No. 4 (2023): Architecture, Construction, Transport

The purpose of the numerical and analytical studies was to analyze the annual temperature deformations of the long-span coating of the Sports Arena building in Tyumen. The structure of covering is made of 1915 grade aluminum alloy and is operated outdoors. Annual differences in outdoor air temperatures led to significant temperature deformations of the building covering in the transverse direction. Comparison of the obtained calculated values of thermal deformations of the roof trusses with the normative limit values made it possible to conclude that the bearing structure of the covering is poor from the point of view of perception of climatic influences. The use of classic approaches to the design of building coverings inside the thermal circuit makes it possible to significantly reduce the risks of defects and damage to structures during their long-term operation. 

Despite the large number of existing solutions, the issue of optimizing the structure of freestanding shallow foundations is still relevant because of poorly studying. The object of the study is foundations with stepped base. To confirm the efficiency of these foundations, we conducted three different experiments: digital modelling, laboratory tests and full-scale experiment. First, the foundations were compared in terms of absolute settlement. In each of the experiments, the foundation with a stepped base was more efficient than its flat-base analogue (by about 30 %). During the full-scale experiment, at a final pressure under the foundation base of 18 t/m², the foundation with flat base settled by 70.67 mm, while the foundation with stepped base settled by 49.32 mm. The experiment confirmed the results of the previous experiments: the foundation with a stepped base showed a substantially smaller settlement than the flat base analogue. In future studies, we plan to investigate the operation of strip foundations with stepped base in more detail, to determine the internal forces appearing in the body of the foundations, and to define the need of reinforcement for foundations with stepped base. 

Experimental studies of processes in soil foundations under load show that soils exhibit viscoelastic properties. The article presents the method for determining the mechanical characteristics of viscoelastic soil. One of the functions, for example, the soil creep function, is obtained from the experimental data of testing a sample for creep. Next, the soil relaxation function was determined using the numerical-analytical method of broken lines. The representation of the creep function in the form of a broken line made it possible to obtain the relaxation function (the inverse function to the creep function in Laplace – Carson images) as a solution of the viscoelasticity problem. Based on the known image of the desired original of the relaxation function in the form of a broken line, a transition from the image to the original was made using the broken line method, which is reduced to a system of linear algebraic equations regarding the desired parameters of the relaxation function. To determine the relaxation function using the proposed method, there is no need to experiment with a soil sample for relaxation. This saves on laboratory experiments. The proposed algorithm is of interest when designing construction projects on weak soil foundations, taking into account the viscoelastic properties of the soil. 

The existing urban trends give new demands on the transport infrastructure of modern cities. Urban development planning should be based on representative traffic information. To reduce the resource costs of network research of traffic flows, we chose the method of remote sensing of traffic by criteria of area and configuration of the streetroad network of the urbane territory with the use of modern satellite systems. The most suitable satellites for this purpose in Russia are Resurs-P and Kanopus-B, while the best satellites abroad in terms of image quality and regularity of resource updates are The Landsat Programme and Maxar (USA). We set, that the spatial resolution of satellite images and the scale of the image to be interpreted are correlated with the technical capabilities of satellite systems; the critical spatial resolution of 1/14.8 m/mm is achieved at a scale of 1:450. The authors developed an algorithm for selecting a rational method of remote sensing of traffic for different spatial urban structures at micro-, meso- and macro-levels and considered it on the example of 14 urban Russian and foreign agglomerations. The article presents a feasibility study of remote sensing application based on the "cost per unit of accuracy" criterion. Its values ranged from 0.08 to 1393.94 thousand rubles depending on the selected monitoring method and the area of spatial structures of the studied objects. The satellite remote sensing method was found to be a priority in terms of cost per unit of accuracy. Taking into account the obtained data, we plan to create a software product for automation of decoding algorithms for determining traffic parameters. 

Burning fuel in large quantities when using hot water boilers leads to losses, which reduces the energy conversion efficiency of the boiler. Therefore, there were mainly small energysaving stoves designed to burn fuel. The author proposed to use a small boiler with a firebox with a vertical grate. A small boiler with an adjustable grate water heater with a capacity of 50 kW was installed in the boarding school building. Combustion of any fuel in such a furnace had following results: a) the productivity of the boiler unit had been increased to 79–81 %; b) heat loss reduced by 2 times and harmful emissions into the atmosphere in 1.5 once. The costs of providing thermal energy compared to other operating boiler houses amounted to 14 400 somoni (1 200 dollars). This is 18 % less than the costs of the previous heating season without using the proposed boiler. The efficiency of  heating processes in the boiler was assessed during one heating season.

The resource intensity of biological wastewater treatment is reduced by increasing the energy efficiency of the pneumatic aeration systems used in the aeration tank. Modernisation of the aeration process is possible with the development of an adequate mathematical model describing the process of mass transfer from air bubble to water the oxygen required for biological oxidation of wastewater pollutants. The analysis of the LewisWhitman two-film theory, Higbee's penetration theory, and P. W. Dankwerts' theory of deformed bubble surface renewal describing the process of mass transfer of air oxygen into water showed the peculiarities of their application to gas-liquid systems. The factor of renewal of deformed surface of air bubbles is of great importance for describing the processes of mass transfer of air oxygen to water when using pneumatic aeration system in aeration tanks. In turbulent flow at continuous renewal of interfacial surface created by air bubbles, there is intensification of mass transfer process due to turbulent diffusion, which is reflected in calculated mathematical  dependences. The use of mathematical dependences determining the rate of mass transfer of air oxygen to water through the deformable surface of bubbles formed in the aeration volume of the aeration tank will make it possible to take into account the change in their shape. This will increase the accuracy of determining the values of technological characteristics of pneumatic aeration systems. 

When designing and reconstructing engineering networks of urban infrastructure, design organizations use a set of classical formulas for hydraulic calculation of pipelines. They don’t take into account changes in hydraulic potential during operation, and it leads to significant errors. This justifies the need to develop and refine reference manuals for hydraulic calculation of worn-out metal water supply, sewerage and heating networks of urban infrastructure. A specific example graphically demonstrates the influence of the thickness of the layer of internal deposits on the accuracy of the hydraulic calculation of pipes, i.e. on the determination of the parameters of their hydraulic potential. Based on the proposed methods of hydraulic calculation of pipes, we proved the relevance of revise the special reference manuals with taking into account actual changes in the values of hydraulic characteristics of metal pipelines in the process of their operation, in particular, the value of the coefficient of hydraulic efficiency of the pipeline.

Article discusses the development of electric scooter short-term rental services and their impact on the structure of the mobility of the urban population based on macrosimulation results. The purpose of the study is to assess changes in the mobility structure of the population of a large city, in witch the transport that provides regular passenger transportation on paths isolated from motor roads is absent, with the development of bicycle lanes and changes in tariffs for short-term rental of electric scooters. The study found that when the cost of  renting an electric scooter would decrease and the length of bicycle lanes would increase, the number of electric scooter users would increase and the number and proportion of journeys made by individual and public transport would decrease. The cost of renting electric scooters also affects the average travelling distance and therefore the business model of the service. Changing the cost of renting electric scooters is one way to manage the mobility of city dwellers. This could change the loading of the urban street and road network and public transport.

The work deals with the transportation of cargo in small batches in an urban environment. It was found that the weekly workload of truck drivers is not always evenly distributed. This is a prerequisite for dissatisfaction among them, as well as a reason for making mistakes or the occurrence of health problems. A partial integer nonlinear mathematical model is proposed to solve the problem. The solution of the task allows the difference between the driver who has worked the longest and the one who has worked the least to be minimal and the workload of the drivers even. We offer two possible solutions of this task (the example is based on a real situation from practice). In the first case it is the rotation principle, when three interchangeable workers working three days on three different activities. In the second case, seven workers performing six activities in one week, it is precisely determined which worker must perform activities. As a result of the calculations, the option, where the difference between the minimum and maximum time is 1.7 hours for the five working days, because it varies from 33.7 hours to 35.4 hours. In this variant, the rotation principle can also be applied in order for workers to be loaded equally. These options do not exclude the search for other solutions satisfying the problem. 

To remove stones, bushes, trees from the right-of-way of the future road it is advisable to use machines with bulldozer equipment. Theoretical basis for excavation has been considered in detail, however, based on it, it is difficult to identify and compare the partial energy costs of the impact on the ground by the elements of equipment. Without knowing the value of partial energy consumption during the operation of each element of the work tool, it is impossible to improve it in a reasonable way. The purpose of the proposed theoretical study is a detailed analysis of the interaction of the soil and the knife of the bulldozer blade for the subsequent improvement of bulldozer equipment. The object of the study is the process of interaction between the soil and the knife. In the proposed scheme, soil cutting is carried out with micro-shiftings. Depending on soil  properties and machine velocity, deformations of pseudodisplacement, volume compression, crumpling will predominate in the soil. To determine the force required for crumpling, compression and pseudodisplacement of the soil in a sloping surface, we use the conditional generalized limit of soil crumpling strength. After determining, the force required for pseudo-displacement the soil in a sloping surface, we identify the energy consumption for the initial crumpling and pseudo-displacement of one cubic meter of soil. Then we determine the primary shear strength of the soil by edge of the bulldozer knife and the corresponding energy consumption; calculate the total energy costs and power to move the bulldozer knife. Based on the developed methodology, has been determined the energy consumption for primary crumpling and pseudo-displacement of one cubic meter of soil, for shifting the soil in the longitudinalvertical plane by the knife edge, the total energy consumption, power to move the knife of the bulldozer blade at different depths. The corresponding functions are constructed and approximated. Calculation of energy consumption for moving the bulldozer knife will allow to determine the total energy  consumption in order to upgrade the bulldozer equipment for reducing the costs in the future.