| Abstrakt: |
The real nonlinear diagrams of concrete, reinforcement and steel-fiber concrete under dynamic loading are formulated and analytically described. Theoretical and experimental studies of the operation of compressed and non-centrally compressed elements with different levels of load application eccentricity under static and short-term dynamic loads are carried out. 3 reinforced concrete and 9 steel-fiber concrete elements were manufactured and tested for short-term dynamic load under central and off-center compression. New experimental data characterizing the process of deformation and destruction of steel-reinforced concrete models of columns have been obtained. Also, the schemes of destruction and cracking, the dependence of changes in the dynamic load over time, the movement of concrete, reinforcement and steel-fiber concrete over time are obtained. A method has been developed for calculating the strength and stability of such elements, taking into account the reinforcement of the section with steel fiber concrete. The influence of the use of zone reinforcement with steel fiber of compressed and non-centrally compressed reinforced concrete elements is numerically analyzed. Numerical calculations of compressed and non-centrally compressed elements by the finite element method in the "LIRA"EVC are performed. The isofields of stresses and displacements in the construction materials are obtained. The results of the calculation according to the developed methodology are compared with the results of experimental data. The optimal variant of the application of zone reinforcement made of steel fiber for compressed and non-centrally compressed elements operating under static and short-term dynamic loads is proposed. The analysis of the calculation results based on the developed method for calculating the strength of normal sections of non-centrally compressed reinforced concrete and steel-fiber concrete, based on the deformation model, and their comparison with the data of experimental studies under short-term dynamic loading show that the deviations are on average 10-18 %, which indicates that the developed method has sufficient accuracy to solve practical problems. [ABSTRACT FROM AUTHOR] |
