Stress-strain Diagrams of Concrete Under Repeated Loads with Compressive Stresses

Abstract

The article discusses the general characteristics of the deformation of concrete under repeated cyclic loads of compressive stresses observed in the experiments executed by the authors, as well as domestic and foreign researchers. Based on experimental data of fixed and variable levels of stress, limits have been defined for reference points of stabilization of strains and stresses. The plotted stabilization diagram outlines the accumulated deformation with the increase of the number of cycles and shows the stress level above which the concrete fails after a finite number of cycles. The total deformation of concrete in the initial system of coordinates is determined by summing up the incremental strain of each cycle calculated in the new system of coordinates. This technique is used to determine the number of cycles until the stabilization of the deformation at low stress levels and the number of cycles until the failure of concrete at high levels of stress.

Energy Model in Calculating the Strength Characteristics of the Reinforced Concrete Components

“…In the preliminary calculations of the presented energy model, the strains in the concrete are equivalent to the force applied to produce deformation in a concrete specimen (prism, cylinder) under stress, which is equal to the area used in calculation of the normative diagram. Energy models are important for the transition to the analysis of structures in complex stress modes, since they take into account the dissipation of energy on the relief lines [5,6,7,8]. In the complete diagrams of the rebar (if…”

Unified Methodology for Strength and Stress Analysis of Structural Concrete Members

“…A review of the analytical constitutive relationships for concrete and steel reinforcement, with a detailed description of their competency, weaknesses, and powerful aspects, was given in the literature (Oukaili [30]; Popovics [31]; Naaman [32]; Karpenko et al [33]). Relationships proposed by Karpenko et al [33,34], which were originally developed considering most of the deficiencies, became widespread in the 1990s. In this study, the short-term uniaxial stress-strain diagram adopted for the concrete and steel is based on these relationships.…”

An elastoplastic damage constitutive model for hybrid steel-polypropylene fiber reinforced concrete

“…Initially, as per the fitting results from independent studies concerning the stress-strain relation of plain concrete, many practical models in the form of pure mathematical expression were proposed (Feng et al., 2020; Li et al., 1996; Moradi et al., 2020; Sima et al., 2008). On that basis, some more sophisticated empirical models were established subsequently to account for the effects of concrete strength (normal strength, high strength, and ultra-high strength), loading rate (static loading, dynamic loading, and impact loading), and loading path (uniaxial monotonic/cyclic loading, multiaxial loading) (Breccolotti et al., 2015; Karpenko et al., 2015; Xu and Wen, 2016). Under specific conditions, these models can describe the stress-strain behaviors with high accuracy, although the involved physical mechanisms are not very sufficient (Moradi et al., 2020; Yang et al., 2019).…”