Flexural Behavior of Hybrid-Reinforced Concrete Exterior Beam-Column Joints under Static and Cyclic Loads
Abstract
:1. Introduction
2. Test Program
2.1. Description of Specimens
2.2. Material Properties
2.3. Test Setup
2.4. Test Procedure
3. Results and Discussion
3.1. Cracking and Ultimate Loads and Failure Modes
3.1.1. Group I (BCJs with Hybrid Concrete)
3.1.2. Group II (BCJs with Hybrid Reinforcement)
3.1.3. Group III (BCJs under Cyclic Loading)
3.2. Ductility
3.3. Absorption of Energy
4. Conclusions
- For the beam-column joint specimens that adopted the concrete hybridization technique (by RPC at different areas) under static loading condition, the ultimate and the first cracking loads increased about 8–32% and 20–60% compared with the homogenous NC joint, respectively.
- Using CFRP bars as internal hybridization system (33% of main reinforcement) has no effect on the first cracking load but ultimate load increased about 11%. On the other side, using NSM-CFRP bars as external hybridization system (33% of main reinforcement) exhibited an increase in first cracking and ultimate loads of about 30% and 8%, respectively.
- For beam-column joints with hybrid concrete or hybrid reinforcement as main reinforcement under cyclic loading, the ultimate load capacity increased about 39% and decreased about 15% with respect to the reference joint, respectively.
- The beam-column joints with hybrid concrete under static loading exhibited an increase in the ductility between 6–14% compared with the homogenous NC beam-column joint. For hybrid internal reinforcement joint (33% CFRP as main reinforcement), it showed an increase in the ductility of about 36% because of the effectiveness of this technique in improvement of the ductility, while the joint with hybrid external reinforcement by NSM technique showed a low increase of about 5% because of debonding of CFRP bars.
- The cumulative ductility values increased about 12% for joint with hybrid concrete, while it decreased about 40% for the joint with internal hybrid reinforcement because of brittle behavior of the CFRP bars.
- The specimens with hybrid concrete technique had more energy dissipation capacity than those that adopted the hybrid reinforcement technique.
Author Contributions
Funding
Conflicts of Interest
References
- ACI Committee. 352R-02: Recommendations for the Design of Beam-Column Connections in Monolithic Reinforced Concrete Structures. In Proceedings of the ACI Manual of Concrete Practice: Part 3; ACI Committee: Detroit, MI, USA, 2002. [Google Scholar]
- Uma, S.R.; Sudhir, K.J. Seismic Behaviour of Beam-Column Joints in Reinforced Concrete Moment Resisting Frames—Review of codes. J. Struct. Eng. Mech. 2006, 23, 579–597. [Google Scholar] [CrossRef]
- Rajaram, P.; Murugesan, A.; Thirugnanam, G.S. Experimental Study on Behaviour of Interior Reinforced Concrete Beam-Column Joints Subjected to Cyclic Loading. Int. J. Appl. Eng. Res. 2010, 1, 49–59. [Google Scholar]
- Leung, H.Y.; Balendran, R.V. Flexural Behaviour of Concrete Beams Internally Reinforced with Steel Rebars and GFRP Rods. J. Struct. Survey 2003, 21, 146–157. [Google Scholar] [CrossRef]
- Raj, J.; Jeen, G. Flexural Behavior of UHPC–RC Composite Beams. Proceedings of International Conference on Technological Trends (ICTT), Trivandrum, India; 2010; p. 5. [Google Scholar]
- Mahdi, A.M. Experimental and Theoretical Analysis for Behavior of Concrete Corbels with Hybrid Reinforcement. Master’s Thesis, Babylon University, Babylon, Iraq, 2015. [Google Scholar]
- ACI-Committee 318. Building Code Requirements for Structural Concrete; ACI-318M-14 and Commentary; Institute of American Concrete: Detroit, MI, USA, 2014. [Google Scholar]
- Standard Specification of Steel Fibers for Fiber-Reinforced Concrete (ASTM A820-11); American Society for Testing and Materials: West Conshohocken, PA, USA, 2011.
- Hughes Brothers Inc. Carbon Fiber Reinforced Polymer (CFRP) Rebar Aslan 200/201; Technical Data Sheet; Hughes Brothers Inc.: Seward, NE, USA, 2010. [Google Scholar]
- Hussain, M.; Alfarabi, S.; Basunbul, A.; Baluch, M.H.; Al-Sulaimani, G.J. Flexural Behavior of Precracked Reinforced Concrete Beams Strengthened Externally by Steel Plates. ACI Struct. J. 1995, 92, 114–121. [Google Scholar]
- Maha, G.Z. Structural Behavior of Hybrid Reinforced Concrete Beam-Column Joints. Doctoral Thesis, Babylon University, Babylon, Iraq, 2019. [Google Scholar]
- Muthuswamy, K.R.; Thirugnanam, G.S. Structural Behaviour of Hybrid Fibre Reinforced Concrete Exterior Beam Column Joint Subjected to Cyclic Loading. Int. J. Civ. Struct. Eng. 2014, 4, 262–273. [Google Scholar]
Groups | BCJ Designation | Type of Hybridization | Type of Loading |
---|---|---|---|
Group(I) BCJs with Hybrid Concrete | BCJ1.F.N.S | Ref. (homogenous NC) | Static Loading |
BCJ2.F.HC1.S | HC1 | ||
BCJ3.F.HC2.S | HC2 | ||
BCJ4.F.HC3.S | HC3 | ||
Group(II) BCJs with Hybrid Reinforcement | BCJ5.F.HR1.S | HR1 (0.67 As + 0.33Acf internally) | Static Loading |
BCJ6.F.HR2.S | HR2(0.67As + 0.33 Acf externally) | ||
Group(III) BCJs with Hybrid Concrete or Hybrid Reinforcement | BCJ7.F.N.C | Ref. (homogenous NC) | Cyclic Loading |
BCJ8.F.HC2.C | HC2 | ||
BCJ9.F.HR1.C | HR1 (0.67 As + 0.33Acf internally) |
Specimens | Beam | Column |
---|---|---|
BCJs with Homogenous Reinforcement BCJ1.F.N.S BCJ2.F.HC1.S BCJ3.F.HC2.S BCJ4.F.HC3.S BCJ7.F.N.C BCJ8.F.HC2.C |
|
|
BCJs with Hybrid Reinforcement BCJ5.F.HR1.S BCJ6.F.HR2.S BCJ9.F.HR1.C |
|
|
Parameter | Type of Concrete | |
---|---|---|
NC | RPC | |
Cement (kg/m3) | 400 | 1000 |
Micro silica fume (kg/m3) | ---- | 245 |
Fine aggregate (kg/m3) | 780 | 1000 |
Coarse aggregate (kg/m3) | 896 | ---- |
w/cementitious ratio | 0.47 | 0.17 |
Steel Fiber volume fraction Vf (%) | ---- | 1 |
Super plasticizer % by weight of cementitious material | 1 | 6 |
Groups | BCJ Designation | Cracking Load Pcr (kN) | * | Ultimate Load Pu (kN) | * | ||
---|---|---|---|---|---|---|---|
Flexure Crack | Shear Crack | Flexure Crack | Shear Crack | ||||
I | BCJ1.F.N.S | 10 | 40 | -- | -- | 74 | -- |
BCJ2.F.HC1.S | 12 | 45 | 20 | 13 | 80 | 8 | |
BCJ3.F.HC2.S | 15 | 50 | 50 | 25 | 89 | 20 | |
BCJ4.F.HC3.S | 16 | 50 | 60 | 25 | 98 | 32 | |
II | BCJ5.F.HR1.S | 10 | 45 | 0 | 13 | 82 | 11 |
BCJ6.F.HR2.S | 13 | 42 | 30 | 5 | 80 | 8 | |
III | BCJ7.F.N.C | 10 cyc.1 | 35 cyc.6 | -- (0) | -- (−13) | 59 cyc.11 | -- (−20) |
BCJ8.F.HC2.C | 15 cyc.1 | 45 cyc.6 | 50 (0) | 29(−10) | 82 cyc.11 | 39 (−8) | |
BCJ9.F.HR1.C | 10 cyc.1 | 35 cyc.4 | 0(0) | 0 (−22) | 50 cyc.7 | −15 (−39) |
BCJ Designation | (mm) * | (mm) | Ductility Factor, | |
---|---|---|---|---|
BCJ1.F.N.S | 11.65 | 25.64 | 2.20 | ------- |
BCJ2.F.HC1.S | 12.58 | 29.4 | 2.34 | 6 |
BCJ3.F.HC2.S | 13.4 | 33.64 | 2.51 | 14 |
BCJ4.F.HC3.S | 11.85 | 28.43 | 2.40 | 9 |
BCJ5.F.HR1.S | 12.76 | 38.22 | 3.0 | 36 |
BCJ6.F.HR2.S | 14.2 | 32.68 | 2.30 | 5 |
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Ali, A.Y.; Al-Rammahi, A.A. Flexural Behavior of Hybrid-Reinforced Concrete Exterior Beam-Column Joints under Static and Cyclic Loads. Fibers 2019, 7, 94. https://doi.org/10.3390/fib7100094
Ali AY, Al-Rammahi AA. Flexural Behavior of Hybrid-Reinforced Concrete Exterior Beam-Column Joints under Static and Cyclic Loads. Fibers. 2019; 7(10):94. https://doi.org/10.3390/fib7100094
Chicago/Turabian StyleAli, Ammar Yaser, and Ali Abdulameer Al-Rammahi. 2019. "Flexural Behavior of Hybrid-Reinforced Concrete Exterior Beam-Column Joints under Static and Cyclic Loads" Fibers 7, no. 10: 94. https://doi.org/10.3390/fib7100094
APA StyleAli, A. Y., & Al-Rammahi, A. A. (2019). Flexural Behavior of Hybrid-Reinforced Concrete Exterior Beam-Column Joints under Static and Cyclic Loads. Fibers, 7(10), 94. https://doi.org/10.3390/fib7100094