33407 2304-6295 1 110 2024 1-60

RAR RUS 11001-11001 Sivakov Ivan Anatolyevich i.a.sivakov@gmail.com 0000-0002-6155-060X Peter the Great St.Petersburg Polytechnic University Shabunina Daria Evgenievna shabunina_de@spbstu.ru

St.Petersburg, Russian Federation

0000-0002-2410-5216 Chizhikov Vladimir Petrovich vovach1952@gmail.com Capacity of metro station elements as a function of human traffic density The object of research is turnstiles and escalators of subway stations. The work aims to obtain dependence of turnstile and escalator capacity on human traffic density and to determine the maximum values of the capacity of escalators and turnstiles in the operational mode of the station. Method. To obtain the values of throughput capacities, experimental studies were conducted on observations of incoming passengers at loaded stations of St. Petersburg subway during the peak hours of station The experimental data were processed using the least squares method (second-order polynomial model). Results. Mathematical dependences of turnstiles and escalators capacity on human traffic density were obtained. It was established that the maximum escalator capacity for ascent in the operational mode of the station is 5500 people/hour, for descent - 4200 people/hour. The maximum turnstile capacity at the operational mode of the station is 1430 people/hour. It was found that the Russian regulatory base overestimates the escalator capacity by 33.5% and underestimates the turnstile capacity by 43%. 10.4123/CUBS.110.1 69 Escalator Turnstile Capacity Experimental study Subway Passenger flow Density of human traffic https://unistroy.spbstu.ru/article/2024.110.1/ 11001.pdf

RAR RUS 11002-11002 Ignatyev Aleksey Aleksandrovich ignatievaa@rosdornii.ru Formation of the pavement frame from a granular redesign by compaction The compaction of hot asphalt-concrete mixtures has several disadvantages. In turn, granular redesigns are deprived of these disadvantages but are little studied. The object of research is granular redesigns. This work aims to study the peculiarities of compaction of granular redesigns in the temperature range from 20 °C to 120 °C. The results of theoretical and experimental studies are presented, reflecting the peculiarities of forming the framework of the material obtained from granular redesigns using a known technological technique - compaction. Methods. Experimental studies were carried out using the traditional Russian Federation equipment for testing asphalt concrete mixtures. The uniaxial compressive strength of the samples at 20°C, water saturation, and water resistance after prolonged water saturation were measured. Results. While studying the compaction characteristics of granular redesigns (materials representing crushed stone with a shell of asphalt binder), it was found that overmixes are more effectively compacted than traditional asphalt concrete mixtures at significantly lower temperatures. The overmixes' effective compaction temperatures range from 20 °C to 120 °C. The established effect makes it possible to reduce the anthropogenic load on nature and reduce the volume of harmful emissions into the atmosphere due to the reduction of paving temperature. Compaction of the granular redesigns at the temperature of 80 °С, which is 40 °С less than the traditional temperatures of hot mixes compaction, allowed to obtain increased indices of strength (more than 3.00 MPa) and water resistance (water resistance coefficient Kv not less than 0.85). These results are in demand for the road industry and can be used to obtain new, more load-bearing, and durable road surfaces. 10.4123/CUBS.110.2 69 Asphalt concrete Pavement Compaction Granular mixtures Conversion Compaction temperature https://unistroy.spbstu.ru/article/2024.110.2/ 11002.pdf

RAR RUS 11003-11003 0000-0002-6848-0974 Moscow Power Engineering Institute Luong Cong Luan luongcongluan96@gmail.com

Moscow, Russian Federation

H-9967-2013 16412815600 0000-0002-8588-3871 National Research University Moscow Power Engineering Institute Kirsanov Mikhail Nikolaevich mpei2004@yandex.ru

Moscow, Russian Federation

Effect of truss height on the safe frequency region of a statically determined flat truss The object of research is a statically determined symmetric planar model. Assume that the truss bars have the same stiffness and cross-section and that the truss masses are evenly distributed at their nodes. Method. The Dunkerley formula and a simplified method are proposed to estimate the lowest limit of the natural vibration frequency of a truss with an arbitrary number of plates. Solving the system of linear equations determines the force in the rods, and all analytical transformations are performed in the Maple computer mathematics package. Using the Maxwell-Mohr formula, find the stiffness matrix of the structure. Results. The first natural frequency of the truss obtained by the analytical method is compared with the results of the numerical method. The frequency spectrum of the truss was analyzed, and conclusions were drawn about the frequency dependence on the size of the truss rods. 10.4123/CUBS.110.3 69 Truss Maple Natural frequency Dunkerley method Spectra of natural frequencies Simplified method Analytical solution Resonant safe range https://unistroy.spbstu.ru/article/2024.110.3/ 11003.pdf

RAR RUS 11004-11004 Pribylskaya Natalya Mikhailovna natalyapribylskaya@gmail.com Grechukhin Vladimir Alexandrovich vag_ftk@bntu.by Metal shields and method of its construction from guide pipes and basic elements The object of research is an engineering solution for the design and technology of pipe canopies used in underground structures, which lie at a relatively shallow depth below the surface, pass through soft ground, and have a small length. This paper describes a finite-element method for modeling a pipe canopy using SolidWorks. The authors analyzed the stress-strain behavior of the load-bearing structural elements of the pipe canopy. The pipe canopies prevent deformation and subsidence of the bearing layer, minimize the impact of civil engineering work on city and traffic infrastructure, and ensure building safety. Constructing underground structures using pipe canopies does not require traffic congestion on existing railroads and major roads, thus avoiding financial losses, discomfort for people, and negative impacts on aboveground buildings and structures. The main research objectives are to show that the proposed design of the pipe canopy is viable and can reduce the cost of constructing the pipe canopy by using less powerful equipment for pushing structural elements. Method. One of the key issues when installing underground transport communications is to keep the same high-altitude position (soil body), which pipe canopies can ensure. The authors studied the stress-strain behavior of the proposed pipe canopies using a computational model developed based on the finite-element method. The authors used Romberg’s method to increase the accuracy of calculating the internal forces for pushing individual structural elements of the pipe canopy. Results. The most widely used and available options for pipe canopies and presents the main reasons why they are not appropriate. The proposed design and technology of the pipe canopy keep the advantages of pipe canopies and technologies currently used while reducing the costs of constructing the pipe canopy using less powerful equipment. The calculations showed that the maximum stress sustained by some elements of the top part, namely, section-cut pipes at the points of joining the guide pipes along the U-shaped edges of the round, does not exceed the yield strength of the steel chosen. This confirms the efficiency of the proposed pipe canopy. 10.4123/CUBS.110.4 69 Underground transportation facilities Shields Make concave Overlying strata fracture Deformation and subsidence of the bearing stratum https://unistroy.spbstu.ru/article/2024.110.4/ 11004.pdf

RAR RUS 11005-11005 P-3728-2017 57194112309 0000-0001-6184-2365 Vyatka State University Tyukalov Yury Yakovlevich yutvgu@mail.ru

Kirov, Russian Federation

GMW-6276-2022 0000-0002-3884-874X Vyatka State University Ashikhmin Stanislav Eduardovich ashihminstanislav@gmail.com

Kirov, Russian Federation

Pliability of a composite rod glued into concrete The object of research is the connection of composite rods glued into concrete. The purpose of this work is to numerically study the stress-strain state of a glued composite rod under the action of a pull-out load. Method. To analyze the stress-strain state of the connection, a spatial finite element model was used. Physically nonlinear finite elements are used for specific modeling. For the calculations, a nonlinear diagram of the deformation of concrete and steel reinforcement were used, given in the regulatory documents for the design of reinforced concrete structures. Composite rods with epoxy adhesive are elastically deformed. The design scheme was modeled with spatial finite elements. Results. A numerical analysis of the stress-strain state of a glued joint was carried out using the example of a precast reinforced concrete frame. The results of structural calculations considering the compliance of the glued layer and without it were compared. The comparison results show that considering the flexibility of glued layer is not essential for the design; the maximum loads decreased by 5%. 10.4123/CUBS.110.5 69 Precast concrete elements Glued layer Composite rods Epoxy adhesive Physical nonlinearity https://unistroy.spbstu.ru/article/2024.110.5/ 11005.pdf

RAR RUS 11006-11006 Slobodchikova Nadezhda Anatolievna NSlobodchikova@rambler.ru 0009-0006-8525-9725 Peter the Great St. Petersburg Polytechnic University Bashkarev Albert Yakovlevich bashkarev@spbstu.ru

Saint Petersburg, Russian Federation

Selection of a composition of reinforced soils The object of research is reinforced soils, which are effective materials for the construction of highways. For effective practical application of reinforced soils, it is necessary to correctly select the optimal composition of reinforced soils in laboratory conditions. The qualitative characteristics are determined on reinforced soil samples after their hardening under normal conditions at the design age of 28, 56, 90, or more days. The long work duration on the composition selection makes it difficult to use these materials, especially in conditions of continental and polar climate, when the duration of the construction season is short. Method. It is proposed that microwave radiation be used to reduce the time needed to select the composition. The treatment of reinforced soil samples with microwave radiation 2,45 GHz provides strength within one hour. Powerful microwave radiation contributes to the rapid heating and destruction of the reinforced soil sample. Temperature changes and sample size must be considered when processing samples with microwave radiation humidity. Various soils selected on the territory of the Irkutsk region were used for experimental studies. Results. Comparative compressive strength tests of reinforced soil samples obtained by hardening under normal conditions and microwave radiation treatment showed similar compressive strength values. 10.4123/CUBS.110.6 69 Reinforced soil Composition selection Microwave radiation Road construction Ash and slag materials https://unistroy.spbstu.ru/article/2024.110.6/ 11006.pdf