33407 2304-6295 2 122 2026 1-60

RAR RUS 12201-12201 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

Reinforced concrete precast beam with a stepped joint The object of research is a precast reinforced concrete beam with a stepped joint strengthened by composite reinforcement bars. Method. The study employed an experimental–numerical approach. Four beam specimens were prepared, including one monolithic control specimen and three composite specimens consisting of two reinforced concrete parts connected by a stepped joint. The joint zone was reinforced with composite rods installed in preformed holes and grooves. Static loading tests were carried out using a P-50 hydraulic press to determine the load-bearing capacity, deformation response, and failure pattern of the beams. In parallel, a finite element model was developed in the LIRA-SAPR software package with consideration of the physical nonlinearity of concrete. The numerical model was calibrated and compared with the experimental results. Results. The experimental study showed that the reinforced concrete precast beam retained its load-bearing capacity up to an ultimate load of approximately 25 kN. Failure occurred predominantly in the stepped joint zone and was accompanied by crack development, local concrete damage, and loss of stiffness. Numerical analysis reproduced the general deformation pattern and stress concentration in the joint region; however, the calculated ultimate load exceeded the experimental one by approximately 1.8 times. The discrepancy is attributed to material heterogeneity, technological imperfections in specimen fabrication, and the simplified representation of the joint behavior in the numerical model. The results confirm the feasibility of using stepped composite joints in precast reinforced concrete beams, while indicating the need for further optimization of anchorage depth and reinforcement layout to improve structural performance. 10.4123/CUBS.122.1 69 Precast concrete beam Quickly erected connection Reinforced beam Composite rods https://unistroy.spbstu.ru/article/2026.122.1/ 12201.pdf

RAR RUS 12202-12202 0000-0001-7562-5652 Peoples Friendship University of Russia Obeid Mahmoud Abdelsalam Aref mahmoud.obeid@yandex.com 0000-0002-4323-9818 Peoples Friendship University of Russia Abu-Mahadi Mohammed Ibrahim abu-makhadi-mi@rudn.ru Markovich Alexey Semenovich Qais Qais Abdurrahman Ali 0009-0006-3764-1022 Peoples Friendship University of Russia Nasrat Nasratullah Abdul Ghafoor nasratullahnasrat609@yahoo.com Pirot Omed Mohammed Abebe Temesgen Ayalew Jazzan Muhannad Kveng Phearom Concrete mix optimized with glass powders The object of the research is the use of glass powder and ultrafine glass powder as sustainable alternatives to natural sand in M25-grade concrete, addressing the environmental and resource challenges caused by sand depletion in Jordan. Method. The study examines the effects of replacing fine aggregate with glass powder (10% to 20%) on concrete's compressive strength, using the water absorption method. The concrete mixes were designed following ACI 211.1 guidelines, with materials hand-mixed and each component precisely weighed. The mix was placed in cubic molds, compacted, and cured in water for 28 days. A total of 24 specimens were prepared and tested for compressive strength after 28 days using a universal testing machine C040PN. Results. Incorporating 10% glass powder as a cement replacement optimizes the mechanical performance of concrete, achieving a 28-day compressive strength of 61.98 MPa—10.83% of the control mix strength (55.92 MPa). This mix also demonstrates an ultrasonic pulse velocity of 5.51 km/s, a slump of 60 mm, and a modulus of elasticity of 37 GPa. These results confirm that using 10% glass powder enhances or maintains key structural properties while promoting the sustainable reuse of waste glass—offering a viable, eco-friendly solution for the construction industry in Jordan without compromising performance. 10.4123/CUBS.122.2 69 Glass powder Ultrafine glass powder Fine aggregate replacement Concrete mix optimization Waste glass Durability Superplasticizer Jordan SCAD++ https://unistroy.spbstu.ru/article/2026.122.2/ 12202.pdf

RAR RUS 12203-12203 Gusev Konstantin Vladimirovich gusev2.kv@gmail.com AAH-3368-2019 56091980300 0000-0003-3850-424X Peter the Great St. Petersburg Polytechnic University Lalin Vladimir Vladimirovich vllalin@yandex.ru

St. Petersburg, Russian Federation

AAE-3259-2020 56296687300 0000-0002-2299-3096 Peter the Great St. Petersburg Polytechnic University Rybakov Vladimir Alexandrovich fishermanoff@mail.ru

St. Petersburg, Russian Federation

Bearing capacity of bonded connection in facade structures with vertically bonded cladding The object of research is a structural silicone adhesive sealant. This work aims to identify the factors affecting the stress–strain state of the bonded joint in facade structures with vertically bonded cladding using numerical and analytical calculation methods. Method. As part of the conducted study, a numerical assessment of the performance of the bonded connection was carried out. Four computational models of the bonded connection were developed, each with a different level of detail in simulating the ventilated façade system with vertically bonded cladding. The shear and normal stresses obtained from the numerical simulations were compared with the values specified in accordance with the requirements of the regulatory document ETAG 002. Results. Numerical analyses accounting for the facade substructure show that the inclusion of hanger connections, brackets, and guide profiles has a significant impact (up to 15 %) on the magnitude and distribution pattern of shear stresses within the bonded connection under self‑weight loading. It is proposed that the load‑bearing capacity of the bonded connection in facade systems with vertically bonded cladding under wind pressure be evaluated using a numerical method based on a detailed model that considers the stiffness and arrangement of hanger connections and brackets. This recommendation is made because the structural configuration and the placement of brackets exert a substantial influence (up to 40 %) on the stress–strain state of the bonded connection. 10.4123/CUBS.122.3 69 Facade structures Adhesive joint Direct vertical bonding Silicone adhesive sealant Stress–strain state Numerical modeling https://unistroy.spbstu.ru/article/2026.122.3/ 12203.pdf