Pilot Demonstration of a Strengthening Method for Steel-Bolted Connections Using Pre-Formable Carbon Fiber Cloth with VaRTM
Abstract
1. Introduction
1.1. Research Background
1.2. Strengthening Method Using CFRP by VaRTM
2. Experimental Methods
2.1. Seismic Resisting Steel Braces and Its Seismic Performance Evaluation
- (1) Ultimate shear strength of bolts:
- (2) Tensile strength of brace in net area:
- (3) Shear-out strength of brace or gusset plate:
- (4) Ultimate strength of gusset plate in net area:
2.2. Specimens
2.3. Specimen Preparation
3. Experimental Results
4. Conclusions
- We proposed a strengthening method using carbon fiber cloth for steel brace connections with steps and demonstrated that molding and bonding can be successfully conducted using VaRTM.
- The load-carrying capacity of the connection and the ductility factor of the steel brace were significantly improved using CFRP strengthening.
- The total elongation of the steel brace can be estimated using 3% plastic deformation of the length of bare steel position.
Supplementary Materials
Author Contributions
Funding
Institutional Review Board Statement
Informed Consent Statement
Data Availability Statement
Conflicts of Interest
References
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Failure Mode | Load-Carrying Capacity | Equation |
---|---|---|
Ultimate shear strength of bolts | 241 kN | (2) |
Tensile strength of brace in net area | 70.8 kN | (3) |
Shear-out strength of gusset plate | 144 kN | (4) |
Ultimate strength of gusset plate net area | 576 kN | (5) |
JBDPA requirement | 110 kN | (6) |
Specimen Name | Strengthening | Number of Specimens |
---|---|---|
NS | N/A | 1 |
CFS-full-1, -2 | Gross sectional strengthening model | 2 |
CFS-loss-1, -2 | Sectional loss strengthening model | 2 |
Material | Elastic Modulus | Yield Point | Tensile Strength |
---|---|---|---|
Steel (angle steel) | 200 GPa *1 | 370 Mpa *2 | 457 Mpa *2 |
UM46-40P [25] | 440 Gpa | - | 2400 Mpa |
BT70-20 [25] | 230 GPa | - | 2900 MPa |
Specimen Name | Maximum Load | Failure Mode |
---|---|---|
NS | 102 kN | Yielding and breaking at net area. |
CFS-full-1 | 125 kN | (1) Yielding in gross sectional area; (2) debonding of CFRP; (3) yielding at breakage in net area. |
CFS-full-2 | 127 kN | |
CFS-loss-1 | 126 kN | |
CFS-loss-2 | 127 kN |
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Matsui, T.; Suzuki, K.; Sato, S.; Kubokawa, Y.; Nakamoto, D.; Davaakhishig, S.; Matsumoto, Y. Pilot Demonstration of a Strengthening Method for Steel-Bolted Connections Using Pre-Formable Carbon Fiber Cloth with VaRTM. Materials 2021, 14, 2184. https://doi.org/10.3390/ma14092184
Matsui T, Suzuki K, Sato S, Kubokawa Y, Nakamoto D, Davaakhishig S, Matsumoto Y. Pilot Demonstration of a Strengthening Method for Steel-Bolted Connections Using Pre-Formable Carbon Fiber Cloth with VaRTM. Materials. 2021; 14(9):2184. https://doi.org/10.3390/ma14092184
Chicago/Turabian StyleMatsui, Takahiro, Kohei Suzuki, Sota Sato, Yuki Kubokawa, Daiki Nakamoto, Shijir Davaakhishig, and Yukihiro Matsumoto. 2021. "Pilot Demonstration of a Strengthening Method for Steel-Bolted Connections Using Pre-Formable Carbon Fiber Cloth with VaRTM" Materials 14, no. 9: 2184. https://doi.org/10.3390/ma14092184
APA StyleMatsui, T., Suzuki, K., Sato, S., Kubokawa, Y., Nakamoto, D., Davaakhishig, S., & Matsumoto, Y. (2021). Pilot Demonstration of a Strengthening Method for Steel-Bolted Connections Using Pre-Formable Carbon Fiber Cloth with VaRTM. Materials, 14(9), 2184. https://doi.org/10.3390/ma14092184