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The article discusses the possibilities of optimizing the size of elements of reinforced concrete ceilings along. The optimization of the overlap consists in finding such parameters of the reinforced concrete slab, profiled flooring and steel beams, in which their strength is fully used. For ceilings with steel beams included, the dimensions of the sections of the elements and their strength characteristics are determined by the requirements of the limit states of the second group (deflections), and the calculation of the forces in the slab and beams and strength calculations are performed taking into account the geometric and strength characteristics established from the calculation of deformations. To clarify the features of the calculation and verification of the main provisions, a numerical experiment was carried out, where the center cell of the steel concrete slab along metal rolling beams was selected as the object of study. Formulas are obtained for determining the forces using predetermined dimensions of the components of the overlap based on satisfying the requirements of the 2 groups of limit states. These studies can serve as a basis for further research on the search for optimal parameters of complex floors.

In the article features of designing of reinforced concrete floors on the profiled flooring, leaning against steel I-beams are considered. Specific features of calculating the strength of composite slabs in accordance with JV 35.13330.2011 “Bridges and pipes” and SP 266.1325800.2016 “Structural concrete structures. Design rules”. A method for determining the forces based on the real ratio of the rigidity of the overlap elements is also considered. The analysis of the results of the numerical experiment made it possible to establish the optimum coefficients of the use of materials that can be used in the design of combined overlaps.

АННОТАцИЯ. Рассматривается влияние преднапряженной высокопрочной арматуры без сцепления с бетоном и ее расположения на прочность плиты безбалочного перекрытия. Целью исследования является установление уровня влияния преднапряженной арматуры без сцепления с бетоном и ее расположения на прочность плиты монолитного безбалочного перекрытия, а также сравнение результатов по напряжениям канатов в плитах с контурным и диагональным расположением преднапрягаемой арматуры. Форма расположения каната представлена частью параболы, проходящей через точки опоры каната. На опоре вертикальная и горизонтальная составляющая реакции определяются продольным усилием в канате и углом выхода ванты. Исследовались плиты монолитного безбалочного перекрытия 9 × 9 м в двух вариантах: с диагональной и контурной напрягаемой арматурой. Вычислены приращения напряжений в канатах и итоговые значения при различных уровнях преднапряжения и прогибов. Применение высокопрочных предварительно напряженных канатов без сцепления с бетоном в качестве дополнительной рабочей арматуры уменьшает прогибы плиты перекрытия и снижает расход обычной арматуры. Результаты свидетельствует об относительном снижении эффективности использования прочности канатов при повышении начального уровня преднапряжения. С точки зрения обеспечения несущей способности, контурное расположение канатов предпочтительнее из-за более полного использования прочности высокопрочной арматуры. Для удовлетворения требований первой группы предельных состояний установление уровня преднапряжения канатов должно производиться с учетом возможного достижения в высокопрочной арматуре расчетных напряжений.

Introduction. Objective and regular students’ knowledge monitoring in technical subjects can be implemented by means of special tests allowing for the required mastering level of the matter and the reliable consolidation of the acquired knowledge. Various aspects of the application of tests in the academic activity were considered. Materials and methods. Tests used in practical studies should meet specific requirements, such as: validity, definiteness, simplicity, unambiguity, reliability. The identification of mastering levels makes it possible to “troubleshoot” and to improve the academic activity and the mastering degree of the competences by the students. Based on the assessment of the studying pattern of the forthcoming activity, one could point out four mastering levels of the subject matter. Level I tests include recognition, discrimination and classification. Level II tests monitor the mastering of the subject in the level of “reproduction” allowing for retrieval of information from the memory and its analysis, for routine assignment solutions. Level III tests impose special assignments challenging a student with quests for which no ready algorithms are catered, whereas the solutions found lead to obtaining of subjectively new information. Level IV tests reveal students’ capability to take decisions in new problematic situations, the solutions found, being a result of creative activity, are followed by obtaining of objectively new information. Results. To establish an efficient system of monitoring tests in a certain subject, a number of basic prerequisites is required, such as a data base, a sample group of with the required number of assignments, at least 30 and maximum 70, a time limit in accordance with the required labor intensity, assessment of the assignments and its criteria, the output of the results. Conclusions. If there is a required number of computers of at least one PC per two students, correctly arranged computer testing considerably reduces time demand of a monitoring event, increases the responsibility and the progress of the students, guarantees the objectiveness of the knowledge monitoring and helps to avoid conflicts.