AlfaBuild

RAR RUS 2801-2801 0009-0001-6785-1366 Krupenin Fedor Romanovich theoharicot@yandex.ru Factors influencing the use of self-lifting formwork in the field of high-rise construction The object of research is the National Space Center, a high-rise building under construction in Moscow. Method. The method used involves objective observations to determine the impact of various factors associated with the use of self-lifting formwork on the construction speed of high-rise buildings. Furthermore, the study implements optimized construction methods to reduce the influence of these factors on the building process. Results. The results obtained from this research provide insights and solutions for reducing the impact of the investigated factors on the erection of high-rise structures. Understanding these factors will help to consider important nuances during the construction of future high-rise projects using self-lifting formwork techniques. 10.57728/ALF.28.1 69 Formwork Self-climbing formwork Construction Load-bearing structure High-rise construction Modern construction Management in construction Construction Management Optimization in construction https://alfabuild.spbstu.ru/article/2023.28.1/ 2801.pdf

RAR RUS 2802-2802 ABD-9922-2021 0000-0002-9330-2221 Peter the Great St.Petersburg Polytechnic University Iakovlev Nikita Artemovich nik_yakovlev@list.ru

Russia, 195251, St.Petersburg, Polytechnicheskaya, 29

O-6995-2019 6508103761 0000-0002-1196-8004 Peter the Great St. Petersburg Polytechnic University Vatin Nikolai Ivanovich vatin@mail.ru

Saint-Petersburg, Russian Federation

0009-0002-9463-6108 Volkov Evgenii Vitalievich 0009-0003-0250-523X Vasilev Pavel Alexandrovich 0009-0003-9226-7211 Beliaev Aleksei Vladimirovich Effectiveness of replacing steel reinforcement of concrete floor slab with composite reinforcement The object of research is composite polymer reinforcement, specifically fiberglass rebar. This material has advantages over traditional rebar. Corrosion, for example, is the main problem of steel reinforcement, while composite rebar is resistant to it. Other merits and demerits of composite reinforcement are also considered. Monolithic concrete structures reinforced with composite rebars have increased durability because they are resistant to water or aggressive media. This is relevant, for example, for building foundations and monolithic structures of underground parking. It can be assumed that composite rebars are economically more beneficial than steel ones due to their physical and mechanical properties. The purpose of the study is to estimate the economic efficiency of using composite polymer reinforcement in the monolithic floor of the underground parking instead of steel reinforcement. Method. The research method used in the work is analytical calculation of the required quantity of both types of reinforcement for monolithic floor slab under given loads and their comparison. Results. It is determined that the replacement of steel reinforcement with FRP rebar reduces the cost of materials by 33%. Moreover, other factors that reduce costs at construction sites when composite reinforcement is used are also given. 10.57728/ALF.28.2 69 Fiber-reinforced polymer bars Fiberglass Steel rebar Cost reduction Monolithic ground floor Underground parking Concrete construction https://alfabuild.spbstu.ru/article/2023.28.2/ 2802.pdf

RAR RUS 2803-2803 0009-0007-5506-617X Al-Eqabi Haqi Abbood 0000-0002-6181-2817 Prokopov Albert Yurievich Using recycled crushed concrete columns to stabilize fully saturated silty clay soil The object of the study is the improvement of fully saturated silty clay soil using columns of recycled crushed concrete. ASTM D 2166 - Standard Test Procedure for Unconfined Compressive Strength of Cohesive Soil is used to apply the axial load. This work aims to examine how recycled crushed concrete affects settlement control and bearing capacity by 38%, increasing the initial soil state and reducing swelling from 14.75% to 5.66% in 7 days. The research also examined the variation in subgrade modulus and the cause of a shallow circular footing's failure on the soil where silt clay layer soil had been substituted with recycled broken concrete. The results demonstrated that combining a partly replaced column of silty clay soil and a column of recycled crushed concrete significantly preload-bearing capability. The approach may drastically alter the footing's stress displacement curve when resting on silty clay soil, reduce settlement, swelling, and shrinkage, and make the replacement soil block within the container act as a deep foundation. Consequently, a foundation supported by silty clay may change its bearing capacity failure mechanism at the top of a column constructed of recycled crushed concrete from exclusive settling to general bearing capacity failure—the use of fills with shattered concrete, whether natural or artificial, is growing. Hence, research into this material's bearing and deformation properties is essential for application areas such as road construction, soil replenishment, and embankments. 10.57728/ALF.28.3 69 Circular footings Expansive saturated soil Crushed concrete columns Soil settlement https://alfabuild.spbstu.ru/article/2023.28.3/ 2803.pdf

RAR RUS 2804-2804 0000-0002-3142-6018 Kirsanova Tatiana Aleksandrovna 89094001052@mail.ru 0009-0000-1328-8515 Shchetenkov Alexey Viktorovich 0009-0006-0769-1854 Yakupov Sergey Zakievich 0000-0002-7422-5494 Peter the Great St. Petersburg Polytechnic University Vafaeva KHristina Maksudovna vafaeva.khm@gmail.com

St. Petersburg, Russian Federation

0000-0003-3389-7742 Peter the Great St. Petersburg Polytechnic University Shinkareva Maria Konstantinovna shinkareva_mk@spbstu.ru Variants of pipeline assemblies made of composite materials and their connections and technological units The object of research is a polymer composite pipeline with connections and technological nodes. Method. During the research, methods of system analysis, methods of expert assessments, risk theory, comparative method, method of generalization, abstraction, induction, and deduction were used. Results. The analysis of theoretical sources, tests, scientific publications and regulatory documents was carried out, as a result of which the criteria for the characteristics of polymer composite networks were established, providing conditions for the economically and practically profitable use of polymer composite networks based on the project of a high-rise construction object, as a result of which the criteria for the characteristics of the object were established, providing conditions for the economically profitable use of self-lifting formwork, and a financial and economic model to justify the investment in this project has been invested. The pipes can operate at an operating pressure from a vacuum of 0.01-0.35 MPa and at an operating temperature from -269 to +150°C. The polymer composite material must contain a binder in the range of 28-36%, and the density of the binder varies from 1.75 to 1.85 g/cm3. 10.57728/ALF.28.4 69 Polymer pipelines Composite pipelines Polymer composite material Connections in polymer pipes Connections in composite pipes Technological polymer nodes Composite polymer nodes https://alfabuild.spbstu.ru/article/2023.28.4/ 2804.pdf

RAR RUS 2805-2805 H-9967-2013 16412815600 0000-0002-8588-3871 Moscow Power Engineering Institute Kirsanov Mikhail Nikolaevich mpei2004@yandex.ru

Moscow, Russian Federation

0009-0003-7831-3402 Pakhomov Vasiliy Aleksandrovich The lower limit of natural frequency and the oscillation spectrum of a planar truss The point masses at the nodes are employed to model the inertial characteristics of a flat truss model with articulated supports. Each mass has two degrees of freedom. The statically determined structure's stiffness matrix is ascertained using the Maxwell-More equation. Implementing the secant knots technique within the Maple computer mathematical system is employed to derive the forces exerted on the anchor rods through analytical means. The minimum value for the first natural frequency is determined via the employment of the Dunkerley method. Individual solutions for trusses with a sequentially increasing number of panels are generalized to the arbitrary case by the double induction method on the number of panels in the beam and the number of panels in the supporting side parts of the truss. The analytical correlation is juxtaposed with the numerical resolution of the problem on the spectrum of natural frequencies of the structure. As the quantity of panels is augmented, there is a corresponding enhancement in the precision of the analytical evaluation, as demonstrated in empirical findings. 10.57728/ALF.28.5 69 Truss Natural oscillation frequency Induction Maple Planar truss Dunkerley method https://alfabuild.spbstu.ru/article/2023.28.5/ 2805.pdf