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  • Analysis of methods of calculation of girderless floors on breakdown

    In article results of the analysis of method of calculation of flat plates of girderless floors are considered on breakdown according to the Russian and foreign design codes are considered. The analysis of the received results demonstrates that in the considered calculation procedures on breakdown similar settlement models are used and identical power factors are considered. Namely the pressing-through effort and the bending moments operating in two planes. Taking note of the moments in various techniques is carried out in two ways. The first way – tangent tension is entered into settlement model. And each technique offers the form of an epyura of tangent tension. The second way – introduction to a condition of durability of the empirical coefficient considering influence of the bending moments. Approach to purpose of geometrical parameters of a settlement (critical) contour is not identical. Contours of different techniques differ in a form and the sizes. And the difference of the sizes is very considerable. It is established that work of knot of interface of girderless flag with a column is studied yet not fully and additional researches on generalization of calculation procedures are required.

    Keywords: reinforced concrete, girderless floor, breakdown, working height of section, transversal armature, pyramid of breakdown

  • Investigation of the influence of the deviations of the position of the working armature from the project on the bearing strength of the overlap

    In the article results of the analysis of analytical dependences and results of the computing experiment executed in Lyr-CAD environment are considered. The purpose of the performed work is a quantitative assessment of the reduction in strength of beams of monolithic reinforced concrete overlappings caused by errors made during the performance of reinforcement work. In particular, an increase in the thickness of the protective layer of concrete and the consequent reduction in the working height of the section are considered. The data analyzed for both reference and span cross sections are analyzed. In total, four series of samples were selected, differing in the class of concrete (B15, B20, B25 and B30). Each series consisted of 9 samples having different working height sections in the reference and span sections. The working height of the section varied from 5 to 22%. The finite element model was created in the LIRA-CAD environment. In the course of the analysis, the effect of changing the working height of the section on the area of ​​the reference and passing reinforcement, selected for strength, was investigated.

    Keywords: It is established that the degree of influence of the deviations of the position of the reinforcement from the design in the reference sections and in the span is different. The greatest danger is represented by the support sections, that is, the overlapp