Experimental Investigations of Loading Rate Effects in Reinforced Concrete Columns

2012 ◽  
Vol 138 (8) ◽  
pp. 1032-1041 ◽  
Author(s):  
W. Ghannoum ◽  
V. Saouma ◽  
G. Haussmann ◽  
K. Polkinghorne ◽  
M. Eck ◽  
...  
2000 ◽  
Vol 27 (5) ◽  
pp. 1011-1020 ◽  
Author(s):  
Michèle Thériault ◽  
Kenneth W Neale

Step-by-step design procedures are proposed for the axial load capacity enhancement of circular and rectangular reinforced concrete columns confined with fibre reinforced polymer (FRP) wraps. The design methods are intended for practicing engineers in that they are relatively simple to apply and are made readily available in a design code format. Commentaries are presented to explain the design philosophy and rationale leading to the various design equations. For purposes of validation, numerical results based on the proposed design equations are compared against available experimental data. Strengthening limits, as governed by creep and fatigue phenomena, are also proposed. Whenever test data are found to be too limited, conservative approaches are adopted. Various experimental investigations are suggested for future work to further validate and update the design equations.Key words: FRP strengthening, concrete columns, axial loading, confinement, design.


2019 ◽  
Vol 23 (4) ◽  
pp. 779-793
Author(s):  
SY Xiao ◽  
JB Li ◽  
YL Mo

The dynamic behaviour of reinforced concrete columns is inevitably affected by loading rate. This article reports the effect of loading rate on the dynamic behaviour of reinforced concrete columns under cyclic loading. Dynamic tests on reinforced concrete columns at five different loading rates were carried out using the MTS electro-hydraulic servo system. The cyclic loading was controlled by displacement with a loading rate ranging from 0.1 to 10 mm/s. Based on the test results, the effects of the loading rate on the hysteresis curves and the envelope curves of reinforced concrete columns were investigated. The research focused on the effect of loading rate on strength and deformation behaviour, including yielding and ultimate strengths as well as displacement. Finally, the effects of loading rate on the dissipated energy capabilities, the pinching effects and the stiffness degradation of reinforced concrete columns were also critically examined.


2011 ◽  
Vol 05 (02) ◽  
pp. 151-165 ◽  
Author(s):  
ZHISHEN WU ◽  
ADEKUNLE PHILIPS ADEWUYI ◽  
SONGTAO XUE

Prompt and accurate detection of realistic damage in constructed facilities is critical for effective condition assessment and structural health monitoring. This paper reports the experimental investigations of eccentric reinforced concrete columns mounted onto a shaking table and subject to progressively increasing seismic excitations. The investigation was aimed at studying the changes in the dynamic parameters in order to assess the structural conditions of the concrete columns after each post-seismic stage. The dynamic response of the structure was measured using accelerometers, traditional foil-strain gauges, and long-gauge fiber Bragg grating (FBG) sensors. The post-seismic conditions of the columns were evaluated via vibration-based damage identification methods. Results from this study demonstrate the applicability of specially packaged surface-mounted long-gauge FBG sensors for detecting the initiation and the progression of cracks due to reverse dynamic loads. The concept of modal macrostrain analysis was also introduced to identify and localize mild damage due to the applied seismic excitations of increasing intensities. The performance of the sensors for structural identification is also discussed.


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.


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