisation of a nearby ferromagnetic GaMnAs layer. Acknowledgments The author is grateful to the employees of NIFTI UNN named after N.I. Lobachevsky Yu.A. Danilov and M.V. Dorokhin for samples, the employee of ISSP RAS S.V. Zaitsev for optical measurements, the employee of the Moscow State University of Railway Engineering (MIIT) V.P. Solov'ev for useful discussions. The work is partially supported by the grant of the Russian Foundation for Basic Research No. 16-07-00863a and the RF President's grant MK-5754.2016.3. 

Objective. The development of a device for the piecewise-linear approximation of a transient response for controlling an automated system of the production diagnosis of electronic component parameters on functional cells.

Methods. A new measuring input circuit was developed for the control of defective electronic components on functional cells in order to obtain the integral transient response, provided that circuit parameters can be programmatically altered. In this case, there is no need to exclude the shunting influence of neighbouring elements on functional cells, since all parameters of all electronic equipment connected to the controlled points are taken into account and will influence the formation of the transient process.

Results. The input measuring integrated circuit is capable of controlling the transient responses of both individual electronic components and their groups, consisting of various types of active and passive electronic components. The dependency between the systematic error in the piecewise-linear approximation of the transient response of the electronic components on functional cells and the time constant (T) of the input circuit of the measurement unit is established. The minimum value of the systematic error will be obtained with a time constant of the input circuit equal to 0.001 sec.

Conclusion. The information form converter in the automated production diagnostic system for monitoring transient response from the diagnosed electronic components after the stimulating voltage drop has been applied will significantly reduce the time for monitoring each functional cell due to a faster conversion process and a simpler process for comparison with reference. 

Objectives. The aim of the study is to develop a construction design that increases the intensity of heat exchange between media and optimises the energy and mass dimensions of the instrument indicators.

Methods. A method for the theoretical investigation of thermoelectric heat transfer intensifiers is used, which, by means of forced air flows along the junctions of thermoelements, provides a higher coefficient of heat exchange between media moving in transport zones with altering temperature.

Results. The construction of a thermoelectric heat transfer intensifier is proposed, which uses fan assemblies to force air flow in the respective gaps between the junctions of the thermoelements and the media moving in transport zones to increase the heat transfer coefficient. A device model based on the solution of the heat balance equations for media flows in transport zones, thermoelectric battery surfaces and gaps between transport zones and battery surfaces for direct flow conditions is considered. Theoretical studies of the heat transfer intensifier using the developed model were carried out. The dependencies of the media temperature alterations at the output of the heat transfer intensifier on the value of the heat transfer coefficient between the junctions of the thermoelectric battery and the air medium in the gap are determined for a fixed value of the thermoelectric battery supply current equal to 5 A.

Conclusion. It is established that an increase in media temperature difference at the input contributes to a sharper decrease in the dependencies of the limiting lengths of the thermoelectric battery on the heat transfer coefficient between the junctions of the thermoelectric battery and the air medium in the gap at a constant supply current. 

Objective. The development of light-emitting bipolar semiconductor structures having a low level of parasitic heat release.

Methods. A method for converting thermoelectric heat in bipolar semiconductor structures into optical radiation to divert the excess energy into the environment was developed. At the same time, the cooling effect on thermoelectric junctions remains. Instead of an inertial process of conductive or convective heat transfer, practically instantaneous heat removal from electronic components to the environment takes place.

Results. As a result, light-emitting bipolar semiconductor structures will allow more powerful devices with greater speed and degree of integration to be created. It is possible to produce transparent LED matrices with a two-way arrangement of transparent solar cells and mirror metal electrodes along the perimeter. When current is applied, the LED matrix on one of the transitions will absorb thermal energy; on other electrodes, it will emit radiation that is completely recovered into electricity by means of transparent solar cells following repeated reflection between the mirror electrodes. The low efficiency of solar cells will be completely compensated for with the multiple passages of photons through these batteries.

Conclusion. Light-emitting bipolar semiconductor structures will not only improve the reliability of electronic components in a wide range of performance characteristics, but also improve energy efficiency through the use of optical radiation recovery. Semiconductor thermoelectric devices using optical phenomena in conjunction with the Peltier effect allow a wide range of energy-efficient components of radio electronic equipment to be realised, both for discrete electronics and for microsystem techniques. Systems for obtaining ultra-low temperatures in order to achieve superconductivity are of particular value. 

Objectives. The main objective of the study was to regulate the thermal regime and ensure the reliability of electronic equipment

Methods. In order to conduct experimental studies of the thermoelectric cooling system using heat pipes, a stand was assembled on which the developed and manufactured prototype was studied. The object of the experimental studies was a prototype cooling system, consisting of a thermoelectric battery made of conventional unified thermoelectric materials of ICE-71 type. The solution of the research problems carried out by the method of reduction to ordinary differential equations (Kantorovich method) provides acceptable accuracy for such a class of problems.

Results. A design of a telecommunication equipment cabinet with a thermal management system based on the use of heat pipes and thermoelectric cooling units is proposed. A mathematical model for the determination of the thermal field in the cabinet volume is considered; an experimental stand for the prototype study is described; the results of experimental studies for various power sources of heat release are presented.

Conclusion. Experimental studies confirm the operability of the developed cooling system for cabinets with telecommunication equipment; this cooling method has advantages over conventional forced or natural cooling; the temperature in the block volume and the peak values of the heat sources are significantly reduced; at dissipation powers on one board within 50 W there is no need to use special means to remove heat from hot junctions of the thermoelectric battery.

Objectives. The aim of present paper is to minimise the errors in the approximation of experimentally obtained acceleration curves.

Methods. Based on the features and disadvantages of the well-known Simoyu method for calculating transfer functions on the basis of acceleration curves, a modified version of the method is developed using the MathLab and MathCad software. This is based on minimising the sum of the squares of the experimental point deviations from the solution of the differential equation at the same points.

Results. Methods for the implementation of parametric identification are analysed and the Simoyu method is chosen as the most effective. On the basis of the analysis of its advantages and disadvantages, a modified method is proposed that allows the structure and parameters of the transfer function to be identified according to the experimental acceleration curve, as well as the choice of optimal numerical values of those parameters obtained for minimising errors in the approximation of the experimentally obtained acceleration curves.

Conclusion. The problem of optimal control over a complex technical facility was solved. On the basis of the modified Simoyu method, an algorithm for the automated selection of the optimal shape and calculation of transfer function parameters of dynamic elements of complex technical objects according to the acceleration curves in the impact channels was developed. This has allowed the calculation efficiency of the dynamic characteristics of control objects to be increased by minimising the approximation errors. The efficiency of the proposed calculation method is shown. Its simplicity makes it possible to apply to practical calculations, especially for use in the design of complex technical objects within the framework of the computer aided design system. The proposed method makes it possible to increase the accuracy of the approximation by at least 20%, which is an important advantage for its practical use. 

Objectives. The aim of the work is to determine the relationship between generalised criterion and target programming methods.

Methods. The paper considers the aggregation operation that underlies many decision-making procedures used in input-output models, in neural network technologies and in the study of multi-purpose systems. The use of certain metrics within the framework of target programming can lead to solutions that are not Pareto-optimal. Therefore, in targeted programming, a significant place is given to finding the conditions under which the use of one or another metric obviously leads to Pareto-optimal solutions. The necessary (Carlin's theorem) and sufficient conditions of Pareto-optimality are known to perform the additive reduction. For a generalised criterion on the basis of order operators of weighted aggregation, two theorems proven by the author (the theorem on the inclusion of the set of Pareto-optimal solutions into a set of effective solutions and the Pareto optimality theorem for the solution obtained) are presented.

Results. The proof of the Pareto optimality theorem of the solution is given, maximising the generalised criterion obtained on the basis of the order operations of weighted aggregation, which justifies the use of operations of this type for solving the problems of vector optimisation or multicriteria choice. The theorem on the existence of an additive reduction for a metric is true only in the particular case and is based on Carlin's theorem, according to which a subset of Pareto-set points maximises some additive reduction.

Conclusion. In the paper a relationship between the additive reduction and metrics methods is established. An assertion concerning the relationship between the parameters of the distance function in the target programming method and the weighting coefficients of the additive reduction is formulated and proved, which ensures the equivalence of the optimal Pareto solutions. 

Objectives. The aim of the study is to determine earthquake hypocentres with the simultaneous use of both the sphere and hyperboloid methods of calculation, providing minimal possible error due to the appropriate choice of seismic sensors.

Method. A method for determining the hypocentre of earthquakes is proposed that uses methods of spheres and hyperboloids for calculations making it possible to minimise error due to the appropriate choice of seismic sensors. In this case, we proceed from the fact that the circumference is the geometric position of the intersection points of the hyperboloid and the sphere, provided that the focus of the hyperboloid and the centre of the sphere are located on one straight line.

Results. In order to find the coordinates of the earthquake focus, it is necessary to use the data of the third seismic sensor, which should not lie on the same line with the first two. If the third seismic sensor determines the distance to the earthquake focus according to the difference in travel times of the longitudinal and transverse seismic waves, then the geometric location of the earthquake focus will be the sphere. The point of intersection of this sphere with the abovementioned circumference is the earthquake focus. When locating the dependency of the earthquake hypocentre determination error in the relative location of the two seismic sensors, the values of the longitudinal and transverse seismic wave velocities, the difference in the travel times of these waves to the seismic sensors and the difference in the travel times of the longitudinal seismic wave to the two spaced seismic sensors are proposed for use in the calculations. Using the two methods listed above, it is possible to determine the error direction in determining the distance from the earthquake focus to the seismic sensor. For this purpose, the distance  is retrieved between the epicentres of earthquakes, calculated using the combined method (spheres and hyperboloids) and the sphere method. The same distance  is determined after the addition of the deliberate error t to the run time differences of the seismic waves Δt + t. The value of the  -  difference leads to a conclusion concerning the direction of the error.

Conclusion. The determination of the direction of errors is possible using the methods of spheres as well as the method of spheres and hyperboloids. The method having multidirectional errors in measuring the distances to the focus has fewer errors in determining its coordinates as compared to the method of spheres described in the work, while with co-directional errors, conversely, the errors arising when using the combined method are higher. 

Objectives. The aim of present work was to carry out mathematical modelling of heat transfer with symmetrical heating in flat channels and round pipes with rough walls.

Methods. The calculation was carried out using the L'Hôpital-Bernoulli's method. The solution of the problem of intensified heat transfer in a round tube with rough walls was obtained using the Lyon's integral.

Results. Different from existing theories, a methodology of theoretical computational heat transfer determination for flat rough channels and round pipes with rough walls is developed on the basis of the principle of full viscosity superposition in a turbulent boundary layer. The analysis of the calculated heat transfer and hydroresistivity values for flat rough channels and round rough pipes shows that the increase in heat transfer is always less than the corresponding increase in hydraulic resistance, which is a disadvantage as compared to channels with turbulators, with all else being equal. The results of calculating the heat transfer for channels with rough walls in an extended range of determinant parameters, which differ significantly from the corresponding data for the channels with turbulators, determine the level of heat exchange intensification.

Conclusion. An increase in the calculated values of the relative average heat transfer Nu/NuGL for flat rough channels and rough pipes with very high values of the relative roughness is significantly contributed by both an increase in the relative roughness height and an increase in the Reynolds number Re. In comparison with empirical dependencies, the main advantage of solutions for averaged heat transfer in rough flat channels and round pipes under symmetrical thermal load obtained according to the developed theory is that they allow the calculation of heat exchange in rough pipes to be made in the case of large and very large relative heights of roughness protrusions, including large Reynolds numbers, typical for pipes of small diameters and narrow flat channels. An increase in the relative heat exchange in air due to an increase in the relative height of the roughness or the Reynolds number is accompanied by an even more significant increase in the hydraulic resistance. Calculated data on averaged heat transfer obtained in the work showed that in the range of determinant parameters for flat rough channels with symmetrical thermal loading, the average heat transfer is higher by (4.811.7)% as compared to round rough pipes – all other things being equal. 

Objectives. The aim is to improve the mathematical model of the motion of channelfill deposits in terms of clarifying one of the main relationships on which the sediment flow rate depends: the frequency of pulsations of the vertical fluid velocity component with hydraulic flow parameters.

Methods. The mathematical model is developed using probability theory and the theory of runs of random processes, taking into account the normal distribution of the horizontal and vertical components of the instantaneous flow velocities and the Rayleigh law of the distribution of their maxima.

Results. As a result of the modelling, information was obtained concerning the volumes and areas of the zones of influence of increased turbidity on the aquatic bioresources of the Gizeldon River. The operation of the Gizeldon hydroelectric power station have led to the loss of zoobenthos habitats, the destruction of bottom biocenoses, the loss of food organisms of plankton and benthos, a decrease in the fodder base of fish and the direct death of the ichthyofauna. An assessment of the damage caused to aquatic bioresources from the operation of the Gizeldon hydroelectric power station was carried out. As a result, it was proved that the negative influence of the "turbidity loop" in the lower tail of the river, taking into account the critical values of suspended matter concentration in water will be traced for 3.7 km. The amount of damage to aquatic bioresources in physical terms is about 1.5 tons due to the destruction of the fodder base of fish and the deterioration of habitat conditions in the zone of increased turbidity.

Conclusion. The results of mathematical modelling were tested on field data materials and used to calculate the turbidity of the Gizeldon River flow during the reconstruction of the Gizeldon hydroelectric power station. The results of the approbation of the mathematical model of the motion of channel-fill sediment are presented in order to identify the areas of increased turbidity during the assessment of the damage to the water resources of the Gizeldon River. 

Objectives. On the basis of the experimental, theoretical and field studies, an engineering calculation method was developed for assessing the cracking resistance of external enclosing constructions made of cellular concrete, with the maximum gradient development of moisture and carbonisation forced deformations along their thickness, taking into account the relaxation of the shrinkage stresses. In this regard, the aim of the work is to provide technological measures at the manufacturing stage in order to increase the operational cracking resistance of the construction's outer surface layers by reducing the moisture and carbonation shrinkage of cellular concrete by introducing a large or fine porous aggregate in calculated amounts.

Methods. A number of analytical equations were applied to establish the dependence of the shrinkage of heavy concrete of conventional hardness on the amount of aggregate introduced and its elasticity modulus, water-cement ratio and cement consumption, as well as the concrete's moisture content.

Results. Knowing the volumes of the structural aggregate and the cellular concrete mass, as well as their modulus of elasticity, the shrinkage reduction factor of the cellular concrete was calculated with the addition of a lightweight porous aggregate. Subsequently, the shrinkage deformations of concrete in the surface layer of the outer enclosing construction, maximising crack resistance due to moisture exchange and carbonation influences under operating conditions, were defined, taking into account the relaxation of tensile stresses due to creep of concrete.

Conclusion. Theoretical calculations, based on the recommended method of assessing the cracking resistance of cellular concrete enclosing constructions under moisture exchange and carbonisation processes, taking into account the relaxation of shrinkage stresses, showed that in order to exclude the appearance of cracks in wall panels 280 mm thick made of 700 kg/m3 gas ash concrete with elasticity modulus of 2500 MPa, it is necessary to have 70-80% of keramzite or granulated slag, and 50-60% of stone crumb (granite or marble crushed stone) of the volume of cellular concrete in the surface layer of 30-50 mm. 

Objectives. The aim of the work is to find the most rational form of expression of the potential energy of a nonlinear system with the subsequent use of algebraic means and geometric images of catastrophe theory for studying the behaviour of a construction under load. Various forms of stability criteria for the equilibrium states of constructions are investigated. Some aspects of the using various forms of expression of the system’s total energy are considered, oriented to the subsequent use of the catastrophe theory methods for solving the nonlinear problems of construction calculation associated with discontinuous phenomena.

Methods. According to the form of the potential energy expression, the mathematical description of the problem being solved is linked to a specific catastrophe of a universal character from the list of catastrophes. After this, the behaviour of the system can be predicted on the basis of the fundamental propositions formulated in catastrophe theory without integrating the corresponding system of nonlinear differential equations of high order in partial derivatives, to which the solution of such problems is reduced.

Results. The result is presented in the form of uniform geometric images containing all the necessary qualitative and quantitative information about the deformation of whole construction classes under load for a wide range of changes in the values of external (control) and internal (behavioural) parameters.

Conclusion. Methods based on catastrophe theory are an effective mathematical tool for solving non-linear boundary-value problems with parameters associated with discontinuous phenomena, which are poorly analysable by conventional methods. However, they have not yet received due attention from researchers, especially in the field of stability calculations, which remains a complex, relevant and attractive problem within structural mechanics. To solve a concrete nonlinear boundary value problem for calculating structures by algebraic means and using geometric images of catastrophe theory, it is necessary to establish the connection between the mathematical description of the problem being solved, characterised by the functional of the variety of the energy method and universal problems solved on the basis of the fundamental provisions of catastrophe theory. Present work is an effort to revive interest in the methods of catastrophe theory and their use for solving various problems. 

Objectives. The aim of the research is to develop the most effective construction and technological methods for strengthening the bottom of rivers and bays, composed of weak structurally unstable soils, including zones with seismic activity, using pile foundations with broadening and rock filling with micropiles.

Methods. The method of constructing combined transport transitions was applied, consisting of overpasses running over relatively shallow channels from coasts to artificial islands on which the route enters tunnels crossing deep shipping canals.

Results. The foreign experience in the construction of immersed tube tunnels in the construction of transport crossings through the extended river and sea barriers has been analytically generalised. The features, advantages and disadvantages of the construction of immersed tube tunnels in some countries of the world are revealed.

Conclusion. A large number of already constructed and operated transport transits, including immersed tube tunnels, testifies to the advantages of such projects, as compared to other types of transport transitions like bridges and tunnels constructed using mining techniques. Constructiontechnological methods for strengthening the bottom of rivers and bays, composed of weak structurally unstable soils, are proposed. When selecting a design of a bridge to ensure the passage of hightonnage vessels, it is necessary to build large-span bridges on high supports. Weak, structurally unstable soils, deep bedding of bedrock and high seismicity of the area will create serious problems in the construction and operation of such structures. The natural vibration frequencies of the large-span bridges fall into the region of the dominant earthquake frequencies, which can lead to resonant phenomena and damage the structure even under weak seismic influences. Tunnels are less susceptible to seismic impacts, since, unlike ground structures, they don't experience resonance phenomena. When seismic waves pass, the tunnels are deformed in the same way as the surrounding soil massif (if the soil is solid), or much less (if the soil is weak). Deformations are usually small and do not pose a serious danger for tunnel lining. Structural and technological solutions for long transit routes through straits composed of weak soils along the bottom in the territories of disarticulated landscapes can be the most economical, reliable and acceptable when choosing the intersection by transport routes from the point of view of costs, time of construction and use of modern technologies. 

Objectives. The aim of the present work is to study the influence of design parameters on the stress-deformed state of a sprengel crane girder; to compile the tables and corresponding graphs illustrating changes in internal force factors in the characteristic cross-sections of the system elements under consideration. The article describes the study of the stress-deformed state (SDS) of a metal strut-framed crane girder.

Methods. Numerical methods of analysis based on the use of the Green's function are used during solving this problem. A dimensionless parameter is introduced, depending on which the tables and graphs are constructed. According to the known algorithm, the calculations of internal force factors in the sections of the considered construction are performed.

Results. Depending on the dimensionless parameter characterising the geometry and physical features of the system, tables of bending moments and transverse forces are compiled. According to these tables, the appropriate graphs are plotted in order to choose easily the optimal design parameters.

Conclusion. The dependence of the moments and transverse forces on the dimensionless parameter k was found, the corresponding graphs were plotted and the metal costs for the girders were calculated. The minimum values of the moments and transverse forces are established to take place when the dimensionless parameter k values are close to zero. The most economical was a strut-framed crane girder having k = 0.0001. The most uneconomical had k = 0.05 and k =∞. Eventually, the sprengel girders were found to be more profitable as compared to conventional crane girders. In the examples considered in the article, the metal savings amounted up to 14%. The presented methodology allows the calculation and designing of strut-framed crane girders with two racks to be carried out. 

Objectives. The article substantiates the necessity for competitive innovative high-tech construction products at the present stage of modernisation of the construction industry and reveals some peculiarities of their manufacture.

Methods. In the course of the research, a programme-targeted method was applied, underlying the development of a programme for the innovative development of construction production.

Results. Relevant directions of innovative development of construction production are systematised. The world's application experience of a technical regulation parametric model for construction industry product manufacturing is generalised. In order to increase the level of innovative activity of construction organisations, a set of practical measures is proposed whose implementation will ensure the output of competitive building products to the market.

Conclusion. Increasing the competitiveness of construction products is closely connected with the activation of innovative processes: the introduction of high technology (including resource-saving) into production processes and the expansion of the output of innovative products with the best consumer properties capable of successfully competing on the market with foreign counterparts in the context of import substitution strategies. The modernisation of the construction industry on the basis of introduction of hightech production methods specifies new requirements to the professional competencies of personnel producing competitive building products. To solve the set problems, a tool for improving the management mechanism of the innovative activity of construction organisations was proposed, ensuring the integration of institutional and production conditions for the large-scale development of advanced technologies and production of science-intensive types of construction products. 

Objectives. The development of a set of practical measures in order to improve the quality of investment design in industrial construction.

Methods. The basis of research comprises a project management methodology as well as methods for logical and statistical analysis of decisionmaking in investment activities.

Results. A mechanism of inclusion of industrial construction objects into the Federal targeted investment programme is revealed. The sequence of the state expert evaluation of investment projects is determined, which optimises the design solutions aimed at minimising their estimated cost if the investment is made with the involvement of the Federal budget. Qualitative and quantitative criteria are systematised for the integrated assessment of the effectiveness of investment fund usage sent to industrial construction objects.

Conclusion. The consistent implementation of the state investment policy is aimed at developing the scientific-technological and scientific-industrial potential of industrial construction by providing favourable conditions for effective innovation activity, selecting rational investment strategies and priority projects aimed at solving urgent problems of improving the competitiveness of construction. Successful implementation of the state investment policy in industrial construction largely depends on the effectiveness of investment design, starting from the accuracy of the formulation of the investment plan (idea), in which the interests of all participants in investment activities are concentrated and taken into account, and to the development of an agreed set of actions to complete the project. A unified register covering the data on the cost and results of investment projects is proposed to be created with the purpose of facilitating decision-making in the process of allocation of the Federal budget funds, planning of state capital investments and approval of project documentation for new industrial construction projects offered for financing.