scholarly journals EFFECT OF YIELD STRENGTH RATIO OF LONGITUDINAL REINFORCING BARS ON DEFOMABILITY OF REINFORCED CONCRETE MEMBERS

1995 ◽  
Vol 60 (476) ◽  
pp. 129-137
Author(s):  
Jun FURUKAWA ◽  
Hitoshi SHIOHARA ◽  
Koji OKA
Keyword(s):  
Reinforced Concrete ◽  
Yield Strength ◽  
Strength Ratio ◽  
Reinforcing Bars ◽  
Concrete Members

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.

scholarly journals Seismic design considerations of the properties of New Zealand manufactured steel reinforcing bars

1986 ◽  
Vol 19 (3) ◽  
pp. 213-246 ◽  
Author(s):  
T. Andriono ◽  
R. Park
Keyword(s):  
Reinforced Concrete ◽  
New Zealand ◽  
Yield Strength ◽  
Seismic Design ◽  
Statistical Study ◽  
Stress Strain ◽  
Moment Capacity ◽  
Monte Carlo Simulation Technique ◽  
Concrete Members ◽  
Flexural Reinforcement

A statistical study is carried out to investigate the probable stress-strain properties of Grade 275 and Grade 380 reinforcing steel manufactured in New Zealand for reinforced concrete construction. The investigation is based on extensive measured data obtained from Pacific Steel Ltd and from University of Canterbury research projects. The results obtained from this statistical study are used to calculate the 5% lower-tail normal probability value of the yield strength, which is considered to be more appropriate for use in the strength design of reinforced concrete members than the specified minimum yield strength. The results obtained from this statistical study are also used to re-evaluate the values of the currently recommended beam flexural overstrength factors used in seismic design in New Zealand, namely 1.25 if Grade 275 steel is used as flexural reinforcement and 1.40 if Grade 380 steel is used as flexural reinforcement. For this purpose, moment-curvature analyses incorporating an appropriate stress-strain model for the steel reinforcement and the Monte Carlo simulation technique are conducted to study the likely increase in the flexural strength above the ideal moment capacity of reinforced concrete members at high curvatures. Improved values for the flexural overstrength factors are recommended.

scholarly journals INFLUENCE OF CORROSION OF REINFORCING BARS ON BENDING PERFORMANCE OF REINFORCED CONCRETE MEMBERS

2006 ◽  
Vol 62 (3) ◽  
pp. 542-554 ◽  
Author(s):  
Michiaki OYADO ◽  
Toshiyuki KANAKUBO ◽  
Yasuhiko YAMAMOTO ◽  
Tsutomu SATO
Keyword(s):  
Reinforced Concrete ◽  
Reinforcing Bars ◽  
Bending Performance ◽  
Concrete Members

scholarly journals Application of high strength reinforcing bars in earthquake-resistant structure elements

2018 ◽  
Vol 195 ◽  
pp. 02015
Author(s):  
Kurniawan Setiadi Kamaruddin ◽  
Iswandi Imran ◽  
Maulana Derry Imansyah ◽  
Muhammad Riyansyah ◽  
Aris Ariyanto
Keyword(s):  
Reinforced Concrete ◽  
Yield Strength ◽  
Concrete Beam ◽  
High Strength ◽  
Reinforced Concrete Beam ◽  
Reinforcing Bars ◽  
Dissipation Energy ◽  
Reinforcing Bar ◽  
Column Joint ◽  
Normal Strength

Currently, design of reinforced concrete buildings is still dominated with normal strength reinforcing bars, not exceeding 420 MPa yield strength. Meanwhile, the use of higher strength reinforcing bars tend to increase due to some benefits in the construction, such as reducing the total weight of reinforcing bars and alleviating reinforcing bars congestions. In this study, reinforcing bars with yield strength of 520 MPa are utilized in the reinforced concrete beam-column joint. The objective is to study the seismic performance of reinforced concrete beam-column joints. A total of 3 interior beam-column joints, half-scaled specimens with different yield strengths and bar diameters was tested. One of the test specimens which was 16 mm diameter and had normal strength reinforcing bar. The other two specimens use high strength reinforcing bars, and have 16 mm and 19 mm diameter bars. Loading protocol of all the specimens is conformed with ACI 374.2. Dissipation energy and deformability of the joints is then compared. Normalized energy dissipation of the specimens with high strength reinforcing bars was slightly lower than that of the specimens with normal reinforcing bars. However, specimens with high strength reinforcing bars tend to have smaller deformability than that of the specimens with normal reinforcing bars.

scholarly journals Methods of analysis of a reinforced concrete section under bending with axial force in the post-yield range

2014 ◽  
Vol 13 (3) ◽  
pp. 119-126
Author(s):  
Jacek Korentz
Keyword(s):  
Reinforced Concrete ◽  
Axial Force ◽  
Concrete Cover ◽  
Reinforcing Bars ◽  
Concrete Members ◽  
Extreme Loads ◽  
Concrete Confinement ◽  
The Moment ◽  
The Relationship ◽  
Concrete Section

Predicting the behaviour of plastic hinges subjected to large inelastic deformations caused by extreme loads such as earthquakes plays an important role in assessing maximum stable deformation capacities of framed concrete structures. This paper presents the analytical procedure for analysing the behaviour of a reinforced concrete section under bending with axial force in the post-yield range. The following stages of section behaviour are defined: the uncracked, first cracked, yielding, cover crushing, cover spalling, buckling of bars and limit stages. The relationship between the moment and curvature in these stages, including the effects of concrete confinement, the spalling of the concrete cover, and the inelastic buckling of the reinforcing bars, is considered. The presented method makes it possible to estimate the ductility of reinforced concrete members with various longitudinal and transverse reinforcement.

scholarly journals Evaluation of the Flexural Performance and CO2 Emissions of the Voided Slab

2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Seungho Cho ◽  
Seunguk Na
Keyword(s):  
Carbon Dioxide ◽  
Reinforced Concrete ◽  
Yield Strength ◽  
Performance Test ◽  
Environmental Influence ◽  
Concrete Slab ◽  
Structural Performance ◽  
Reinforcing Bars ◽  
Reinforced Concrete Slab ◽  
Flexural Performance

Reinforced concrete is regarded as one of the ideal structural materials which comprises concrete with high compressive strength and reinforcing bars with high tensile strength. However, concrete has been pointed out that it consumes a large volume of energy and emits a lot of carbon dioxide during its manufacturing. In order to lower such environmental burdens of concrete structures, a number of studies and approaches have been carried out. The voided slab is also suggested as a new method to reduce the environmental burden since voided section of the slab would use less concrete compared with the normal reinforced concrete slab. However, no studies have evaluated the CO2 emissions and environmental performance of voided slabs. The purpose of this study was to evaluate the structural performance of voided slabs and empirically corroborate their environmental influence. The flexural performance test was carried out based on the variables of the depth of slab, types of the void former materials, and the hollowness ratio. In addition, comparison of the emission of CO2 was also performed by considering the hollowness ratio and types of void former materials over the normal reinforced concrete slab. The structural performance of the voided slab was similar or slightly higher than the normal reinforced concrete slab. The yield strength of specimens was increased approximately 10∼30% over the anticipated yield strength. Based on this result, it is considered that the voided slab would be sufficient to structural performance and beneficial to plane planning in buildings. In general, it is considered that the voided slab would be beneficial to both structural and environmental aspects. However, the test results in this research showed that the voided slab would emit more carbon dioxide emissions compared to the normal reinforced concrete slab. The main source of more CO2 emissions in the voided slab was the anchoring materials. In this research, wires were used to fix the void former materials to the reinforcing bars. In order for the voided slab to become a more eco-friendly and sustainable material, new anchoring methods such as use of recycled materials, new void former materials without anchoring, or other eco-friendly materials should be applied to reduce the emission of CO2.

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