scholarly journals Evaluation of the Influence of the Level of Corrosion of the Reinforcing Steel in the Moment-Curvature Diagrams of Rectangular Concrete Columns

2021 ◽  
Vol 6 (3) ◽  
pp. 74-80
Author(s):  
Laura Landa-Ruiz ◽  
René Croche ◽  
Griselda Santiago-Hurtado ◽  
Victor Moreno-Landeros ◽  
Josefina Cuevas ◽  
...  

In the present work, it is proposed to include in the theoretical curves of moment-curvature (m- φ) the effect of corrosion by obtaining the decrease in the area of longitudinal reinforcing steel. The corrosion depth will be obtained from the crack width and corrosion length observed in the cover concrete. With the depth of corrosion, the area of steel that is lost will be obtained and this modification will be incorporated into the theoretical procedure to elaborate the m- φ curves. The forces of the steel will be obtained from an elastoplastic model with curved hardening and the forces of the concrete with a model that considers the effect of confinement.

2019 ◽  
Vol 289 ◽  
pp. 08005
Author(s):  
Martin Schneider ◽  
Georg Gardener

Corrosion of reinforcing steel has a great influence in reducing the lifetime of concrete structures; Carbonation of the concrete pore solution causes surface corrosion on the steel and diffusion of chloride ions through the capillary system of the concrete cover causes pitting corrosion on the steel surface. Corrosion of metals is highly dependent on the environmental conditions. Exposure to chloride ions can be critical to the service life of reinforced concrete structures. The durability of reinforced concrete structures exposed to deicing salt or marine environments can be affected by impact of chloride ions. Detection methods for the rate of corrosion of non-destructive and destructive procedures were analysed. The potential mapping applied on the concrete surface was discussed as a standard method for corrosion detection and will be explained in detail including the application boundaries of the method. It is assumed that the corrosion behaviour of reinforcing steel depends on crack widths. To analyse that, 8 coated and 8 uncoated test samples with different concrete strength classes were used. The concrete objects were exposed to a 3% sodium chloride solution. The corrosion behaviour of reinforcing steel is analysed by using potential mapping with different reference electrodes (Ag/AgCl and Cu/CuSO4). The results show a significant correlation between crack size and protection system on the surface. The maximum crack width with a low indication of corrosion was found to be 0.1 mm.


Author(s):  
T. Y. Lee ◽  
K. J. Chung

This study is aimed to develop the model of fiber element in the Vector Form Intrinsic Finite Element (VFIFE) to analyze the plastic hinges of reinforced-concrete columns for bridges subjected to extreme earthquakes. The VFIFE, a new computational method, is adopted in this study because of the superior in managing the engineering problems with material nonlinearity, discontinuity, large deformation and arbitrary rigid body motions of deformable bodies. In the past study, a plastic hinge is idealized as a bilinear elastoplastic model with a fracture moment. In order to analyze the realistic behavior of the plastic hinge, especially in ultimate state, the fiber element is developed to simulate the plastic hinge by using stress-strain relations in cover concrete, core concrete and steel fibers. The developed fiber element is verified to be feasible and accurate through numerical simulation. A three-span-continuous isolated bridge is analyzed to investigate the function of the columns and unseating prevention devices and to predict the collapse situation of the whole bridge. In addition, the analysis results are compared between the fiber element and bilinear elastoplastic element.


2019 ◽  
Vol 5 (7) ◽  
pp. 1440-1451
Author(s):  
Ernesto Fenollosa ◽  
Iván Cabrera ◽  
Verónica Llopis ◽  
Adolfo Alonso

This article shows the influence of axial force eccentricity on high strength concrete columns design. The behavior of columns made of normal, middle and high strength concrete with slenderness values between 20 and 60 under an eccentric axial force has been studied. Structural analysis has been developed by means of software which considers both geometrical and mechanical non-linearity. The sequence of points defined by increasing values of axial force and bending moment produced by eccentricity has been represented on the cross-section interaction diagram until failure for each tested column. Then, diagrams depicting the relationship between failure axial force and column's slenderness have been drawn. The loss of bearing capacity of the member for normal and middle strength columns when compared with the bearing capacity of their cross-section is more noticeable as axial force eccentricity assumes higher values. However, this situation reverses for high strength columns with high slenderness values. On the basis of results obtained, the accuracy level for the moment magnifier method was checked. Despite the good concordance in most of the cases, it was verified that the moment magnifier method leads to excessively tight results for high strength concrete columns with high slenderness values. In these specific cases, a coefficient which amends the column rigidity is proposed so as to obtain safer values.


2003 ◽  
Vol 45 (1) ◽  
pp. 7-32 ◽  
Author(s):  
A.A. Sagüés ◽  
M.A. Pech-Canul ◽  
A.K.M. Shahid Al-Mansur

2018 ◽  
Vol 931 ◽  
pp. 321-327
Author(s):  
Viktor A. Muradyan

The article deals with the main advantages of reinforced concrete columns with recessed fittings. The method of testing the prototype columns is described. In addition, the influence of various factors on the fracture pattern and bearing capacity of such columns is explained. The standard reinforced concrete columns are given below and the optimal parameters for saving reinforcing steel are observed [1-7].


2013 ◽  
Vol 405-408 ◽  
pp. 657-663
Author(s):  
Yu Mei Teng ◽  
Ye Tian ◽  
James Liu

This paper presents experimental results of a series of large-scale reinforced concrete circular and square columns tested under lateral cyclic displacement excursions while simultaneously subjected to constant axial load. All the specimens contained only minimal transverse steel and were then retrofitted with CFRP or GFRP jackets except control specimens. The measured hysteretic loops of the moment vs. curvature and shear vs. deflection relationships are reported for each specimen. It was observed that both CFRP and GFRP wrapping could provide effective confinement and significantly improve the seismic performance of columns. The effectiveness of FRP in enhancing column ductility relates more closely to its tensile strength than stiffness, thus the application of GFRP confinement to concrete columns is promoted due to obtainability and economical concern.


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