Buckling of Reinforcing Steel Reinforcing Bars in Medium-Rise Reinforced Concrete Shear Walls

2018 ◽  
Vol 116 (1) ◽  
Author(s):  
Konstantinos I Christidis
Keyword(s):  
Reinforced Concrete ◽  
Shear Walls ◽  
Reinforcing Steel ◽  
Reinforcing Bars

Effects of strain-ageing on New Zealand reinforcing steel bars

2009 ◽  
Vol 42 (3) ◽  
pp. 179-186 ◽  
Author(s):  
A. Momtahan ◽  
R.P. Dhakal ◽  
A. Rieder
Keyword(s):  
Reinforced Concrete ◽  
New Zealand ◽  
Yield Strength ◽  
Seismic Design ◽  
Reinforcing Steel ◽  
Reinforcing Bars ◽  
Capacity Design ◽  
Plastic Hinges ◽  
Strain Ageing ◽  
Steel Bars

Modern seismic design codes, which are based on capacity design concepts, allow formation of plastic hinges in specified locations of a structure. This requires reliable estimation of strength of different components so that the desired hierarchy of strength of the structural components can be ensured to guarantee the formation of plastic hinges in the ductile elements. As strength of longitudinal reinforcing bars governs the strength of reinforced concrete members, strain-ageing, which has significant effect on the strength of reinforcing bars, should be given due consideration in capacity design. Strain-ageing can increase the yield strength of reinforcing steel bars and hence the strength of previously formed plastic hinges, thereby likely to force an unfavourable mechanism (such as strong beam-weak column leading to column hinging) to take place in subsequent earthquakes. In this paper, the strain-ageing effect of commonly used New Zealand reinforcing steel bars is experimentally investigated. Common New Zealand steel reinforcing bars are tested for different levels of pre-strain and different time intervals up to 50 days, and the results are discussed focussing on the extent of strain-ageing and its possible implications on seismic design provisions. The results indicate that designers need to use a higher flexural strength (in addition to overstrength) for the weaker member in checking the strength hierarchy in capacity design of reinforced concrete frames. Similarly, in designing retrofit measures to restore a damaged reinforced concrete member engineers need to take into account an increase of yield strength of the reinforcing steel bars employed in the member due to the strain-ageing phenomenon and the extent of increase in the yield strength depends on the level of damage.

Experimental Study on Flexural Behavior of Reinforced Concrete Beams with Variety Lap Splices of Reinforcing Steel Bars

2016 ◽  
Vol 845 ◽  
pp. 132-139
Author(s):  
Mochamad Teguh ◽  
Novia Mahlisani
Keyword(s):  
Experimental Study ◽  
Reinforced Concrete ◽  
Concrete Beams ◽  
Reinforced Concrete Beams ◽  
Flexural Behavior ◽  
Reinforced Concrete Structures ◽  
Reinforcing Steel ◽  
Reinforcing Bars ◽  
Lap Splices ◽  
Steel Bars

The limited lengths of reinforcing bars have been commonly found in the practical construction of most reinforced concrete structures. The required length of a bar may be longer than the available stock of steel length. For maintaining desired continuity of the reinforcement in almost all reinforced concrete structures, some reinforcing bars should be carefully spliced. In the case of long flexural beam, bar installers end up with two or even more pieces of steel that must be spliced together to accomplish the desired steel length. An experimental study was conducted to investigate flexural behavior of reinforced concrete beams utilizing a variety lap splices of reinforcing steel bars under two-point loading. Five variations of lap splices of reinforcing steel bars positioned at midspan of tensile reinforcement of the beam were investigated. Welded joints and overlapped splices were used to construct the variation of lap splices of reinforcing steel bars. The general trend in crack pattern, the load deflection characteristics and the mode of failure of flexural beams under two-point loading were also observed. The flexural strength comprising load-displacement response, flexural crack propagation, displacement ductility is briefly discussed in this paper.

scholarly journals Bond Strengths of Geopolymer and Cement Concretes

2010 ◽  
Vol 69 ◽  
pp. 143-151 ◽  
Author(s):  
Prabir Sarker
Keyword(s):  
Reinforced Concrete ◽  
Bond Strength ◽  
Concrete Cover ◽  
Reinforced Concrete Structures ◽  
Geopolymer Concrete ◽  
Reinforcing Steel ◽  
Test Results ◽  
Reinforcing Bars ◽  
Pull Out ◽  
Bar Diameter

Geopolymer is an inorganic alumino-silicate product that shows good bonding properties. Geopolymer binders are used together with aggregates to produce geopolymer concrete which is an ideal building material for infrastructures. A by-product material such as fly ash is mixed together with an alkali to produce geopolymer. Current research on geopolymer concrete has shown potential of the material for construction of reinforced concrete structures. Structural performance of reinforced concrete depends on the bond between concrete and the reinforcing steel. Design provisions of reinforced concrete as a composite material are based on the bond strength between concrete and steel. Since geopolymer binder is chemically different from Ordinary Portland Cement (OPC) binder, it is necessary to understand the bond strength between geopolymer concrete and steel reinforcement for its application to reinforced concrete structures. Pull out test is commonly used to evaluate the bond strength between concrete and reinforcing steel. This paper describes the results of the pull out tests carried out to investigate the bond strength between fly ash based geopolymer concrete and steel reinforcing bars. Beam end specimens in accordance with the ASTM Standard A944 were used for the tests. In the experimental program, 24 geopolymer concrete and 24 OPC concrete specimens were tested for pull out. The concrete compressive strength varied from 25 to 55 MPa. The other test parameters were concrete cover and bar diameter. The reinforcing steel was 500 MPa steel deformed bars of 20 mm and 24 mm diameter. The concrete cover to bar diameter ratio varied from 1.71 to 3.62. It was found from the test results that the failure occurred by splitting of concrete in the region bonded with the steel bar, in both geopolymer and OPC concrete specimens. Comparison of the test results shows that geopolymer concrete has higher bond strength than OPC concrete. This suggests that the existing design equations for bond strength of OPC concrete with steel reinforcing bars can be conservatively used for calculation of bond strength of geopolymer concrete.

Estimation of Corrosion Damage in Steel Reinforced Mortar Using Guided Waves

2005 ◽  
Vol 127 (3) ◽  
pp. 255-261 ◽  
Author(s):  
Henrique Reis ◽  
Benjamin L. Ervin ◽  
Daniel A. Kuchma ◽  
Jennifer T. Bernhard
Keyword(s):  
Reinforced Concrete ◽  
Guided Waves ◽  
Structural Integrity ◽  
Corrosion Damage ◽  
Propagation Mode ◽  
Reinforcing Steel ◽  
Reinforcing Bars ◽  
Accelerated Corrosion ◽  
Testing Method ◽  
Accelerated Corrosion Tests

Corrosion of reinforced concrete is a chronic infrastructure problem, particularly in areas with deicing salt and marine exposure. To maintain structural integrity, a testing method is needed to identify areas of corroding reinforcement. For purposes of rehabilitation, the method must also be able to evaluate the degree, rate, and location of damage. Toward the development of a wireless embedded sensor system to monitor and assess corrosion damage in reinforced concrete, reinforced mortar specimens were manufactured with seeded defects to simulate corrosion damage. Taking advantage of waveguide effects of the reinforcing bars, these specimens were then tested using an ultrasonic approach. Using the same ultrasonic approach, specimens without seeded defects were also monitored during accelerated corrosion tests. Both the ultrasonic sending and the receiving transducers were mounted on the steel rebar. Advantage was taken of the lower frequency (<250kHz) fundamental flexural propagation mode because of its relatively large displacements at the interface between the reinforcing steel and the surrounding mortar. Waveform energy (indicative of attenuation) is presented and discussed in terms of corrosion damage. Current results indicate that the loss of bond strength between the reinforcing steel and the surrounding concrete can be detected and evaluated.

Analytical study of tessellated structural-architectural reinforced concrete shear walls

2021 ◽  
Vol 244 ◽  
pp. 112768
Author(s):  
Mohammad Syed ◽  
Mohammad Moeini ◽  
Pinar Okumus ◽  
Negar Elhami-Khorasani ◽  
Brandon E. Ross ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Analytical Study ◽  
Shear Walls

Experimental Study of Shear-Critical Reinforced-Concrete Shear Walls under Tension-Bending Shear-Combined Cyclic Load

2020 ◽  
Vol 146 (5) ◽  
pp. 04020047
Author(s):  
Xin Nie ◽  
Jia-Ji Wang ◽  
Mu-Xuan Tao ◽  
Jian-Sheng Fan ◽  
Y. L. Mo ◽  
...  
Keyword(s):  
Experimental Study ◽  
Reinforced Concrete ◽  
Cyclic Load ◽  
Shear Walls

Passive corrosion control and active corrosion prevention of the reinforced concrete structures by electrochemical chloride removal and inhibitors

2013 ◽  
Vol 61 (1) ◽  
pp. 32-37 ◽  
Author(s):  
Guofu Qiao ◽  
Yi Hong ◽  
Tiejun Liu ◽  
Jinping Ou
Keyword(s):  
Reinforced Concrete ◽  
Concrete Structures ◽  
Concrete Cover ◽  
Reinforced Concrete Structures ◽  
Reinforcing Steel ◽  
Corrosion Control ◽  
Cell Potential ◽  
Content Type ◽  
Chloride Removal ◽  
Active Corrosion

Purpose – The aim of this paper was to investigate the passive corrosion control and active corrosion protective effect of the reinforced concrete structures by electrochemical chloride removal (ECR) method and inhibitors approach, respectively. Design/methodology/approach – The concentration of aggressive chloride ion distributed from the reinforcing steel to the surface of the concrete cover was analyzed during the ECR processes. Besides, the half-cell potential, the concrete resistance R c , the polarization resistance R p and the capacitance of double layer C dl of the steel/concrete system were used to characterize the electrochemical performance of the concrete prisms. Findings – The effectiveness of ECR could be enhanced by increasing the amplitude of potential or prolonging the time. Inhibitor SBT-ZX(I) could successfully prevent the corrosion development of the reinforcing steel in concrete. Originality/value – The research provides the scientific basis for the practical application of ECR and inhibitors in the field.

Seismic behaviors of squat reinforced concrete shear walls under freeze-thaw cycles: A pilot experimental study

2016 ◽  
Vol 124 ◽  
pp. 49-63 ◽  
Author(s):  
Wei Yang ◽  
Shan-Suo Zheng ◽  
De-Yi Zhang ◽  
Long-Fei Sun ◽  
Chuan-Lei Gan
Keyword(s):  
Experimental Study ◽  
Reinforced Concrete ◽  
Shear Walls ◽  
Freeze Thaw ◽  
Seismic Behaviors
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