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<article xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:ali="http://www.niso.org/schemas/ali/1.0/" article-type="research-article" dtd-version="1.2" xml:lang="en"><front><journal-meta><journal-id journal-id-type="publisher-id">Structural Mechanics of Engineering Constructions and Buildings</journal-id><journal-title-group><journal-title xml:lang="en">Structural Mechanics of Engineering Constructions and Buildings</journal-title><trans-title-group xml:lang="ru"><trans-title>Строительная механика инженерных конструкций и сооружений</trans-title></trans-title-group></journal-title-group><issn publication-format="print">1815-5235</issn><issn publication-format="electronic">2587-8700</issn><publisher><publisher-name xml:lang="en">Peoples’ Friendship University of Russia named after Patrice Lumumba (RUDN University)</publisher-name></publisher></journal-meta><article-meta><article-id pub-id-type="publisher-id">53144</article-id><article-id pub-id-type="doi">10.22363/1815-5235-2026-22-4-368-382</article-id><article-id pub-id-type="edn">LQJMYQ</article-id><article-categories><subj-group subj-group-type="toc-heading" xml:lang="en"><subject>Analytical and numerical methods of analysis of structures</subject></subj-group><subj-group subj-group-type="toc-heading" xml:lang="ru"><subject>Аналитические и численные методы расчета конструкций</subject></subj-group><subj-group subj-group-type="article-type"><subject>Research Article</subject></subj-group></article-categories><title-group><article-title xml:lang="en">Nonlinear Layered Formulation: Modeling Reinforced Concrete Semi-Precast Slabs</article-title><trans-title-group xml:lang="ru"><trans-title>Нелинейная послойная формулировка: моделирование сборно-монолитных железобетонных плит</trans-title></trans-title-group></title-group><contrib-group><contrib contrib-type="author"><contrib-id contrib-id-type="orcid">https://orcid.org/0009-0003-2819-3107</contrib-id><name-alternatives><name xml:lang="en"><surname>Mawlood</surname><given-names>Dara A.</given-names></name><name xml:lang="ru"><surname>Мавлуд</surname><given-names>Дара А.</given-names></name></name-alternatives><bio xml:lang="en"><p>master student, Department of Building Structures and Controlled Systems, Institute of Civil Engineering</p></bio><bio xml:lang="ru"><p>магистрант кафедры строительных конструкций и управляемых систем, Инженерно-строительный институт</p></bio><email>dara.mawloud@univsul.edu.iq</email><xref ref-type="aff" rid="aff1"/></contrib><contrib contrib-type="author"><contrib-id contrib-id-type="orcid">https://orcid.org/0000-0001-5271-9904</contrib-id><contrib-id contrib-id-type="spin">2779-8314</contrib-id><name-alternatives><name xml:lang="en"><surname>Koyankin</surname><given-names>Alexandr A.</given-names></name><name xml:lang="ru"><surname>Коянкин</surname><given-names>Александр Александрович</given-names></name></name-alternatives><bio xml:lang="en"><p>Candidate of Technical Sciences, Associate Professor of the Department of Building Structures and Controlled Systems, Institute of Civil Engineering</p></bio><bio xml:lang="ru"><p>кандидат технических наук, доцент кафедры строительных конструкций и управляемых систем, Инженерно-строительный институт</p></bio><email>KoyankinAA@mail.ru</email><xref ref-type="aff" rid="aff1"/></contrib></contrib-group><aff-alternatives id="aff1"><aff><institution xml:lang="en">Siberian Federal University</institution></aff><aff><institution xml:lang="ru">Сибирский федеральный университет</institution></aff></aff-alternatives><pub-date date-type="pub" iso-8601-date="2026-10-29" publication-format="electronic"><day>29</day><month>10</month><year>2026</year></pub-date><volume>22</volume><issue>4</issue><issue-title xml:lang="en">VOL 22, NO4 (2025)</issue-title><issue-title xml:lang="ru">ТОМ 22, №4 (2025)</issue-title><fpage>368</fpage><lpage>382</lpage><history><date date-type="received" iso-8601-date="2026-10-29"><day>29</day><month>10</month><year>2026</year></date></history><permissions><copyright-statement xml:lang="en">Copyright ©; 2026, Mawlood D.A., Koyankin A.A.</copyright-statement><copyright-statement xml:lang="ru">Copyright ©; 2026, Мавлуд Д.А., Коянкин А.А.</copyright-statement><copyright-year>2026</copyright-year><copyright-holder xml:lang="en">Mawlood D.A., Koyankin A.A.</copyright-holder><copyright-holder xml:lang="ru">Мавлуд Д.А., Коянкин А.А.</copyright-holder><ali:free_to_read xmlns:ali="http://www.niso.org/schemas/ali/1.0/"/><license><ali:license_ref xmlns:ali="http://www.niso.org/schemas/ali/1.0/">https://creativecommons.org/licenses/by-nc/4.0</ali:license_ref></license></permissions><self-uri xlink:href="https://journals.rudn.ru/structural-mechanics/article/view/53144">https://journals.rudn.ru/structural-mechanics/article/view/53144</self-uri><abstract xml:lang="en"><p>Semi-precast reinforced concrete slab systems enhance construction efficiency by substantially reducing on-site formwork. Construction involves two primary phases: (1) off-site fabrication of semi-precast components and (2) on-site casting of a concrete topping. The interfacial bond strength between the precast base and the cast-in-place overlay is a critical factor governing the composite system's performance. This study presents a comprehensive numerical investigation to evaluate the effect of surface treatment techniques on the flexural behavior of semi-precast RC slabs. A novel six-node triangular layered finite element approach is developed, incorporating material nonlinearity through an enhanced global-local plate formulation. The method employs a cross-sectional discretization strategy, decomposing the slab into distinct material layers where concrete and steel are modeled as discrete plate elements with individual constitutive laws. The computational framework utilizes a decoupled treatment of displacement fields and transverse stresses, facilitating accurate nodal stress evaluation via integrated constitutive models. Spatial discretization is achieved using a C ¹-continuous six-node triangular element, with governing equations derived from a partially mixed variation principle. Validation through benchmark cases demonstrates the method’s robustness, with ultimate deflection errors below 4.68% and reaching 0.5% accuracy in optimal scenarios. The proposed triangular layered finite element method achieves superior accuracy and computational efficiency compared to conventional approaches.</p></abstract><trans-abstract xml:lang="ru"><p>Системы из сборно-монолитных железобетонных плит повышают эффективность строительства за счет существенного сокращения затрат на опалубку на строительной площадке. Строительство включает в себя два основных этапа: (1) изготовление сборных элементов за пределами площадки и (2) заливка верхнего слоя из монолитного бетона на площадке. Прочность связи между сборным основанием и монолитной облицовкой является критическим фактором, определяющим эксплуатационные характеристики композитной системы. В данном исследовании представлено комплексное численное исследование для оценки влияния методов обработки поверхности на изгиб сборных железобетонных плит. Разработан новый метод расчета с шестиузловым треугольным слоистым конечным элементом, учитывающий нелинейность материала за счет усовершенствованной глобально-локальной формулировки пластины. В этом методе используется стратегия дискретизации поперечного сечения, при которой плита разбивается на отдельные слои материала, где бетон и сталь моделируются как отдельные элементы плиты с собственными определяющими соотношениями. В рамках данной методики расчета используется несвязанный подход к полям смещений и поперечных напряжений, что позволяет точно оценивать узловые напряжения с помощью интегрированных определяющих моделей. Пространственная дискретизация достигается с помощью С 1-гладкого шестиузлового треугольного элемента с основными уравнениями, полученными на основе частично смешанного вариационного принципа. Проверка с помощью контрольных примеров демонстрирует надежность метода, при этом погрешности предельных отклонений не превышают 4,68 %, а в оптимальных сценариях достигают точности 0,5 %. Предложенный метод многлослойных треугольных конечных элементов обеспечивает превосходную точность и вычислительную эффективность по сравнению с традиционными подходами.</p></trans-abstract><kwd-group xml:lang="en"><kwd>semi-precast slab</kwd><kwd>strain field</kwd><kwd>stress field</kwd><kwd>layered FE discretization</kwd><kwd>and numerical results</kwd></kwd-group><kwd-group xml:lang="ru"><kwd>сборно-монолитная плита перекрытия</kwd><kwd>поле деформаций</kwd><kwd>поле напряжений</kwd><kwd>дискретизация на многослойные конечные элементы</kwd><kwd>численные результаты</kwd></kwd-group><funding-group/></article-meta><fn-group/></front><body></body><back><ref-list><ref id="B1"><label>1.</label><mixed-citation>Tam VWY, Fung IWH, Sing MCP. et al. Best practice of prefabrication implementation in the Hong Kong public and private sectors. 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