Evaluation of the Carrying Capacity of Rectangular Steel-Concrete Columns

Experimental studies of rectangular steel-concrete columns under centric compression with random eccentricity were conducted. The stress-strain state and the carrying capacity exhaustion have been assessed. The regression dependence is proposed to determine the maximum carrying capacity of such columns. The mathematical model takes into account the combined influence of the physical and geometric characteristics of the columns, such as their length, crosssectional area, casing thickness, prism strength of concrete, yield strength of steel, modulus of elasticity of both steel and concrete. The correspondence of the obtained model to the experimental data, as well as the significance of the regression parameters are confirmed by the Fisher and Student criteria

ПРОГНОЗУВАННЯ ОБСЯГІВ ПАСАЖИРСЬКИХ ПЕРЕВЕЗЕНЬ В ДАЛЬНЬОМУ ЗАЛІЗНИЧНОМУ СПОЛУЧЕННІ НА ОСНОВІ БАГАТОФАКТОРНОГО АНАЛІЗУ

Passenger railway transport has a leading position in the Ukrainian passenger transportation services market. According to the current legislation, railway transport is a natural monopoly, since most long-distance passenger transportation is performed by rail. The issue of improving the methods of predicting the long-distance passenger traffic load has been relevant because reliable predictions are the basis for determining the need for material, technical, labor and financial resources in planning the operation and further development of the domestic railway passenger complex.The size of passenger transportation by railway transport is influenced by a variety of factors, the most significant of which are economic and social factors, namely: population, income and tariffs for long-distance rail transport. These factors are the basis of the model of study of the volume of passenger traffic by long-distance rail transport. In order to determine the predictive estimate of passenger traffic volumes on the basis of the given economic -mathematical model it is necessary to make a predictive estimate of the magnitude of the above mentioned factors.The article substantiates the possibility of a complex use of economical mathematical simulation and formalized prediction methods to obtain reliable prediction estimates of passenger load in long-distance railway transportation in the short- and medium-term periods of advance. The determined methodical approaches and proposed practical recommendations give an opportunity to obtain a predictive estimation of the long-distance passenger load using a combination of correlation and regression analysis of socio-economic factors and their predictive extrapolation. This allows improving the quality of planning at the Ukrainian passenger railway complex. A qualitative short-term predictive estimate of long-distance passenger traffic load which takes into account the existing social and economic conditions was obtained.Питання удосконалення методів прогнозування обсягів пасажирських перевезень в дальньому сполученні залишається актуальним, оскільки достовірні прогнозні оцінки є підґрунтям для визначення потреби в необхідних ресурсах при плануванні роботи залізничного пасажирського комплексу. В статті обґрунтовані методичні підходи та запропоновані практичні рекомендації, які дають можливість отримати прогнозну оцінку обсягів перевезень пасажирів в дальньому сполученні на основі суміщення методів кореляційно – регресійного аналізу соціально – економічних факторів та їх прогнозної екстраполяції

Using statistical methods to determine the load-bearing capacity of rectangular CFST columns

In the current practice of construction and design of transport facilities, structures with external reinforcement are commonly used which effectively resist compression. The use of steel-concrete and composite structures enables us to reduce material consumption and cost of structures significantly. There are a few established approaches used to evaluate the load-bearing capacity of steel-concrete structures under axial and eccentric compression, each being based on the initial prerequisites, which underlie the calculation formulas. In this paper, the functional relationship of the value of the maximum load-bearing capacity of rectangular concrete-filled steel tubular (CFST) columns under axial compression with the random eccentricity is plotted. A regression model is proposed based on the methods of mathematical statistics, which allows for the evaluation of the impact of geometrical and physical characteristics of rectangular CFST columns on the value of their load-bearing capacity. The correspondence of the obtained model to the experimental data, as well as the significance of the regression parameters are confirmed by Fisher and Student criteria

Using statistical methods to determine the load-bearing capacity of rectangular CFST columns

In the current practice of construction and design of transport facilities, structures with external reinforcement are commonly used which effectively resist compression. The use of steel-concrete and composite structures enables us to reduce material consumption and cost of structures significantly. There are a few established approaches used to evaluate the load-bearing capacity of steel-concrete structures under axial and eccentric compression, each being based on the initial prerequisites, which underlie the calculation formulas. In this paper, the functional relationship of the value of the maximum load-bearing capacity of rectangular concrete-filled steel tubular (CFST) columns under axial compression with the random eccentricity is plotted. A regression model is proposed based on the methods of mathematical statistics, which allows for the evaluation of the impact of geometrical and physical characteristics of rectangular CFST columns on the value of their load-bearing capacity. The correspondence of the obtained model to the experimental data, as well as the significance of the regression parameters are confirmed by Fisher and Student criteria

Regression equations for circular CFST columns carrying capacity evaluation

Within the last decades, a considerable amount of experimental studies have been carried out by numerous researchers across the world with the purpose to study the carrying capacity of concrete-filled steel tubular (CFST) columns and evaluation of their stressed-strained state. The array of the obtained results have allowed designing a mathematical model to determine the maximum carrying capacity value of such constructions using the methods of mathematical statistics. The authors obtained three types of regression equations for short and long circular CFST columns with different geometrical and physical properties under axial compression. Statistical quality of the obtained models was verified by both regression equation quality in general and statistical significance of the equation parameters. The comparison of the obtained carrying capacity values with the results calculated by Eurocode 4 and AIJ methodologies allows making a conclusion on the sufficient calculation accuracy of the designed mathematical models

Regression equations for circular CFST columns carrying capacity evaluation

Within the last decades, a considerable amount of experimental studies have been carried out by numerous researchers across the world with the purpose to study the carrying capacity of concrete-filled steel tubular (CFST) columns and evaluation of their stressed-strained state. The array of the obtained results have allowed designing a mathematical model to determine the maximum carrying capacity value of such constructions using the methods of mathematical statistics. The authors obtained three types of regression equations for short and long circular CFST columns with different geometrical and physical properties under axial compression. Statistical quality of the obtained models was verified by both regression equation quality in general and statistical significance of the equation parameters. The comparison of the obtained carrying capacity values with the results calculated by Eurocode 4 and AIJ methodologies allows making a conclusion on the sufficient calculation accuracy of the designed mathematical models

A statistical method for predicting the eccentric load capacity of rectangular concrete filled steel tubular columns

The article deals with the integrated approach to the study of the behaviour of rectangular CFST columns under eccentric compression. Such an approach includes the development of methods for assessing the magnitude of the carrying capacity, assessing the degree of reliability and credibility of the obtained results, as well as studying the nature of the development of columns deformations at various stages of loading. The authors developed a mathematical model for calculation of columns carrying capacity under eccentric compression based on statistical methods. Substantial amount of experimental data collected by the world leading laboratories enabled obtaining a regression dependence of the columns carrying capacity that takes into account the impact of the physical and geometric characteristics of such structures. High degree of model confidence is confirmed by a comparative analysis with experimental results that are not involved in the development of the model, as well as with calculations performed according to Eurocode, Japanese and Chinese regulatory documents. The article presents experimental studies of the nature of deformations development on the surface of the steel shell and inside the concrete core of various lengths rectangular columns. As a result of the experimental tests, it was established that the longitudinal strains of the compressed area of the shell have the most significant impact on the bearing capacity of eccentrically compressed steel concrete samples

A statistical method for predicting the eccentric load capacity of rectangular concrete filled steel tubular columns

The article deals with the integrated approach to the study of the behaviour of rectangular CFST columns under eccentric compression. Such an approach includes the development of methods for assessing the magnitude of the carrying capacity, assessing the degree of reliability and credibility of the obtained results, as well as studying the nature of the development of columns deformations at various stages of loading. The authors developed a mathematical model for calculation of columns carrying capacity under eccentric compression based on statistical methods. Substantial amount of experimental data collected by the world leading laboratories enabled obtaining a regression dependence of the columns carrying capacity that takes into account the impact of the physical and geometric characteristics of such structures. High degree of model confidence is confirmed by a comparative analysis with experimental results that are not involved in the development of the model, as well as with calculations performed according to Eurocode, Japanese and Chinese regulatory documents. The article presents experimental studies of the nature of deformations development on the surface of the steel shell and inside the concrete core of various lengths rectangular columns. As a result of the experimental tests, it was established that the longitudinal strains of the compressed area of the shell have the most significant impact on the bearing capacity of eccentrically compressed steel concrete samples