This article discusses the theoretical order and practical solution of the problem of calculating the transverse vibrations of a thermosetting polymer self-supporting shell pipe " Furanflex».Сalculation scheme with a finite number of degrees of freedom.The pipe is evenly fixed in height.The procedure for creating a universal calculation algorithm for determining the natural frequencies of pipe vibrations is considered in detail.When creating an algorithm and calculating natural frequencies, determining coefficients, plotting plots, the Mathcad software package is used.When creating an algorithm and calculating natural frequencies, determining coefficients, plotting plots, the Mathcad software package is used. The article may be of interest to design engineers, specialists in calculating the dynamics and strength of structures and specialists of heat-generating companies and thermal power plants, teachers and students of universities in the construction industry.

Keywords: eigenvalues, polymer tube "furanflex", eigenvalues of the matrix

The article presents theoretical calculations and studies of the possibility of parametric oscillations and parametric resonance arising in a polymer self-supporting thermoplastic pipe "Furanflex". Тheoretical calculations of the possibility of asymmetric parametric oscillations and parametric resonance are considered.The Furanflex thermoplastic, polymer liner is offered as a variant of a separate gas exhaust trunk during the reconstruction of boiler rooms and thermal power plants by heat generating companies.The description and calculation of resonant phenomena for asymmetric parametric oscillations are described in detail.Detailed mathematical transformations of differential equations of parametric oscillations are given.The article provides a detailed description and analysis of the occurrence of parametric oscillations. Examples of symmetric and asymmetric parametric oscillations are considered.Information and conclusions of the presented work are intended for a different range of readers, teachers, designers, students of construction specialties.This article should be of interest to utility managers and heat generating companies .

Keywords: chimney, ventilation duct, repair, restoration of the chimney,protection of the chimney, lining, furanflex, thermoplastic liner,perimetric oscillation

The article presents theoretical calculations and studies of the possibility of parametric oscillations and parametric resonance arising in a polymer self-supporting thermoplastic pipe "Furanflex". The Furanflex thermoplastic, polymer liner is offered as a variant of a separate gas exhaust trunk during the reconstruction of boiler rooms and thermal power plants by heat generating companies.The article provides a detailed description and analysis of the occurrence of parametric oscillations. Examples of symmetric and asymmetric parametric oscillations are considered.Information and conclusions of the presented work are intended for a different range of readers, teachers, designers, students of construction specialties.This article should be of interest to utility managers and heat generating companies .

Keywords: chimney, ventilation duct, corrosion, repair, restoration of the chimney, condensate,protection of the chimney, lining, furanflex, thermoplastic liner,perimetric oscillation

The article presents a theoretical description and procedure for calculating the three-hinged arch parabolic outline. The technique of creation of the universal program in a computing complex of Mathcad for various options of vertical loading is in detail stated. The method of calculation of a three-hinged statically determined arch is considered in detail. The order of design calculation is given in the article. The technique of the automated creation of diagrams of internal power factors of an arch design is offered. A detailed description and analysis of the design scheme of three-hinged arch is given.

Keywords: three-hinged arch, statically definable arches, arched structures, parabolic outline, diagrams of internal power factor

The description of modern technologies for the protection, repair, reconstruction of chimney and ventilation ducts method of mounting a thermoplastic polymer tube Furanflex. A detailed description and analysis of the advantages and disadvantages of this technology. The technique of eliminating the problem of chimney destruction due to the impact of condensate is presented. A brief review of the existing alternative methods of protection and repair of chimneys. The advantages and disadvantages of these alternatives methods are briefly described. Data and conclusions of the presented work may be interesting for the widest circle of readers, builders, architects, owners of cottages . The article may be of interest to those who are just planning to start building their own homes, as well as managing utility companies on the balance of which is the old houses

Keywords: chimney, ventilation duct, corrosion, repair, restoration of the chimney, condensate,protection of the chimney, lining, furanflex, thermoplastic liner

The article presents the description of the creation of modern multitube designs of industrial pipes using the self-supporting thermoplastic polymer pipe Furanflex.The variant of the device of separate gas-exhaust trunk at reconstruction of boiler rooms and CHP by the heat-generating companies is offered. There is a specific example which gives description of technology the installation of industrial pipes Furanflex .The detailed description and the analysis of advantages and disadvantages of this technology by means of which it is possible to get rid of a problem of destruction of a chimney owing to influence of condensate is given forever. The article provides a brief overview of the existing alternative methods of protection and repair of chimneys with a brief description of the advantages and disadvantages.Data and conclusions of the presented work maybe interesting for different circle of readers, builders, designers-designers, architects.This article should be of interest to the heat-generating companies

Keywords: chimney, ventilation duct, corrosion, repair, restoration of the chimney, condensate,protection of the chimney, lining, furanflex, thermoplastic liner,corrosion, pipe repair, multitube designs of industrial pipes