scholarly journals LOOP ALGORITHMS FOR DUCTILITY ANALYSIS OF COLUMN REINFORCED STEEL WITH YIELD STRENGTH ABOVE 500 MPA

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
AHMAD FAZA AZMI
Keyword(s):  
Reinforced Concrete ◽  
Yield Strength ◽  
Numerical Study ◽  
Design Procedure ◽  
Strain Curve ◽  
High Strength ◽  
Confined Concrete ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Overstrength Factor

There are many benefits to the use of high-strength reinforcement (above 500 MPa) in reinforced concrete buildings. The advantages of using high-strength reinforcement are reduction steel volume and dimension, reduced construction time, reduction in reinforcement congestion, as well as savings in materials and worker cost. Meanwhile, the investigation of ductility of reinforced concrete element with high-strength reinforcement to resist earthquake effects under current design procedure is needed. In the current standard, ACI 318-71, The maximum specified yield strength was restricted to 60 Ksi (413 MPa) for reinforcement in special seismic system. There were also no ASTM standard specifications for reinforcement with yield strength above 500 MPa. In the design of seismicresisting structures, the analysis of curavture ductility and flexural overstrength factor is of important consideration in order to avoid brittle failure. This paper attempts to anaylze the ductility and re-evaluate the flexural overstrength factor of reinforced concrete column. The tensile tests of steel reinforcement with yield strength above 500 MPa generates stress-strain curve. An idealisations for the monotonic stress-strain curve proposed by mander wasadopted in this study. Whereas in this numerical study of confined concrete columns, the behavior of concrete cored is modeled by the stress-strain relationship of confined concrete proposed by Kappos-Konstantinidis. This stress strain model was used for the momen, curvature, ductility, and flexural overstrength factor analysis.

scholarly journals Effect Of Pre-Tensioned Level on Axial Stress-Strain Behaviour of Confined Concrete: A Review

2018 ◽  
Vol 7 (3.9) ◽  
pp. 18
Author(s):  
Chee Loong Chin ◽  
Chau Khun Ma ◽  
Jia Yang Tan ◽  
Abdullah Zawawi Awang ◽  
Wahid Omar
Keyword(s):  
Reinforced Concrete ◽  
Axial Stress ◽  
Strain Curve ◽  
Confined Concrete ◽  
Reinforced Concrete Buildings ◽  
Short Discussion ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Confining Effect ◽  
Strain Behaviour

External passive confinement has been used as strengthening scheme to rehabilitate existing reinforced concrete buildings. Passive confinement requires a certain lateral dilation of concrete prior to the activation of the confining effect. Applying pre-tensioned force to the confining material can eliminate the needs of such lateral dilation. This paper presents a review on previous studies conducted about pre-tensioned level in confined concrete. A short discussion is done based on the effect of pre-tensioned level to the three regions of stress-strain curve. It was found that pre-tensioned level affects the stress-strain behaviour of confined concrete. Pre-tensioned level that is too high decreases the strain capacity of the confined concrete. This review suggests that there exists an optimum pre-tensioned level for each confining material.  

Predictive Stress-Strain Models for High Strength Concrete Subjected to Uniaxial Compression

2014 ◽  
Vol 567 ◽  
pp. 476-481
Author(s):  
Nasir Shafiq ◽  
Tehmina Ayub ◽  
Muhd Fadhil Nuruddin
Keyword(s):  
Predictive Models ◽  
High Strength Concrete ◽  
Cement Content ◽  
Strain Curve ◽  
High Strength ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Strength Concrete ◽  
Strain Behavior ◽  
Four Cylinders

To date, various predictive models for high strength concrete (HSC) have been proposed that are capable of generating complete stress-strain curves. These models were validated for HSC prepared with and without silica fume. In this paper, an investigation on these predictive models has been presented by applying them on two different series of HSC. The first series of HSC was prepared by utilizing 100% cement content, while second series was prepared by utilizing 90% cement and 10% Metakaolin. The compressive strength of the concrete was ranged from 71-87 MPa. For each series of HSC, total four cylinders of the size 100×200mm were cast to obtain the stress-strain curves at 28 days.It has been found that the pattern of the stress-strain curve of each cylinder among four cylinders of each series was different from other, in spite of preparing from the similar batch. When predictive models were applied to these cylinders using their test data then it was found that all models more or less deficient to accurately predict the stress-strain behavior.

Experimental Research on the Stress - Strain Curve of Regional Confined Concrete under Single Axial Press

2014 ◽  
Vol 584-586 ◽  
pp. 1289-1292
Author(s):  
Guo Liang Zhu
Keyword(s):  
Mechanical Properties ◽  
Theoretical Analysis ◽  
Constitutive Model ◽  
Theoretical Basis ◽  
Strain Curve ◽  
Confined Concrete ◽  
Constitutive Relationship ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Relationship Of

Regional confined concrete is base on confined concrete. It is the theory and application of a new attempt and development on confined concrete. To apply it to the actual project, we need to research mechanical properties and establish constitutive relationship of regional confined concrete. According to the research, we had carried on a series of tests, founded the stress-strain constitutive model of regional confined concrete under single axial press. The accuracy of theoretical analysis were more fully verified , and a theoretical basis for the application was provided.

Evaluation of Anisotropic Pipe Steel Stress-Strain Relationships Influence on Strain Demand

2012 ◽  
Author(s):  
James D. Hart ◽  
Nasir Zulfiqar ◽  
Joe Zhou
Keyword(s):  
Strain Hardening ◽  
Pipe Steel ◽  
High Strain ◽  
Strain Curve ◽  
High Strength ◽  
Strain Response ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Hardening Modulus ◽  
Strain Relationship

Buried pipelines can be exposed to displacement-controlled environmental loadings (such as landslides, earthquake fault movements, etc.) which impose deformation demands on the pipeline. When analyzing pipelines for these load scenarios, the deformation demands are typically characterized based on the curvature and/or the longitudinal tension and compression strain response of the pipe. The term “strain demand” is used herein to characterize the calculated longitudinal strain response of a pipeline subject to environmentally-induced deformation demands. The shape of the pipe steel stress-strain relationship can have a significant effect on the pipe strain demands computed using pipeline deformation analyses for displacement-controlled loading conditions. In general, with sufficient levels of imposed deformation demand, a pipe steel stress-strain curve with a relatively abrupt or “sharp” elastic-to-plastic transition will tend to lead to larger strain demands than a stress-strain curve with a relatively rounded elastic-to-plastic transition. Similarly, a stress-strain curve with relatively low strain hardening modulus characteristics will tend to lead to larger strain demands than a stress-strain curve with relatively high strain hardening modulus characteristics. High strength UOE pipe can exhibit significant levels of anisotropy (i.e., the shapes of the stress-strain relationships in the longitudinal tension/compression and hoop tension/compression directions can be significantly different). To the extent that the stress-strain curves in the different directions can have unfavorable shape characteristics, it follows that anisotropy can also play an important role in pipeline strain demand evaluations. This paper summarizes a pipeline industry research project aimed at evaluation of the effects of anisotropy and the shape of pipe steel stress-strain relationships on pipeline strain demand for X80 and X100 UOE pipe. The research included: a review of pipeline industry literature on the subject matter; a discussion of pipe steel plasticity concepts for UOE pipe; characterization of the anisotropy and stress-strain curve shapes for both conventional and high strain pipe steels; development of representative analytical X80 and X100 stress-strain relationships; and evaluation of a large matrix of ground-movement induced pipeline deformation scenarios to evaluate key pipe stress-strain relationship shape and anisotropy parameters. The main conclusion from this work is that pipe steel specifications for high strength UOE pipe for strain-based design applications should be supplemented to consider shape-characterizing parameters such as the plastic complementary energy.

Polypropylene Fiber Reinforced Concrete for Airfield Pavements:Modeling of Stress-Strain Curve Under Compression

2011 ◽  
Vol 261-263 ◽  
pp. 171-177
Author(s):  
Tammam Merhej ◽  
De Cheng Feng
Keyword(s):  
Reinforced Concrete ◽  
Analytical Model ◽  
Volume Fraction ◽  
Polypropylene Fiber ◽  
Strain Curve ◽  
Fiber Reinforced Concrete ◽  
Fiber Reinforced ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Polypropylene Fiber Reinforced Concrete

An analytical model for compressive stress-strain curve of polypropylene fiber reinforced concrete (PPFRC) was proposed. The polypropylene fiber used was 60-mm long twisted fiber with aspect ratio of 120. The fiber was added in three volume fractions 0.2%, 0.4% and 0.6%. Tow concrete mixtures with varying water-cement ratio were used. The accuracy of the proposed model was evaluated by comparing the area under stress-strain curves for experimental and analytical model. The results showed good agreement between the experimental and analytical curves. In addition; empirical equations were proposed to quantify the effect of polypropylene fiber on compressive strength, strain at peak stress, and toughness of concrete in terms of fiber volume fraction.

Experimental Research on Stress-Strain Curve of Carbon Fiber Reinforced Concrete

2013 ◽  
Vol 668 ◽  
pp. 640-644 ◽  
Author(s):  
Xiao Chu Wang ◽  
Jun Wei Wang ◽  
Hong Tao Liu
Keyword(s):  
Reinforced Concrete ◽  
Carbon Fiber ◽  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Strain Curve ◽  
Fiber Reinforced Concrete ◽  
Experimental Results ◽  
Stress Strain Curve ◽  
Fiber Volume ◽  
Stress Strain

In order to further investigate the stress-strain curve of carbon fiber reinforced concrete, the curve of stress-strain is used segmentation tabulators on the basis of the existing tests. Based on the axial compression experiments of 9 carbon fiber concrete reinforced samples filled with different carbon fiber admixture amounts, the theoretical calculating formula of the stress-strain curve with different admixture amounts was proposed, and the theoretical formula of calculation parameters and carbon fiber volume fraction was putted forward. The experimental results show that the calculation parameters of the stress-strain curve increases with the increase of the carbon fiber admixture amounts. The theoretical calculating formula of the peak strain and carbon fiber volume fraction, the compressive strength, and the calculated results agreed well with the experimental results.

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