scholarly journals Structural Behavior of Unbalanced Section self-compacting reinforced concrete axially Loaded columns

2018 ◽  
Vol 7 (4.37) ◽  
pp. 127
Author(s):  
Aamer Najim Abbas ◽  
Nura Jasim Muhammed
Keyword(s):  
Reinforced Concrete ◽  
Large Deformations ◽  
Concrete Columns ◽  
Element Model ◽  
Asymmetric Distribution ◽  
Reinforcing Steel ◽  
Test Results ◽  
Normal Concrete ◽  
Steel Bars ◽  
Control Column

Eight (120 mm) square and (1 m) long reinforced concrete columns were tested under axial load to large inelastic deformations. The main purpose of this research was to investigate the behavior of column sections confined by rectilinear ties. Major variables considered in this program included: (1) Distribution of longitudinal and lateral steel, including unbalanced section due to the asymmetric distribution of reinforcing steel bars (2) type of concrete; normal concrete and self-compacting concrete. Finite element model was performed to validate the experimental results of this investigation. Test results indicate that a asymmetric distribution longitudinal bars results in desired performance of columns. Unsupported longitudinal bars and its number effective only at large deformations and result in rapid deterioration of column behavior at a later stage. There is 8.75% and 35.65% decrease in ultimate capacity under the control column, asymmetric distribution of reinforcing steel bars appears a more brittle while symmetric bars yields more elastic than brittle, it adds safety when failure happens.   

Nonlinear Analysis on Stainless Steel Reinforced Concrete Columns under Low-Cyclic Load

2012 ◽  
Vol 256-259 ◽  
pp. 588-591
Author(s):  
Guo Xue Zhang ◽  
Chang Wei Wang ◽  
Jia Wei Huang
Keyword(s):  
Stainless Steel ◽  
Reinforced Concrete ◽  
Cyclic Load ◽  
Concrete Columns ◽  
Element Model ◽  
Test Results ◽  
Earthquake Simulation ◽  
Reinforced Concrete Columns ◽  
Static Test ◽  
Steel Reinforced Concrete

In order to study the elastic-plastic mechanics properties of the stainless steel reinforced concrete columns under low-cyclic load, the engineering open-source earthquake simulation system OpenSees is used to carry out the numerical simulation. The comparison between the computed results and the pseudo-static test results shows that the OpenSees may stimulate the mechanical properties of the stainless steel reinforced concrete columns by using the fiber element model, both of the skeleton curves and hysteretic curves are well agreement with the tests results.

scholarly journals Experimental Investigation into Corrosion Effect on Mechanical Properties of High Strength Steel Bars under Dynamic Loadings

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Hui Chen ◽  
Jinjin Zhang ◽  
Jin Yang ◽  
Feilong Ye
Keyword(s):  
Mechanical Properties ◽  
Strain Rate ◽  
Dynamic Loading ◽  
High Strength Steel ◽  
High Strength ◽  
Tensile Tests ◽  
Reinforcing Steel ◽  
Test Results ◽  
Cross Sectional ◽  
Steel Bars

The tensile behaviors of corroded steel bars are important in the capacity evaluation of corroded reinforced concrete structures. The present paper studies the mechanical behavior of the corroded high strength reinforcing steel bars under static and dynamic loading. High strength reinforcing steel bars were corroded by using accelerated corrosion methods and the tensile tests were carried out under different strain rates. The results showed that the mechanical properties of corroded high strength steel bars were strain rate dependent, and the strain rate effect decreased with the increase of corrosion degree. The decreased nominal yield and ultimate strengths were mainly caused by the reduction of cross-sectional areas, and the decreased ultimate deformation and the shortened yield plateau resulted from the intensified stress concentration at the nonuniform reduction. Based on the test results, reduction factors were proposed to relate the tensile behaviors with the corrosion degree and strain rate for corroded bars. A modified Johnson-Cook strength model of corroded high strength steel bars under dynamic loading was proposed by taking into account the influence of corrosion degree. Comparison between the model and test results showed that proposed model properly describes the dynamic response of the corroded high strength rebars.

scholarly journals Experimental analysis of reinforced concrete columns strengthened with self-compacting concrete and connectors

2012 ◽  
Vol 5 (3) ◽  
pp. 305-315
Author(s):  
P. P. Nascimento ◽  
R. B. Gomes ◽  
L. L. J. Borges ◽  
D. L. David
Keyword(s):  
Reinforced Concrete ◽  
Failure Mode ◽  
Experimental Analysis ◽  
Thick Layer ◽  
Concrete Columns ◽  
The Other ◽  
Experimental Phase ◽  
Self Compacting Concrete ◽  
Reinforced Concrete Columns ◽  
Steel Bars

There are many problems involving cases of destruction of buildings and other structures. The columns can deteriorate for several reasons such as the evolution and changing habits of the loads. The experimental phase of this work was based on a test involving nine reinforced concrete columns under combined bending and axial compression, at an initial eccentricity of 60 mm. Two columns were used as reference, one having the original dimensions of the column and the other, monolithic, had been cast along the thickness of the strengthened piece. The remaining columns received a 35 mm thick layer of self-compacting concrete on their compressed face. For the preparation of the interface between the two materials, this surface was scarified and furrowed and connectors were inserted onto the columns' shear reinforcement in various positions and amounts.As connectors, 5 mm diameter steel bars were used (the same as for stirrups), bent in the shape of a "C" with 25 mm coatings. >As a conclusion, not only the quantity, but mainly, the location of the connectors used in the link between substrate and reinforcement is crucial to increase strength and to change failure mode.

scholarly journals Experimental analysis of reinforced concrete columns strengthened with Self-Compacting concrete

2010 ◽  
Vol 3 (3) ◽  
pp. 271-283 ◽  
Author(s):  
M. Y. M. Omar ◽  
R. B. Gomes ◽  
A. P. A. Reis
Keyword(s):  
Reinforced Concrete ◽  
Ultimate Load ◽  
Rectangular Cross Section ◽  
Concrete Columns ◽  
Loading Capacity ◽  
Longitudinal Reinforcement ◽  
Self Compacting Concrete ◽  
Reinforced Concrete Columns ◽  
Subsequent Test ◽  
Steel Bars

This paper presents the results of reinforced concrete columns strengthened by addition of a self-compacting concrete overlay at the compressed and at the tensioned face of the member, with and without addition of longitudinal steel bars. Eight columns were submit- ted to loading with an initial eccentricity of 60 mm . These columns had 120 mm x 250 mm of rectangular cross section, 2000 mm in length and four longitudinal reinforcement steel bars with 10 mm in diameter. Reference columns P1 and P2 were tested to failure without any type of rehabilitation. Columns P3 to P8 were loaded to a predefined load (close to the initial yield point of tension reinforce- ment), then unloaded and strengthened for a subsequent test until failure. Results showed that the method of rehabilitation used was effective, increasing the loading capacity of the strengthened pieces by 2 to 5 times the ultimate load of the reference column.

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 Ductility Estimation of Concrete Beams Longitudinally Reinforced with Hybrid FRP-Steel Bars

2022 ◽  
Author(s):  
Rendy Thamrin ◽  
Zaidir Zaidir ◽  
Devitasari Iwanda
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beams ◽  
Element Model ◽  
Neutral Axis ◽  
Reinforced Concrete Beams ◽  
Flexural Behavior ◽  
Bending Test ◽  
Longitudinal Reinforcement ◽  
Steel Bars ◽  
Hybrid Reinforcement

An experimental study was carried out to evaluate the ductility of reinforced concrete beams longitudinally reinforced with hybrid FRP-Steel bars. The specimens were fourteen reinforced concrete beams with and without hybrid reinforcement. The test variables were bars position, the ratio of longitudinal reinforcement, and the type of FRP bars. The beams were loaded up to failure using a four-point bending test. The performance of the tested beams was observed using the load-deflection curve obtained from the test. Numerical analysis using the fiber element model was used to examine the growth of neutral axis depth due to the effect of test variables. The neutral axis curves were then used to further estimate the neutral axis angle and neutral axis displacement index. The test results show that the position of the reinforcement greatly influences the flexural behavior of the beam with hybrid reinforcement. It was observed from the test that the flexural capacity of beams with hybrid reinforcement is 4% to 50% higher than that of the beams with conventional steel bars depending on bars position and the ratio of longitudinal reinforcement. The ductility decreases as the hybrid reinforcement ratio (Af/As) increases. This study also showed that a numerical model developed can predict the flexural behavior of beams with hybrid reinforcement with reasonable accuracy.

scholarly journals Experimental investigation on the potentials of Sisal Fibres as Reinforcements for Drainage Concrete Cover Plates

2020 ◽  
Vol 3 (1) ◽  
Author(s):  
Leopold Mbereyaho ◽  
Francois Twayigize ◽  
Laury Givens Musabe Ishimwe ◽  
Sandrine Mutumwinka
Keyword(s):  
Reinforced Concrete ◽  
Concrete Cover ◽  
Test Results ◽  
Flexural Members ◽  
Steel Bars ◽  
Drainage Channels ◽  
Concrete Plates ◽  
Agave Sisalana ◽  
Cover Plates

With the development of infrastructures in Rwanda, the roads construction has been one of busiest area, and as the country counts thousands hills the design and construction of drainage systems required a great attention. Most of road drainage channels are covered with concrete plates that are reinforced with ordinary steel bars, while others are not covered due to the high cost of reinforced concrete plates. As the majority of these  plates are only subjected to light pedestrian loads, they should be reinforced accordingly. This study was intended to check the potentials of sisal fibres from Agave Sisalana’ cactus plant which has shown good results in flexural members, as plates reinforcements. At first the quality of ordinary concrete components was checked. Then some of sisal fibres were prepared, manufactured into ropes of 10 mm diameter and then used as replacements of main steel bars in concrete plates before their tensile capacity was checked. Other pieces of sisal fibres of 5 cm length were mixed in concrete mass with different percentages of 0.5%, 1% and 1.5% of concrete volume. Test results showed that the compressive, tensile and flexural strengths for concrete with 1% of sisal fibres were more adequate for M30 concrete and therefore able of sustaining the real loads applied to the  drainage concrete cover plates. As the performance of natural sisal fibres depends on fibres treatment methods, length, and type of required concrete, further studies on the use of sisal fibres should consider those factors. Keywords: Agave sisalana, drainage channel, Reinforced Concrete, Sisal Fibres, Sisal ropes.

Sign in / Sign up

Export Citation Format

Share Document