Behavior of RC Columns Confined with Welded Wire Mesh and Chicken Mesh

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Behavior of RC Columns Confined with Welded Wire Mesh and Chicken Mesh

Vaibhav S. Riswadkar1, Dr. C. P. Pise2, G.D. Lakade3

1P.G. Student, Department of Civil Engineering, SKNSCOE, Pandharpur, Maharashtra, India

2Head of Department of Civil Engineering, SKNSCOE, Pandharpur, Maharashtra, India

3Assistant Professor, Department of Civil Engineering, SKNSCOE, Pandharpur, Maharashtra, India

Abstract – It is uneconomical to design a structure to respond in the elastic range to the earthquake induced inertial forces, so it is required to design the structures so that the energy are often dissipated by post elastic deformation of the members which needs certain elements to be designed for ductility also as strength. To avoid the formation of the plastic hinges within the column most of the codes prefer strong column and weak beam theory hence the reinforcement within the column should be carefully designed. The transverse reinforcement has an important role in the ductility of the column. For the formation of the plastic hinges in column it requires confinement of concrete by providing the transverse reinforcement.

This paper deals with the effect of confinement reinforcement, its material, understanding the combination of confinement reinforcement and also the load carrying capacity of the R.C. rectangular column. The study of rectangular column is critical because it is employed mostly within the practical building construction and also the confinement reinforcement design for the column with square and circular cross section has proven simpler as compared to the R.C. rectangular column.

Keywords – WWM, rectangular column, confinement

INTRODUCTION:

It is uneconomical to design structure to respond in the elastic range, for earth quick force, so because of this it is necessary to design structure so that energy can be dissipated by post elastic deformation of members it is required to design important structural element for ductility as well as strength. We know that ductile behaviour of concrete section can be attended by transverse

reinforcement, which improves the property of concrete by confining it. From various case studies, it is observed that, failure of the entire structure was triggered by the failure of column by chain action, so it is important to improve effectiveness of column.

In this research experiment was conducted to examine structural performance of reinforced of concrete column confine with welded wire mesh and combination of welded wire mesh with chicken mesh, nine strut column with different confinement, in which three of each category were tested under UTM (Universal Testing Machine) by gradually varying load on it the various parameters which are obtained are comparing with each other like, cost ratio, stress, strain, load carrying capacity, feasibility of work etc.

CONCLUDING REMARK OF LITERATURE:

Realizing the fact, Rectangular column have been extensively used whenever circular, square could not mostly used in a practice. And most of the research work has been done on circular or square column.

DETAILS OF SPECIMEN:

Table 1: Details of Specimen.

Type of column

Dimensions

Conventional Reinforcement

Confinement Reinforcement

No. of Column Casted

Column with Conventional Reinforcement

230X150

(Rectangular)

4#12mm(Fe500)

Longitudinal Bars 6@125mm c/c (Fe250)

Nil

03

Column with Conventional Reinforcement and Welded Wire Mesh

230X150

(Rectangular)

4#12mm(Fe500)

Longitudinal Bars 6@125mm c/c (Fe250)

Welded Wire Mesh With 1(25mm) Spaced Grids

03

Column with Conventional Reinforcement, Welded Wire Mesh and Chicken Mesh

230X150

(Rectangular)

4#12mm(Fe500)

Longitudinal Bars 6@125mm c/c (Fe250)

Welded Wire Mesh With 1(25mm) Spaced Grids And Chicken Mesh With 0.5(12.5mm) Spaced Grids

03

Fig: 1 Arrangement Of Conventional Reinforcement

Fig: 2 Arrangement Of Conventional Reinforcement With Welded Wire Mesh

Fig: 3 Arrangement Of Conventional Reinforcement With Welded Wire Mesh And Chicken Mesh

CONFIGURATIONS ADOPTED FOR THE COMPARATIVE RESULTS:

  • For each of the configuration 3 columns will be casted to obtain the average results and achieve the accuracy.

  • Column without confinement.

  • Column with confinement reinforcement as welded wire mesh.

  • Column with confinement reinforcement as chicken mesh.

EXPERIMENTAL SETUP:

In experimentation, 09 no of specimens are prepared and these are tested under loading conditions. Specimens of RCC structure are subjected to compressive type of loading. Specimen is loaded in universal testing machine. The testing was carried out in the UTM having capacity of 100 ton. Before applying the load the vertical position of column was checked using spirit level. Specimen is loaded vertically for testing compressive strength. Gradually, fluid pressure is applied through hydraulic pump. Response of the specimen under loading is sensed by load cell and it is

recorded in system. Also the deflection on each face of specimen is observed on dial gauge which is fixed on each face of the specimen [4].

Fig: 4 Experimental Set-Up For Testing And Measuring Deflection

RESULTS AND DISCUSSIONS:

Strength comparison

According to the test results the various parameters are compared to the column with conventional reinforcement. The objectives which are to study the effect of

confinement reinforcement, therefore various parameters obtained from the test such as Compressive strength of column, Lateral buckling, Vertical deflection. Following tables shows the comparison of the test results.

Table 2: Details of Results.

577.9

Configuration

Specimen

Occurrence of First Crack (KN)

Ultimate Load (KN)

Max Vertical Deflection (mm)

Max Lateral Deflection(mm) & Strain

Column with Conventional Reinforcement

CR1

320

CR2

300

387.20

11.5

0.7@ Face B

CR3

290

369.30

11.8

0.73@ Face C

Average

303.33

378.25

11.65

Column with Conventional Reinforcement& Welded Wire Mesh

CRW1

440.00

655.00

10.8

0.5@ Face C

CRW2

432.22

649.20

8.6

0.52@ Face B

CRW3

438.00

639.00

9.6

0.78@ Face A

Average

436.74

647.73

9.67

Column with Conventional Reinforcement, Welded Wire Mesh& Chicken Mesh

CRWC1

360

6.1

0.57@ Face B

CRWC2

380

543.2

6.8

0.62@ Face A

CRWC3

400

567.9

6.2

0.66@ Face A

Average

380

563.00

6.37

COST COMPARISON:

Due to the confinement reinforcement in the Column there is an increase in the Strength but also the cost is increased correspondingly. It is needed to study the

increase in the cost with respect to the strength of column. For estimation of cost required per columns in each configuration the rates of the material are surveyed according to Market. Also the quantities

required for the columns are calculated so that the cost per column is estimated and can be compared with

column with conventional reinforcement.

Increase in cost with reference to Conventional Column:

Table 3: Details of Cost Comparison.

Sr. No.

Type of confinement

Cost required for one column In Rs.

Difference

% difference

Remark

1

Conventional Reinforcement

679

2

Conventional Reinforcement & welded wire mesh

752

73

10.75

10.75%

increase in cost

3

Conventional Reinforcement, welded wire mesh & chicken mesh

780

101

14.87

14.87%

increase in cost

Referring above table it is evident that the cost required with reference to column with conventional reinforcement is more for other two configurations. Column with Conventional Reinforcement, &welded wire mesh & chicken mesh, which is larger than other configuration.

Following are the conclusions derived from the experiments conducted on columns with and without Confinement:

  1. It is observed that for the Column with Confinement Reinforcement there is an increase in strength as compared to the column with Conventional reinforcement. For column with Welded wire mesh (CRW) the strength is increased by 71.24 % and for column with Confinement reinforcement as Welded wire mesh and Chicken Mesh (CRWC) it is 48.84 % increased. .

  2. It has also observed that there is an increase in the ductility of the column due to the use of confinement reinforcement. As measured, the column with conventional reinforcement the average vertical deformation is 11.65 mm which has reduced for other two configurations of columns (CRW & CRWC) is about 17 to 45% .

  3. According to the strength criteria it can be stated that the column with Conventional Reinforcement and welded wire mesh resists more load.

REFERENCES:

  1. Subramanian N (2011) Design of Confinement Reinforcement for RC columns The Indian Concrete Journal (ICJ).

  2. Loring ADetailing reinforced concrete columns for seismic performance.

  3. Shetty R.K. and Jain A.K., Special confinement reinforcement in RC

  4. 4. Paultre, P. and Légeron,., Confinement reinforcement design for Reinforced concrete columns, Journal of Structural Engineering, ASCE, Vol.134, No.5, May 2008, pp.738-749.

  5. 5. ACI 318:2008, Building Code Requirements for Structural Concrete, American Concrete Institute, Farmington Hills, Michigan, 2008, p. 437.

  6. 6. Georgios Kostantakopoulos, Stathis Bousias. (2004). Experimental study of effect of confinement on the RC column 13th World Conference on Earthquake EngineeringVancouver, B.C., Canada, Paper No. 770.

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  11. 11. Pantazopoulou, S. Detailing for reinforcement stability in RC members Journal of Structural Engineering, ASCE, 1998; 124(6): 623-632.

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