A fibre model to simulate the cross-sectional behaviour of reinforced concrete columns under multi-directional earthquake loading

2000 ◽  
Vol 77 (4) ◽  
pp. 403-411 ◽  
Author(s):  
Stefan Parche
Author(s):  
Л. Р. Маилян ◽  
С. А. Стельмах ◽  
Е. М. Щербань ◽  
М. П. Нажуев

Состояние проблемы. Железобетонные элементы изготавливаются, как правило, по трем основным технологиям - вибрированием, центрифугированием и виброцентрифугированием. Однако все основные расчетные зависимости для определения их несущей способности выведены, исходя из основного постулата - постоянства и равенства характеристик бетона по сечению, что реализуется лишь в вибрированных колоннах. Результаты. В рамках диаграммного подхода предложены итерационный, приближенный и упрощенный способы расчета несущей способности железобетонных вибрированных, центрифугированных и виброцентрифугированных колонн. Выводы. Расчет по диаграммному подходу показал существенно более подходящую сходимость с опытными данными, чем расчет по методике норм, а также дал лучшие результаты при использовании дифференциальных характеристик бетона, чем при использовании интегральных и, тем более, нормативных характеристик бетона. Statement of the problem. Reinforced concrete elements are typically manufactured according to three basic technologies - vibration, centrifugation and vibrocentrifugation. However, all the basic calculated dependencies for determining their bearing capacity were derived using the main postulate, i.e., the constancy and equality of the characteristics of concrete over the cross section, which is implemented only in vibrated columns. Results. Within the framework of the diagrammatic approach, iterative, approximate and simplified methods of calculating the bearing capacity of reinforced concrete vibrated, centrifuged and vibrocentrifuged columns are proposed. Conclusions. The calculation according to the diagrammatic approach showed a significantly better convergence with the experimental data than that using the method of norms, and also performs better when using differential characteristics of concrete than when employing integral and particularly standard characteristics of concrete.


Author(s):  
Maurício Castelo Branco de Noronha Campos ◽  
Paulo Marcelo Vieira Ribeiro ◽  
Romilde Almeida de Oliveira

abstract: This study addresses a numerical analysis of reinforced concrete columns in which the lengths are significantly larger than their widths with a rectangular cross section. Numerical simulations of 1,440 cases were performed, each case simulated with the single bar model, isolated bar model and mesh model, in addition, 3D model simulations were carried out. For the validation of 3D models and bar models, comparisons were made between the numerical simulation e experimental results of 24 reinforced concrete columns. Second order effects were analyzed on the vertical moment at the edge of the columns in which the lengths are significantly larger than the widths (localized second-order effects) and also the values of the horizontal moments along the cross sectional length in the mesh model. Influences of the main variables were observed influencing the behavior of the columns in which the lengths are significantly larger than their widths: the ratio between the cross sectional dimensions, the slenderness and the stresses (normal stress and bending moment around the axis of greatest inertia).


2013 ◽  
Vol 838-841 ◽  
pp. 648-652
Author(s):  
Jian Long Cao ◽  
Hai Tao Long ◽  
Wen Luo

Using the finite element analysis software ABAQUS, the section temperature field of reinforced concrete columns under fire was analyzed. On this basis, the influence of the section size, the number of heated surface and the time of fire on the surface temperature were analyzed. Calculations indicate that the impact of the section size on temperature field cannot be considered when one surface was heated, three or surrounded by fire-sectional dimensions the influence was time-related. When the cross-sectional size reaches a certain value, the number of exposed surface on the temperature field can be neglected. Sectional temperature increased by time and the temperature rise rate is high at start then slow down close by fire surface, however, the rate is more stable all the time at internal surface.


2012 ◽  
Vol 193-194 ◽  
pp. 1086-1089 ◽  
Author(s):  
Moacir Kripka ◽  
Guilherme Fleith de Medeiros

This work presents the development and implementation of a mathematical formulation for obtaining optimal sections of reinforced concrete columns subjected to uniaxial flexural compression. In order to minimize the cost of the reinforced concrete columns, the amount and diameters of the reinforcement bars and the dimensions of the columns cross sections were considered as discrete variables. The optimization was made by Harmony Search optimization method, a metaheuristic inspired by music performance. Initially, the economical cost of each material (concrete, steel and formwork) were considered, as usual in most optimization strategies. In the sequence, the lesser environmental cost was studied, by considering the Life Cicle Assessment (LCA) to determine the global warming potential. The results obtained led to a different configuration when the objective is a reduction in carbon dioxide (CO2) emissions, regarding the optimum economical cost.


Author(s):  
Rodrigo Oliveira Cruz ◽  
Afonso Celso de Castro Lemonge

The sizing of reinforced concrete structures is influenced by high magnitude forces and, as a result of its calculations, some designs may present specifications that are not optimum. In this case, it can occur exaggerated dimensions and an oversized structure resulting in financial losses and material wastes. Thus, it can be applied to the sizing, optimization techniques to achieve the best solution regarding, as an example, efficiency and material costs. This paper presents the optimization of cross-sectional areas of reinforced concrete columns using a Genetic Algorithm (GA) and considering the structure subjected to an axially compressive force and biaxial bending. It was developed an algorithm using the formulation of Araújo (2014) for the sizing associated with Deb’s Genetic Algorithm (2001). The developed software present solutions as cross-sectional areas of a column regarding the minimization of its costs and in which its reinforcement steel positions and diameters are optimized. Its dimensions and concrete resistance may also be optimized as a choice of the designer/engineer. The algorithm was applied to an example and had its solutions compared with other authors. Its results had achieved feasible solutions and shown similar costs.


2014 ◽  
Vol 644-650 ◽  
pp. 5019-5022
Author(s):  
Xue Feng Liu ◽  
Qing Xin Ren ◽  
Lian Guang Jia

In this paper, temperature field analysis of concrete filled steel tube reinforced concrete columns in fire has been carried on. A finite element model for concrete filled steel tube reinforced concrete columns in fire is developed by ABAQUS. The cross-sectional temperature field distribution regularity of concrete filled steel tube reinforced concrete columns in fire has been obtained. Parameter analysis such as fire duration time and steel ratio on the column section temperature field is conducted, and this provide the reference for the further analysis of concrete filled steel tube reinforced concrete columns.


2018 ◽  
Vol 11 (1) ◽  
pp. 163-182
Author(s):  
J. S. SUAZNABAR ◽  
V. P. SILVA

Abstract Ultimate limit state curves of short reinforced concrete columns in fire situation are going to be presented in this paper. The authors created a code developed in Matlab. It makes a discretization of the cross sections of the columns and calculates the equilibrium integrals of them. The curves were plotted with the code considering the 500 °C isotherm method.


Author(s):  
L. R. Mailyan ◽  
S. A. Stel'makh ◽  
E. M. Shcherban ◽  
M. P. Nazhuev

Statement of the problem. Reinforced concrete elements are typically manufactured according to three basic technologies - vibration, centrifugation and vibrocentrifugation. However, all the basic calculated dependencies for determining their bearing capacity were derived using the main postulate, i.e., the constancy and equality of the characteristics of concrete over the cross section, which is implemented only in vibrated columns. Results. Within the framework of the diagrammatic approach, iterative, approximate and simplified methods of calculating the bearing capacity of reinforced concrete vibrated, centrifuged and vibrocentrifuged columns are proposed.Conclusions. The calculation according to the diagrammatic approach showed a significantly better convergence with the experimental data than that using the method of norms, and also performs better when using differential characteristics of concrete than when employing integral and particularly standard characteristics of concrete.


Sign in / Sign up

Export Citation Format

Share Document