Reinforcement strength, ductility and bendability properties are important components in the design of reinforced concrete members, as the strength of any member comes mainly from reinforcement. Strain compatibility and plastic behaviours’ are mainly depending on reinforcement ductility. In construction practice, often welding of the bars is required. Welding of reinforcement is an instant solution in many cases, whereas welding is not a routine connection process. Welding will cause deficiencies in reinforcement bars, metallurgical changes and recrystallization of the microstructure of particles. Weld metal toughness is extremely sensitive to the welding heat input that decreases both its strength and ductility.

1. WELCOME TO
OUR THESIS
PRESENTATION

2. Course Code: CE 400
Course Name: Project & Thesis

3. THESIS TITLE
Established a relationship between weld
splice length and diameter of the
reinforcing bar

4. PRESENTED BY (GROUP:02)
NURMOHAMMAD (47)
MD. AKTARUL ISLAM (12)
MOKLESUR RAHMAN (38)
MD. NAZMUS SAKIB (46)
MD. SAZIB MIAH (54)
SUPERVISOR
MD. AKTER HOSSAIN
Lecturer
Department of Civil Engineering
Dhaka International University

5. PRESENTATION CONTENT
Introduction
Literature Review
Objectives
Methodology
Data Table
Test Result
Conclusion
Recommendation
Reference

6. INTRODUCTION
Reinforcement strength, ductility and bendability properties are important components
in the design of reinforced concrete members, as the strength of any member comes
mainly from reinforcement. Strain compatibility and plastic behaviors’ are mainly
depending on reinforcement ductility. In construction practice, often welding of the
bars is required. Welding of reinforcement is an instant solution in many cases,
whereas welding is not a routine connection process. Welding will cause deficiencies
in reinforcement bars, metallurgical changes and recrystallization of the
microstructure of particles. Weld metal toughness is extremely sensitive to the welding
heat input that decreases both of its strength and ductility.

7. LITERATURE REVIEW
Ghafur H. Ahmed (2015) show that strength and elongation of
the welded bars decreased by (10-40%) and (30-60%)
respectively. Cold bending of welded bars and groove welds shall
be prevented.
Denise Stefania Sanchez Contreras (2014) show that The
tensile resistance of the lap spliced bars in the double pullout
specimens was measured directly. The contact lap splices with a
150mm, 200mm, and 250 mm lap splice length developed
approximately 38%, 35% and 29% of the theoretical yield load of
the reinforcement, respectively.

8. OBJECTIVES
 Improvement in the structural continuity between bars,
generating greater security.
 Possibility of joining bars of any length and diameter.

9. The working methodology of the study is as follows:
i. Selection of materials.
ii. Collect different diameter rods.
iii. Preparation of specimen.
iv. Weld same diameter rod.
v. Braking strength test by the UTM machine.
vi. Result and discussion.
vii. Conclusion and recommendation.
METHODOLOGY

10. METHODOLOGY
Mild steel rod Welding electrode rod
Circular saw Lapping Welding

11. S.N
Lapping
(in)
Area
(mm2
)
Ultimate
Load (kN)
Calibrated
Load (kN)
Load in N
Average
load in N
Ultimate
Strength
(MPa)
Yield
Strength
(MPa)
Weld
Strength
(MPa)
1
1 78.50
34 69.47 69472.40
69472.40 885.00 665.41 665.41
2 33 68.33 68329.30
3 35 70.62 70615.50
4
2 78.50
50 87.76 87762.00
88143.03 1122.84 844.24 844.24
5 51 88.91 88905.10
6 50 87.76 87762.00
7
4 78.50
50 87.76 87762.00
89667.17 1142.26 858.84 858.84
8 53 91.19 91191.30
9 52 90.05 90048.20
10
5 78.50
48 85.48 85475.80
88143.03 1122.84 844.24 844.24
11 50 87.76 87762.00
12 53 91.19 91191.30
13
6 78.50
50 87.76 87762.00
88524.07 1127.70 847.89 847.89
14 54 92.33 92334.40
15 48 85.48 85475.80
DATA TABLE
Sample-A (10mm diameter MS Bar)

12. S.N
Lapping
(in)
Area
(mm2
)
Ultimate
Load (kN)
Calibrated
Load (kN)
Load in N
Average
load in N
Ultimate
Strength
(MPa)
Yield
Strength
(MPa)
Weld
Strength
(MPa)
1
1 113.04
40 76.33 76331.00
76712.03 678.63 510.25 510.25
2 38 74.04 74044.80
3 43 79.76 79760.30
4
2 113.04
52 90.05 90048.20
93477.50 826.94 621.76 621.76
5 58 96.91 96906.80
6 55 93.48 93477.50
7
4 113.04
76 117.48 117482.60
116339.50 1029.19 773.83 773.83
8 74 115.20 115196.40
9 75 116.34 116339.50
10
5 113.04
77 118.63 118625.70
117101.57 1035.93 778.89 778.89
11 75 116.34 116339.50
12 75 116.34 116339.50
13
6 113.04
78 119.77 119768.80
117863.63 1042.67 783.96 783.96
14 76 117.48 117482.60
15 75 116.34 116339.50
Sample-B (12mm diameter MS Bar)
DATA TABLE

13. S.N
Lapping
(in)
Area
(mm2
)
Ultimate
Load (kN)
Calibrated
Load (kN)
Load in N
Average
load in N
Ultimate
Strength
(MPa)
Yield
Strength
(MPa)
Weld
Strength
(MPa)
1
1 200.96
58 96.91 96906.80
98430.93 489.80 368.27 368.27
2 60 99.19 99193.00
3 60 99.19 99193.00
4
2 200.96
90 133.49 133486.00
133867.03 666.14 500.86 500.86
5 88 131.20 131199.80
6 93 136.92 136915.30
7
4 200.96
122 170.07 170065.20
167779.00 834.89 627.73 627.73
8 120 167.78 167779.00
9 118 165.49 165492.80
10
5 200.96
123 171.21 171208.30
170827.27 850.06 639.14 639.14
11 120 167.78 167779.00
12 125 173.49 173494.50
13
6 200.96
120 167.78 167779.00
168541.07 838.68 630.59 630.59
14 120 167.78 167779.00
15 122 170.07 170065.20
Sample-C (16mm diameter MS Bar)
DATA TABLE

14. S.N
Lapping
(in)
Area
(mm2
)
Ultimate
Load (kN)
Calibrated
Load (kN)
Load in N
Average
load in N
Ultimate
Strength
(MPa)
Yield
Strength
(MPa)
Weld
Strength
(MPa)
1
1 314.00
72 112.91 112910.20
111005.03 353.52 265.80 265.80
2 70 110.62 110624.00
3 69 109.48 109480.90
4
2 314.00
107 152.92 152918.70
152537.67 485.79 365.25 365.25
5 105 150.63 150632.50
6 108 154.06 154061.80
7
4 314.00
158 211.22 211216.80
216170.23 688.44 517.62 517.62
8 166 220.36 220361.60
9 163 216.93 216932.30
10
5 314.00
177 232.94 232935.70
236365.00 752.75 565.98 565.98
11 183 239.79 239794.30
12 180 236.37 236365.00
13
6 314.00
180 236.37 236365.00
237127.07 755.18 567.81 567.81
14 180 236.37 236365.00
15 182 238.65 238651.20
Sample-D (20mm diameter MS Bar)
DATA TABLE

15. TEST RESULT
Weld Strength vs lapping 10 mm diameter rod Weld Strength vs lapping 12 mm diameter rod
Weld Strength vs lapping 16 mm diameter rod Weld Strength vs lapping 20 mm diameter rod

16. The graph shows weld Strength vs lapping. It is seen the weld
strength increase with the increase of lapping. More precisely
it is seen that the lowest weld strength when lapping minimum
and weld strength highest than lapping maximum.
TEST RESULT

17. 1
2
3
4
5
6
10 12 16 20
Lapping
Length
(inch)
Diameter (mm)
TEST RESULT
Diameter
(mm)
lapping
Length
(inch)
lapping
Length
(cm)
10 2 5.08
12 4 10.16
16 4 10.16
20 5 12.70
Lapping Length vs diameter of steel bar
Lapping length for different diameter bar

18. TEST RESULT
Lapping length = 0.7 X Diameter of rod in mm
Example
Lapping length for 10 mm diameter rod.
Lapping length = 0.7 X 10
= 7 cm
Lapping length for 16 mm diameter rod.
Lapping length = 0.7 X 16
= 11.2 cm
≈ 12 cm
Diameter
(mm)
Lapping
Length
(inch)
Lapping
Length
(cm)
10 2 5.08
12 4 10.16
16 4 10.16
20 5 12.70

19. TEST RESULT
Lapping length = 0.7 X Diameter of rod in mm
Example
Lapping length for 10 mm diameter rod.
Lapping length = 0.5 X 10
= 5 cm < 5.08 cm
Lapping length for 12 mm diameter rod.
Lapping length = 0.5 X 12
= 6 cm < 10.16 cm
Example
Lapping length for 16 mm diameter rod.
Lapping length = 0.5 X 16
= 8 cm < 10.16 cm
Lapping length for 20 mm diameter rod.
Lapping length = 0.5 X 20
= 10 cm < 12.70 cm

20. TEST RESULT
Lapping length = 0.7 X Diameter of rod in mm
Example
Lapping length for 10 mm diameter rod.
Lapping length = 0.6 X 10
= 6 cm > 5.08 cm
Lapping length for 12 mm diameter rod.
Lapping length = 0.6 X 12
= 7.2 cm < 10.16 cm
Example
Lapping length for 16 mm diameter rod.
Lapping length = 0.6 X 16
= 9.6 cm < 10.16 cm
Lapping length for 20 mm diameter rod.
Lapping length = 0.6 X 20
= 12 cm < 12.70 cm

21. CONCLUSION
 When the diameter of the reinforcing bar 10mm, 12mm and
length of lapping is 1 inch the most of specimens fail in the
lapping zone due failure of lapping before reaching its full
tensile strength in that minimum length of lapping should be 2
inch.
 For larger diameter of the larger will be lapping length.
 For 12mm to 16mm diameter bar the minimum length of
lapping should be 3 inch.
 For 16mm to 20mm diameter bar the minimum length of
lapping should be 5 inch.
 Finally, lapping length = 0.7 X Diameter of rod in mm

22. RECOMMENDATION
 Number of specimen may be increased.
 Automatic dial reader may be used to reduce the percentage
of error.
 Provide different types of joints.
 Lapping increases or decrease.

23.  Hoque M. M., Islam N. and Mohammed, (2013), “Review of design codes
for tension splice length for reinforced concrete members”, Journal of
Civil Engineering (IEB), 41(2), pp 161-177
 Stefania Sanchez Contreras Denise, (2014), “The Effect of Splice Length
and Distance between Lapped Reinforcing Bars in Concrete Block
Specimens”, Master of Scienc Thesis, University of Saskatchewan
 H. Ahmed Ghafur, (2015) “Mechanical Properties of Welded Deformed
Reinforcing Steel Bars”, Zanco Journal of Pure and Applied Sciences,
(27) pp 99-112
REFERENCE

24. Thanks To All