The Tension-Stiffening Contribution of NSM CFRP to the Behavior of Strengthened RC Beams
Abstract
:1. Introduction
2. Segmental Moment-Rotation Approach
2.1. Partial-Interaction Tension Stiffening Analysis
2.2. Size-Dependent Stress-Strain of Concrete
2.3. Hinge Analysis
3. Experimental Program
Specimen name & details | Bonded length (mm) | Beam length (mm) | Shape of NSM CFRP reinforcement | Number of NSM FRP reinforcements |
---|---|---|---|---|
CB (Control beam) | - | 2000 | - | - |
A1 (Strengthened beam) | 1800 | 2000 | bar | 1 |
A2 (Strengthened beam) | 1900 | 2000 | bar | 1 |
Jung-1 [22] | 2700 | 3000 | bar | 1 |
Capozucca-1 [23] | 1300 | 1500 | bar | 2 |
Teng-1 [24] | 1800 | 3000 | strip | 1 |
Teng-2 [24] | 2900 | 3000 | strip | 1 |
Materials and Samples
Material | Compressive strength (MPa) | Flexure strength (MPa) | Yield stress (MPa) | Ultimate strength (MPa) | Elastic modulus (GPa) | Strain at failure (%) |
---|---|---|---|---|---|---|
Concrete | 43.24 (cube) 35.63 (Cylinder) | 5.01 | - | - | 30.1 | - |
Steel- Φ 12 mm | - | - | 520 | 587 | 200 | 20 |
Steel- Φ 10 mm | - | - | 529 | 578 | 200 | 21 |
Steel- Φ 8 mm | - | - | 380 | 450 | 200 | 29 |
CFRP- Φ 12 mm | - | - | - | 2400 | 165 | - |
Temperature | 15 °C | 35 °C |
---|---|---|
Compressive strength | 70–80 MPa | 85–95 MPa |
Tensile strength | 14–17 MPa | 16–19 MPa |
Shear strength | 24–27 MPa | 26–31 MPa |
4. Results and discussion
4.1. Experimental Results
Specimen name | Pcr (kN) | Py (kN) | Δy (mm) | Pu (kN) | Δu (mm) | Failure mode |
---|---|---|---|---|---|---|
CB | 10.6 | 61.0 | 7.7 | 64.4 | 24.7 | Flexure failure (Concrete crushing after steel yielding) |
A1 | 14.0 | 110.6 | 13.0 | 130.8 | 18.6 | Debonding (Concrete cover separation) |
A2 | 15.0 | 104.5 | 10.7 | 133.2 | 19.2 | Debonding (Concrete cover separation) |
4.2. Validation of Segmental Moment-Rotation Approach
5. Conclusions
Acknowledgments
Author Contributions
Conflicts of Interest
References
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Shukri, A.A.; Darain, K.M.u.; Jumaat, M.Z. The Tension-Stiffening Contribution of NSM CFRP to the Behavior of Strengthened RC Beams. Materials 2015, 8, 4131-4146. https://doi.org/10.3390/ma8074131
Shukri AA, Darain KMu, Jumaat MZ. The Tension-Stiffening Contribution of NSM CFRP to the Behavior of Strengthened RC Beams. Materials. 2015; 8(7):4131-4146. https://doi.org/10.3390/ma8074131
Chicago/Turabian StyleShukri, Ahmad Azim, Kh Mahfuz ud Darain, and Mohd Zamin Jumaat. 2015. "The Tension-Stiffening Contribution of NSM CFRP to the Behavior of Strengthened RC Beams" Materials 8, no. 7: 4131-4146. https://doi.org/10.3390/ma8074131