For instance, in the case of the fine-grain concrete columns, they provide excessively high estimates.
First, these formulas are valid only for heavy concrete. 2008 Fattah 2012) or by the statistical processing of relevant data (Mander et al. 1982 Saatcioglu and Razvi 1992 Shams and Saadeghvaziri 1997 Tsuda et al. They have significant limitations in practical application, since they were obtained either from the results of specific laboratory sample tests (Furlong 1967 Tang et al. The proposed methods for the calculation of a CFTC’s bearing capacity stipulated in regulatory instruments in a range of countries, e.g., Australia (Standard Australia AS5100.6-2004), Brazil (Brazilian Code NBR 8800:2008), Canada (CAN/CSA S16-01:2001), People’s Republic of China (China Standard GB 50010-2010), Russia (CR 266.1325800.2016), and the USA (AINSI/AISC 360:2005), as well as the general European regulations (Eurocode EN :2004), are essentially based upon empirical formulas. A comparison of the theoretical and experimental results indicates that the practical application of the developed calculation procedure gives a reliable and fairly stable estimate of the stress–strain state and the strength of concrete-filled steel tube columns.Ĭoncrete-filled steel tube columns (CFTC) are steel-reinforced concrete structures. This circumstance was not taken into account in earlier calculations. Thus, the parametric points of the concrete and steel deformation diagrams also change at each step. Second, with a step-by-step increase in the relative deformation, the lateral pressure on a concrete core and a steel shell constantly change. In particular, they can be used for self-stressing, fine-grained and other types of concrete. Since the proposed dependencies to determine the strength and the ultimate relative strain of volumetrically compressed concrete are obtained phenomenologically, they are more versatile than the commonly used empirical formulas. First, the steel shell and the concrete core work under conditions of a complex stress state. In this case, two main factors are taken into account.
A distinctive feature of the proposed approach is the method of the multipoint construction of deformation diagrams for a concrete core and steel shell. The main dependencies that allow the realization of the deformation calculation model in practice are considered. The aim of this work is to propose a technique to calculate the strength of short concrete-filled steel tube columns under the short-term action of a compressive load, based on the phenomenological approach and the theoretical positions of reinforced concrete mechanics.
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