Shear strengthening of reinforced concrete beams using fibre reinforced polymer composites

Iyappan, Rajamony; Murugan, Madasamy

doi:10.1590/1517-7076-rmat-2024-0013

Rajamony Iyappan

V V College of Engineering, Civil Engineering Department. 627657, Tisaiyanvilai, Tamilnadu, India.

https://orcid.org/0009-0000-4791-8431

Madasamy Murugan

Government College of Engineering, Civil Engineering Department. 627007, Tirunelveli, Tamilnadu, India.

*

Corresponding Author: Rajamony Iyappan, e-mail: iyappan.vin@gmail.com, murugan@gcetly.ac.in

Figures (20)
Tables (14)

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Figure 1
Reinforcement details of flexure deficient beams.

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Figure 2
Reinforcement details of shear deficient beams.

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Figure 3
Placing of reinforcemet in the mould.

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Figure 4
Casting of specimen.

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Figure 5
Demoulding of specimen.

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Figure 6
Test setup of conventional beam.

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Figure 7
Test setup of basalt fibre wrapped beams.

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Figure 8
Test setup of glass fibre wrapped beams.

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Figure 9
Failure of conventional shear deficient RC beams.

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Figure 10
Failure of BFRP strengthened shear deficient RC beams.

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Figure 11
Failure of GFRP strengthened shear deficient RC beams.

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Figure 12
Ultimate load of conventional, basalt fibre and glass fibre under static loading.

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Figure 13
Load vs displacement curve of static loading in shear deficient RC beams.

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Figure 14
Ultimate load of conventional, basalt fibre and glass fibre under static loading.

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Figure 15
Load vs displacement curve of cyclic loading in shear deficient conventional RC beam.

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Figure 16
Load vs displacement curve of cyclic loading in shear deficient BFRP strengthened RC beam.

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Figure 17
Load vs displacement curve of cyclic loading in shear deficient GFRP strengthened RC beam.

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Figure 18
Load vs displacement curve.

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Figure 19
Stiffness curve.

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Figure 20
Energy dissipation curve.

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Table 1
Properties of cement.

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Table 2
Properties of fine and coarse aggregate.

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Table 3
Properties of steel bars.

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Table 4
Properties of fibres.

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Table 5
Properties of Nitowrap 410 saturant.

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Table 6
Properties of FRP materials.

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Table 7
Compressive strength of FRP confined concrete cubes.

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Table 8
Compressive strength of FRP confined concrete cylinders.

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Table 9
Flexural strength of FRP confined concrete prisms.

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Table 10
Results of the static loading in shear deficient RC beams.

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Table 11
Ultimate strength of shear deficient RC beams under cyclic loading.

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Table 12
Results of the cyclic loading in conventional shear deficient RC beam.

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Table 13
Results of the cyclic loading in BFRP strengthened shear deficient RC beam.

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Table 14
Results of the cyclic loading in GFRP strengthened shear deficient RC beam.

SL. NO.	TESTS PERFORMED	RESULTS	SL.NO.	TESTS PERFORMED	RESULTS
1	Standard consistency	30 percent	5	Fineness (<90 microns)	5 percent
2	Initial setting time	48 minutes	6	3^rd day compressive strength of cement	30.0 N/mm²
3	Final setting time	310 minutes	7	7^th day compressive strength of cement	42.0 N/mm²
4	Specific gravity	3.14	8	28^th day compressive strength of cement	58.5 N/mm²

SL. NO.	PROPERTY	FINE AGGREGATE	COARSE AGGREGATE
1	Specific gravity	2.67	2.72
2	Fineness modulus	2.62	6.70
3	Water absorption	0.64 percent	0.45 percent
4	Bulk density	1600 Kg/m³	1600 Kg/m³

SL. NO.	PROPERTY	STEEL BARS
1	Tensile strength, ultimate	500 MPa
2	Tensile strength, yield	250 MPa
3	Elongation at break	20%
4	Modulus of elasticity	200 GPa
5	Compressive yield strength	152 MPa
6	Bulk modulus	160 GPa
7	Poisson’s ratio	0.26
8	Shear modulus	79.3 GPa

SL. NO.	TYPES OF FIBRE	TENSILE STRENGTH (MPa)	MODULUS OF ELASTICITY (GPa)
1	Glass fibre	1050–3850	70
2	Basalt fibre	2800–3100	85–87

COLOUR	PALE YELLOW TO AMBER
Application temperature	15^°C–40^°C
Viscosity	Thixotropic
Density	1.25–1.28 g/cc
Pot life	2 hours @ 30^°C
Full cure	5 days @ 30^°C

PROPERTIES	GFRP	BFRP
PROPERTIES	UNIDIRECTIONAL	UNIDIRECTIONAL
Weight of fibre (g/m²)	920	330
Fibre thickness (mm)	0.90	0.6
Nominal thickness per layer (mm)	1.5	1.0
Fibre tensile strength (N/mm²)	3400	4840
Tensile modulus (N/mm²)	73000	86000

SPECIMEN DESCRIPTIONS	COMPRESSIVE STRENGTH (N/mm²)
Unconfined concrete cubes	39.12
Unidirectional GFRP confined concrete cubes with fibres perpendicular to loading	51.10
Unidirectional BFRP confined concrete cubes with fibres perpendicular to loading	56.26

SPECIMEN DESCRIPTIONS	COMPRESSIVE STRENGTH (N/mm²)
Unconfined concrete cylinders	32.94
Unidirectional GFRP confined concrete cylinders with fibres along the circumference	45.07
Unidirectional BFRP confined concrete cylinders with fibres along the circumference	49.51

SPECIMEN DESCRIPTIONS	FLEXURAL STRENGTH (N/mm²)
Unconfined concrete prisms	3.26
Unidirectional GFRP confined concrete prisms with fibres along the length	6.77
Unidirectional BFRP confined concrete prisms with fibres along the length	8.31

TYPE OF CONFINEMENT	ULTIMATE LOAD IN kN
Unconfined RC beam	105
Strengthened by basalt fibre mat in the ends of the RC beam	120.3
Strengthened by glass fibre mat in the ends of the RC beam	114.02

TYPE OF CONFINEMENT	ULTIMATE STRENGTH IN kN
Unconfined RC beam	91.25
Strengthened by basalt fibre mat in the ends of the RC beam	103.45
Strengthened by glass fibre mat in the ends of the RC beam	95.07

CYCLE NUMBER	PEAK LOAD	STIFFNESS	STIFFNESS DEGRADATION	ENERGY DISSIPATION	CUMULATIVE ENERGY DISSIPATION
	kN	kN/mm	kN/mm	kN-mm	kN-mm
1	10	35.71		0.12	0.12
2	20	35.71	0.00%	0.37	0.5
3	30	35.71	0.00%	1.16	1.66
4	40	35.36	1.82%	4.65	6.31
5	50	33.33	6.67%	16.06	22.37
6	60	30.76	13.85%	19.95	42.32
7	70	28.57	20.00%	43.48	85.81
8	80	26.66	25.33%	52	137.81
9	91.25	25.56	28.41%	126.21	264.01

CYCLE NUMBER	PEAK LOAD	STIFFNESS	STIFFNESS DEGRADATION	ENERGY DISSIPATION	CUMULATIVE ENERGY DISSIPATION
	kN	kN/mm	kN/mm	kN-mm	kN-mm
1	10	50		0.05	0.05
2	20	50	0.00%	0.42	0.47
3	30	50	0.00%	1.08	1.56
4	40	50	0.00%	2.65	4.21
5	50	49.51	0.99%	9.81	14.02
6	60	44.44	11.11%	18.15	32.17
7	70	37.23	25.53%	24.23	56.41
8	80	31.87	36.25%	50.8	107.21
9	90	27.86	44.27%	61.65	168.86
10	103.45	24.54	50.9%	114.72	283.58

CYCLE NUMBER	PEAK LOAD	STIFFNESS	STIFFNESS DEGRADATION	ENERGY DISSIPATION	CUMULATIVE ENERGY DISSIPATION
	kN	kN/mm	kN/mm	kN-mm	kN-mm
1	10	43.48		0.12	0.12
2	20	40	8.00%	0.75	0.87
3	30	40	8.00%	1.16	2.03
4	40	38.83	10.68%	2.25	4.28
5	50	32.05	26.28%	8.81	13.1
6	60	27.27	37.27%	23.02	36.13
7	70	25	42.50%	32.37	68.5
8	80	23.18	46.67%	50.3	118.8
9	90	21.95	49.51%	92.81	211.61
10	95.07	21.04	51.59%	125.67	337.28

[1] Corresponding Author: Rajamony Iyappan, e-mail: iyappan.vin@gmail.com, murugan@gcetly.ac.in

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Shear strengthening of reinforced concrete beams using fibre reinforced polymer composites

ABSTRACT