69439 2658-5553 38 2 38 2026 1-60

RAR RUS 3801-3801 H-9967-2013 16412815600 0000-0002-8588-3871 Moscow Power Engineering Institute Kirsanov Mikhail Nikolaevich mpei2004@yandex.ru

Moscow, Russian Federation

Model of a spatial cantilever truss and formulas for calculating its deformations The object of research is a spatial lattice statically determinate regular cantilever truss formed by connecting eight plane trusses. The truss is loaded at its nodes. The longitudinal stiffness of the bars is assumed to be equal. Formulas are derived for the dependence of the truss end deflection on its dimensions and the number of panels. Method. The forces in the bars are found in analytical form using computer mathematics methods by solving a system of algebraic equations. The Maxwell - Mohr formula is used. Generalization of the solutions to the case of an arbitrary number of panels is performed by induction. Results. The resulting formulas for the deflections have the form of polynomials in the number of panels. Formulas are derived for the forces in individual, most critical bars. Asymptotic forms of the solutions are found. 10.57728/ALF.38.1 69 Space truss Maxwell-Mohr formula Induction Maple Analytical solution Deflection Asymptotics https://alfabuild.spbstu.ru/article/2026.38.1/ 3801.pdf

RAR RUS 3802-3802 Peter the Great St. Petersburg Polytechnic University Zimin Sergey Sergeevich zimin_sergei@mail.ru

St. Petersburg, Russia

Orlovich Roman Boleslavovich Dimitrieva Sofia Olegovna Zimina Elena Andreevna Influence of backfilling of masonry vault grooves on their load-bearing capacity In static calculations of stone vaults, backfill is usually considered only as a gravitational load, and its actual interaction with the vault structure is often not taken into account. The object of research is the stress state of stone vaults. The influence of backfill on the load-bearing capacity of stone vaults is analyzed. Methods. A numerical analysis was conducted using the finite element method for vaults with a span of 8.0 m and a thickness of 0.25 m. Two materials for backfilling were considered: sand (E = 120 MPa, density 1500 kg/m³) and expanded clay (E = 15 MPa, density 250 kg/m³). The ratio of the vault height to the span f/L varied from 0.1 to 0.5. Two calculation schemes were compared: taking into account the interaction of the vault with the backfill and without it. Results. It has been found that the inclusion of backfill in the design model reduces the tensile stresses in the vault. The positive effect increases with the ratio of the vault height to the span and is more pronounced for cylindrical vaults than for cross vaults. Sand backfill provides a more significant reduction in stresses due to its higher stiffness, but it also increases the overall load on the vault. The share of the horizontal распорной нагрузки H, perceived by the backfill, reaches 43% for sand and 37% for expanded clay in semicircular vaults (f/L = 0.5). Conclusions. To reduce the static load, it is recommended to use lightweight backfill materials (such as expanded clay), while maintaining a positive interaction with the vault. The effectiveness of lightweight backfill can be improved by using layer-by-layer consolidation with cement mortar or polymer composite reinforcement. ***ARTICLE IN PRESS*** 10.57728/ALF.38.2 69 Cylindrical vaults Cross vaults Filling of vault cavities Stressed state of vaults Masonry structures Vaulted https://alfabuild.spbstu.ru/article/2026.38.2/ 3802.pdf

RAR RUS 3803-3803 H-9967-2013 16412815600 0000-0002-8588-3871 Moscow Power Engineering Institute Kirsanov Mikhail Nikolaevich mpei2004@yandex.ru

Moscow, Russian Federation

The first natural frequency and deflection of a two-hinged truss arch The object of research is a statically determinate model of a planar, regular, arched truss on two fixed, hinged supports. Using the induction method in a computer mathematics system, calculation formulas for the structure's deflection under a uniform vertical nodal load on the lower or upper chord are derived. An approximate analytical dependence of the truss's first natural frequency of oscillation on the number of panels is found. The forces in the rods are calculated for an arbitrary number of panels. Method. The truss's inertial properties are modeled using concentrated masses at the nodes. The truss's natural frequency of oscillation is calculated using the Dunkerley method and its simplified version. Vertical node oscillations are assumed. Results. A comparison of the analytical calculations with numerical results, performed taking into account all degrees of freedom of vertical mass oscillations, shows good agreement between the methods. 10.57728/ALF.38.3 69 Arched truss Fundamental frequency Induction Deflection Maple Dunkerley method https://alfabuild.spbstu.ru/article/2026.38.3/ 3803.pdf

REV RUS 3804-3804 0009-0006-9047-9386 Khraponova Liudmila Vladimirovna Brackets for ventilated façades: Material-structural parameters, mechanical-thermal characteristics, and operational reliability. A review The object of research is bracket systems in ventilated façade assemblies, which serve as critical load-bearing and thermal-transfer elements that directly govern the energy performance and service life of building envelopes. Method. A systematic review and synthesis of experimental, numerical, and bibliometric data from recent publications quantified dependencies between material selection, geometric configuration, mechanical performance, and thermal behaviour under static, dynamic, and climatic loads. Results. The analysis establishes quantified relationships between bracket parameters and façade performance. Steel and aluminium brackets provide high load-bearing capacity (60–140 kg/point) but generate significant point thermal bridges . Hybrid aluminium-polyamide and FRP systems reduce , decreasing annual building heat losses by 8-12%. Geometric optimisation, including console shortening and perforation, increases thermal resistance by 8-40%, while doubling the mounting spacing cuts thermal losses by 18% but requires compensatory anchoring reinforcement because stress increases by 25%. Long-term exposure to 5,000 cyclic loads reduces secant stiffness by 10-15%, and combined UV-moisture degradation diminishes polyamide insert strength by 15-20% over a decade. FEM-based topology optimisation reduces bracket mass by 25-30% without compromising structural integrity. Critical gaps in standardised testing for hybrid fatigue, fire safety, and long-term polymer durability are identified, providing a scientific basis for next-generation, digitally optimised, and energy-efficient façade fastening systems. 10.57728/ALF.38.4 69 Ventilated façade systems Brackets Thermal bridges Load-bearing capacity Hybrid composite materials Thermally broken connectors Energy efficiency of building envelopes https://alfabuild.spbstu.ru/article/2026.38.4/ 3804.pdf