The paper considers the dynamics of drought periods based on meteorological data for a multi-year period. The research area covers the basins of the Sokolovsky reservoir and the Taganrog Bay. In the course of the study, the following tasks were performed: climatograms were constructed, a correlation analysis of the course of the total amount of precipitation and the course of average annual temperatures was performed, the deviation of air temperatures from the climatic norm for the considered areas was revealed. The tendency to increase the dry period in the Rostov region from north to south has been revealed, which may have an adverse effect on the hydrological regime of water bodies.

Keywords: dry period, Sokolov reservoir, Taganrog Bay, Rostov region, drought, climate, climate data, precipitation, air temperature

The article deals with the effectiveness of high-strength concrete for the design of concrete columns on the example of 20-storey residential building in Rostov-on-Don. The results of the ground floor columns calculations for different types of concrete strength are presented. The columns are presented in two variations. The first variation is 600x600 B25 from the second underground floor to the tenth floor and 500x500 B25 from the eleventh to twenty-fifth floor. The second one is 500x500 B60 from the second underground floor to the seventh floor, 400x400 B60 from the eighth to the eleventh and 400x400 B25 from the twelfth to the twentieth floor. The analysis of the study results showed the technical and economic efficiency of the use of high-strength concrete (in particular, concrete class B60) due to increasing the strength characteristics of the compressed elements. This is also due to reducing the cross-sectional size and weight of the columns, saving reinforcement, causing a reduction in the cost of elements as a whole.

Keywords: high-strength concrete, compressed elements, construction of tall buildings, columns, Lira-SAPR, calculation of structures

From the pilot section of the gas pipeline, after ten years of operation, specimen-witnesses were seized. The gas pipeline consists of reinforced polyethylene pipes with an average adhesive reinforcing layer. The results of mechanical tests of model samples are given in the article. Investigations of the deformation-strength properties of the witness specimens show a decrease in the temperature of the viscous-brittle transition to -15 ° C. These results indicate a deterioration in the adhesion between the outer layers of PE80 and the middle technological layer. Good adhesion led to the emergence and development of a fragile crack. Stability tests at constant pressure showed satisfactory results, not a single sample collapsed. According to the research data, the reinforced polyethylene pipe did not deteriorate its deformation-strength properties for ten years of operation of the gas pipeline under pressure.

Keywords: Reinforced polyethylene pipe, specimen-witnesses, adhesion, stretching, viscous-brittle transition, resistance at constant internal pressure

Implemented assessment of the mechanical behavior of reinforced synthetic fibers of polyethylene pipes, which are provided in the construction adhesive layer connecting the reinforcing plastic shells and pipes. Presents the results of quasistatic tests the tensile strength of model samples in the range of low climatic temperature and speed tests 25-100mm/min. The dependence of the temperature of ductile-brittle transition in the mechanism of destruction of model samples of speed tests, which at 100 mm/min up to 0°С. The mechanism of destruction of a model sample of the reinforced polyethylene pipe, consisting in cracking of the technological layer connected with layers of PE80 which ability to braking of a crack and defines transition from viscous destruction to fragile at fall of temperature of tests is interpreted. It appears that this result emphasizes the need to further clarify and harmonize the existing regulatory requirements on the use and operation of pipes and polyethylene pipelines in cold climate regions.

Keywords: reinforced polyethylene pipe, pipeline, temperature, adhesive layer, strength, crack, viscosity, brittleness, cold climate