Reliability evaluation of reinforced concrete columns designed by Eurocode for wind-dominated combination considering random loads eccentricity

2019 ◽  
Vol 23 (1) ◽  
pp. 146-159 ◽  
Author(s):  
Youbao Jiang ◽  
Suixiang Peng ◽  
Michael Beer ◽  
Lei Wang ◽  
Jianren Zhang
Keyword(s):  
Reinforced Concrete ◽  
Failure Probability ◽  
Limit State ◽  
Concrete Columns ◽  
State Function ◽  
Reinforced Concrete Columns ◽  
Compression Failure ◽  
Random Loads ◽  
Standard Design ◽  
Total Failure

With the capacity models in the 2004 edition of the European Committee for Standardization’s Standard Design of Concrete Structures, a more realistic limit state function is obtained for reinforced concrete columns with random loads eccentricity. Using this function, the applicability of the code-based design factors is discussed. Taking the wind-dominated combination as an example, the probabilistic distribution of loads eccentricity and the statistics of column resistance are analyzed for representative cases. The analysis indicates that the possible loads eccentricity is scattered over a large range, and the probabilistic model of column resistance varies from case to case, which is largely different from the resistance model assumed in previous reliability calibration. With Monte Carlo simulation, the column reliability and the contributions of both tension failure and compression failure to the total failure probability are calculated and obtained for different cases. The results show that the fixed loads eccentricity criterion underestimates differences in the reliability of columns for different loads eccentricity cases and overestimates the column reliability in some tension failure cases. Furthermore, it is found that the tension failure mode contributes most to the total failure probability for not only some columns designed to fail in tension failure but also for some columns designed to fail in compression failure. To attain a robust design, a group of optimum wind load factors varying with cases is recommended. The new calibration results prove that the recommended wind local factors can achieve a better goal.

Combined Reinforced Concrete Columns Strengthening with Steel Clipping and Concrete Surfacing

2021 ◽  
pp. 11-22
Author(s):  
Ю. Г. Москалькова ◽  
С. В. Данилов ◽  
В. А. Ржевуцкая
Keyword(s):  
Reinforced Concrete ◽  
Load Transfer ◽  
Limit State ◽  
Concrete Columns ◽  
Ultimate Limit State ◽  
Concrete Core ◽  
Reinforced Concrete Columns ◽  
Entire Height ◽  
Complex Structural ◽  
Ultimate Limit

Постановка задачи. Исследуется метод усиления железобетонных колонн устройством стальной обоймы с обетонированием, который позволяет восстанавливать эксплуатационные показатели колонн, имеющих значительные дефекты и повреждения. Предпосылкой настоящих исследований явилось предположение о том, что усиление стальной обоймой с обетонированием является эффективным способом повышения несущей способности железобетонных колонн, причем вариант приложения нагрузки - только на бетонное ядро или ко всему сечению - существенно на эффективность усиления не влияет. В связи с этим целью исследования является определение необходимости устройства стального оголовка и включения в работу ветвей стальной обоймы при условии обетонирования стержня колонны по всей высоте. Результаты и выводы. Рациональным признан способ передачи нагрузки только на бетонное ядро усиленных колонн, поскольку устройство оголовка стальной обоймы требует применения сложных конструктивно-технологических решений, но при этом дополнительно увеличивает несущую способность незначительно (согласно проведенным исследованиям менее чем на 10 %). Ввиду отсутствия необходимости устройства конструкций стального оголовка снижаются трудоемкость и сроки производства работ по усилению колонн. Statement of the problem. The method of strengthening reinforced concrete columns with a steel clipping and the concrete surfacing is investigated. This method allows one to repair the columns with significant defects and damage. The prerequisite for this study was the assumption of strengthening with a steel clipping and the concrete surfacing is an effective way to increase the ultimate limit state of reinforced concrete columns, furthermore, the option of applying the load (only to the concrete core or to the entire section) does not significantly affect the strengthening effectiveness. In this regard, the purpose of the investigation was to identify the need to include the steel jacketing in the work, on the condition the column is coated with concrete along with the entire height. Results and conclusions. The load transfer method only to the concrete core of the strengthened columns is recognized as rational since the device of the steel clipping head requires the use of complex structural and technological solutions, but at the same time additionally increases the ultimate limit state insignificantly (according to the studies by less than 10 %). Due to the absence of the need to establish structures of the steel jacketing head, the labor intensiveness and terms of work production on strengthening the columns are reduced.

New light on performance of short and slender reinforced concrete columns under random loads

2001 ◽  
Vol 23 (2) ◽  
pp. 147-157 ◽  
Author(s):  
David M. Milner, Jr ◽  
Enrico Spacone ◽  
Dan M. Frangopol
Keyword(s):  
Reinforced Concrete ◽  
Concrete Columns ◽  
Reinforced Concrete Columns ◽  
Random Loads

Failure Analysis of Reinforced Concrete Columns after High Temperature

2012 ◽  
Vol 157-158 ◽  
pp. 1578-1581 ◽  
Author(s):  
Li Li Bai ◽  
Tao Song
Keyword(s):  
Reinforced Concrete ◽  
High Temperature ◽  
Failure Analysis ◽  
Failure Modes ◽  
Limit State ◽  
Concrete Columns ◽  
State Equation ◽  
Single Factor ◽  
Reinforced Concrete Columns ◽  
Eccentric Compression

Mechanics models of RC(reinforced concrete) columns is established, after the limit state equation was formed, the failure modes of RC eccentric compression columns after high temperature is analyzed under considering various failure paths. Analysis results indicates that failure analysis is not safe under considering single failure mode, so comprehensive considering failure modes is more matching the true situation than only considering single factor when evaluate reliability of RC eccentric compression columns post-fire

scholarly journals Combined axial and flexural loads in short reinforced concrete columns in fire: ultimate limit state curves using 500 °C isotherm method

2018 ◽  
Vol 11 (1) ◽  
pp. 163-182
Author(s):  
J. S. SUAZNABAR ◽  
V. P. SILVA
Keyword(s):  
Reinforced Concrete ◽  
Cross Sections ◽  
Limit State ◽  
Concrete Columns ◽  
Ultimate Limit State ◽  
Reinforced Concrete Columns ◽  
The Cross ◽  
In Fire ◽  
Ultimate Limit

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.

scholarly journals EVALUATION METHOD OF LIMIT STATE OF COLLAPSE FOR REINFORCED CONCRETE COLUMNS

2008 ◽  
Vol 64 (2) ◽  
pp. 298-313
Author(s):  
Toshiya TADOKORO ◽  
Koichi TANAKA ◽  
Yukihiro TANIMURA ◽  
Hiroshi KUROKAWA ◽  
Hisamichi HATTORI ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Evaluation Method ◽  
Limit State ◽  
Concrete Columns ◽  
Reinforced Concrete Columns

SETTING A DIAGRAM APPROACH TO CALCULATING VIBRATED, CENTRIFUGED AND VIBROCENTRIFUGED REINFORCED CONCRETE COLUMNS WITH A VARIATROPIC STRUCTURE

2020 ◽  
pp. 22-34
Author(s):  
Л. Р. Маилян ◽  
С. А. Стельмах ◽  
Е. М. Щербань ◽  
М. П. Нажуев
Keyword(s):  
Experimental Data ◽  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Cross Section ◽  
Concrete Columns ◽  
Reinforced Concrete Columns ◽  
The Cross ◽  
Concrete Elements ◽  
Diagram Approach

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.

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