About the authors
| First name, Middle name, Last name, Scientific degree, Scientific rank, Current position. Full and brief name of the organization, The organization address. | Radaikin O.V. – assistant E-mail: This e-mail address is being protected from spambots. You need JavaScript enabled to view it Kazan State University of Architecture and Engineering The organization address: 420043, Russia, Kazan, Zelenaya st., 1 |
| Title of the article | To improve the method of calculating the bending stiffness of reinforced concrete elements without prestressing |
| Abstract. | The article is devoted to improving the methodology of calculation of flexural reinforced concrete elements without prestressing. The carried out research focuses on studying the actual behavior of flexural reinforced concrete structures with cracks, which can lead to a decrease in material consumption. This substantiates the relevance of the work. The author has added some principles in the physical model of deformation of the considered elements, based on modern achievements of fracture mechanics and the theory of damage. This substantiates the scientific novelty of the work. Presented an improved model allows to determine the stiffness of the element in the operation stage, taking into account the damage, behavior of concrete in tension over a macrocrack, the stress concentration at crack tip, the fracture process zone in it.In the model adopted by two separate cross-section calculation schemes of element: - Before a macrocrack starting the tensile zone of normal section of the element is represented by a bundle fibers model related to H. Daniels. They have different tensile Ri, due to the development of the initial shrinkage mesocracks in concrete which have different lengths and are described by a normal distribution law. Additionally, the Kachanov-Rabotnov damage ratio parameter is introduced into design equations; - After a macrocrack starting is considered the equilibrium of reinforced concrete section with an introduction to a Irwin-Orowan mathematical sharp notch, simulating the macrocrack. Also take into account the microcracking at the top of the notch, using the S.P. Sha fictitious crack model. The analysis of stiffness calculation results of elements with the various the percentage of reinforcement by the proposed methodology and diagramming method with using various diagrams of concrete deformation was carried out. Found that the greatest influence on the stiffness by concrete behavior in tension above the macrocrack has a load exceeding the cracking moment no more than 30 %, which is especially pronounced in heavily reinforced elements. |
| Keywords. | Bending element, reinforced concrete, stiffness, stress-strain diagram, diagram method, calculation method, fracture mechanics of concrete, cracks, damage. |
| For citations: | Radaikin O.V. To improve the method of calculating the bending stiffness of reinforced concrete elements without prestressing // Izvestiya KGASU. 2012. №1(19) P.59-66. |
