• Title/Summary/Keyword: Reinforcement ratio

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Structural Performance of Reinforcement corrosion RC Beams Strengthened with Epoxy Mortar System (에폭시모르타르로 보강된 부식철근 RC보의 구조적 성능)

  • Han, Bok-Kyu;Hong, Geon-Ho;Shin, Yeong-Soo;Chung, Lan
    • Proceedings of the Korea Concrete Institute Conference
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    • 2000.04a
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    • pp.769-774
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    • 2000
  • The purpose of this study was to investigate the structural performance of reinforcement corrosion reinforced concrete beams strengthened with epoxy mortar system. Main test parameters are existence and the magnitude of the reinforcement corrosion and the reinforcing bar and the tensile reinforcement ratio of the specimens. eight beam specimens were tested to investigate the effectiveness of each test variables on maximum load capacity and failure mode. Test results showed that the ultimate moment of th specimens were higher tan the nominal moment and the flexural stiffness was increased about 2.5 times and the cracking moments occurred over 60% of the failure moment in comparison with same sized control beam. However, note that epoxy mortar may conduct member into brittle failure mode.

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Load-Displacement Formulations of Low-rise Unbounded RC Shear Walls with or without Openings

  • Lou, K. Y.;Cheng, F. Y.;Sheu, M. S.;Zhang, X. Z.
    • Computational Structural Engineering : An International Journal
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    • v.1 no.2
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    • pp.117-130
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    • 2001
  • Investigations of low-rice unbounded reinforced concrete shear walls with or without openings are performed with comparison of analytical and experimental results. Theoretical analysis is based on nonlinear finite element algorithm, which incorporates concrete failure criterion and nonlinear constitutive relationships. Studios focus on the effects of height-to-length ratio of shear walls, opening ratio, horizontal and vertical reinforcement radios, and diagonal reinforcement. Analytical solutions conform well with experimental results. Equations for cracking, yielding and ultimate loads with corresponding lateral displacements are derived by regression using analytical results and experimental data. Also, failure modes of low-rise unbounded shear walls are theoretically investigated. An explanation of change in failure mode is ascertained by comparing analytical results and ACI code equations. Shear-flexural failure can be obtained with additional flexural reinforcement to increase a wall's capacity. This concept leads to a design method of reducing flexural reinforcement in low-rise bounded solid shear wall's. Avoidance of shear failure as well as less reinforcement congestion leer these walls is expected.

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Numerical model for local corrosion of steel reinforcement in reinforced concrete structure

  • Chen, Xuandong;Zhang, Qing;Chen, Ping;Liang, Qiuqun
    • Computers and Concrete
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    • v.27 no.4
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    • pp.385-393
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    • 2021
  • Reinforcement corrosion is the main cause of the durability failure of reinforced concrete (RC) structure. In this paper, a three-dimensional (3D) numerical model of macro-cell corrosion is established to reveal the corrosion mechanisms of steel reinforcement in RC structure. Modified Direct Iteration Method (MDIM) is employed to solve the system of partial differential equations for reinforcement corrosion. Through the sensitivity analysis of electrochemical parameters, it is found that the average corrosion current density is more sensitive to the change of cathodic Tafel slope and anodic equilibrium potential, compared with the other electrochemical parameters. Furthermore, both the anode-to-cathode (A/C) ratio and the anodic length have significant influences on the average corrosion current density, especially when A/C ratio is less than 0.5 and anodic length is less than 35 mm. More importantly, it is demonstrated that the corrosion rate of semi-circumferential corrosion is much larger than that of circumferential corrosion for the same A/C ratio value. The simulation results can give a unique insight into understanding the detailed electrochemical corrosion processes of steel reinforcement in RC structure for application in service life prediction of RC structures in actual civil engineer.

Seismic Behavior of Slender Coupling Beams Constructed with High-Performance Fiber Reinforced Cementitious Composite (고성능 섬유 보강 시멘트 복합체(HPFRCC)를 적용한 세장한 연결보의 내진거동 평가)

  • Han, Sang Whan;Kwon, Hyun Wook;Shin, Myung Su;Lee, Ki Hak;Cho, Young Wook
    • Journal of the Earthquake Engineering Society of Korea
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    • v.17 no.6
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    • pp.271-278
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    • 2013
  • The hysteretic behavior of diagonal reinforced coupling beams is excellent during earthquakes. However, construction of the diagonal reinforced coupling beams is difficult due to complex reinforcement details required by current code procedures (ACI 318-11). Due to the detail requirement, reinforcement congestion and interference among transverse reinforcement always occur during construction field. When the aspect ratio of the beam is large, the interference of reinforcement becomes more serious. The objective of this paper is to simplify the reinforcement details of slender coupling beams by reducing transverse reinforcement around the beam perimeter. For this purpose, high- performance fiber reinforced cementitious composites are used for making coupling beams. Experiments were conducted using three specimens having aspect ratio 3.5. Test results showed that HPFRCC coupling beams with half the transverse reinforcement required by ACI 318-11 provided identical seismic capacities to the corresponding coupling beams having requirement satisfying the requirement specified in ACI 318-11.

Characteristics of Flexuarl-Shear Behavior of Beam Using Demonstrated CFRP Rod (국내 시범 생산 CFRP rod를 적용한 보 부재의 휨-전단 특성)

  • Choi, So-Yoeng;Kim, Il-Sun;Choi, Myoung-Sung;Yang, Eun-Ik
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.26 no.5
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    • pp.86-94
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    • 2022
  • Replacement of FRP rod as steel reinforcement has been attracted significantly to prevent the degradation of the concrete structure due to corrosion. So, the technology development to extend the structure's service life by improving FRP properties has been proceeded worldwide. Accordingly, it is necessary to develop Korea's CFRP rod and CFRP grid, including the manufacturing techniques to improve the properties of high-strength and high-stiffness. Moreover, the research should be conducted to evaluate the structural behavior of the beams using the CFRP rod or grid. This study investigates the flexural and shear behavior of reinforced concrete beam using demonstrated CFRP rod as reinforcement according to the reinforcement ratio and shear span to depth ratio. From the results, when the reinforcement ratio is out of a specific range, it is seemed that the effect on performance improvement of the beam using CFRP rod is cancelled or not significant. Meanwhile, when the CFRP rod was used as reinforcement, the possibility of shear failure occurred, even steel stirrups were installed in the beam with CFRP rod as tensile reinforcement according to the Korean Design Standard. Therefore, when the CFRP rod is used as tensile reinforcement in a beam, it should be prepared that a specific limitation of reinforcement ratio and an investigation against shear failure. Also, the ductility of the beam using the CFRP rod is determined by the deformation energy evaluation method. So, the ductility should be investigated by applying the deformation energy evaluation method that reflects the structural behavior of the beam.

Flexural behavior of titanium bar reinforced granite with various reinforcement ratio

  • Lim, Woo-Young
    • Structural Engineering and Mechanics
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    • v.74 no.6
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    • pp.757-769
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    • 2020
  • Granite is commonly used in the construction of the ancient stone pagodas of Korea. The material has excellent weathering resistance and durability, as well as high compressive strength. Most of the stone-made state-designated architectural heritage of Korea is made of granite. Therefore, the understanding of the structural feasibility of stone-made architectural heritage is crucial. Even though, until now, experimental studies for the reinforced stone have been rarely performed. This study intends to suggest a new methodology for the reinforcement of granite using a threaded titanium bar. Through the experimental study, the flexural behavior of the reinforced granite depending on the reinforcement ratio is investigated. Based on the test results, a moment-displacement relationship for the design of reinforced granite is suggested.

Seismic performance of RC short columns with light transverse reinforcement

  • Tran, Cao Thanh Ngoc;Li, Bing
    • Structural Engineering and Mechanics
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    • v.67 no.1
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    • pp.93-104
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    • 2018
  • The seismic behavior of reinforced concrete (RC) short columns with limited transverse reinforcement is investigated in this paper through an experimental program. The experimental program consists of four small-scale RC columns with an aspect ratio of 1.7, which are tested to the axial failure stage. The cracking patterns, hysteretic responses, strains in reinforcing bars, displacement decomposition and cumulative energy dissipation of the tested specimens are reported in detail in the paper. The effects of column axial load are investigated to determine how this variable might influence the performance of the short columns with limited transverse reinforcement. Brittle shear failure was observed in all tested specimens. Beneficial and detrimental effects on the shear strength and drift ratio at axial failure of the test specimens due to the column axial load are found in the experimental program, respectively.

Stress-Strain Behavior of Confined Concrete Columns according to Transverse Reinforcement Volumetric Ratio (횡방향 구속철근비에 따른 교각요소부재의 응력-변형 거동)

  • Oh Byung Hwan;Kim Ki Wan;Chioi Seung Won;Lee Jae Hoon
    • Proceedings of the Korea Concrete Institute Conference
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    • 2004.11a
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    • pp.37-40
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    • 2004
  • An experimental study was conducted to investigate the stress-strain behavior of confined concrete columns according to transverse reinforcement volumetric ratio. Uniaxial loading tests of eleven column specimens$(250\times100\times500mm)$ with rectangular section were conducted to study effect of confinement. The main variables in this test are transverse reinforcement volumetric ratio and cross tie arrangement. the results indicate that the strength and the ductility of confined concrete columns are subjected to transverse reinforcement volumetric ration and cross tie arrangement.

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Effect of Steel Reinforcement Ratio on the Flexural Behavior of RC Beams Strengthened with CFRP Sheets (탄소섬유쉬트로 보강된 RC부재의 철근량에 따른 휨 보강성능)

  • You, Young-Chan;Choi, Ki-Sun;Kim, Keung-Hwan
    • Proceedings of the Korea Concrete Institute Conference
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    • 2006.11a
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    • pp.177-180
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    • 2006
  • Experimental study has been performed in order to evaluate the effects of steel reinforcement ratio on the flexural behavior of RC beams strengthened with CFRP sheets. The steel reinforcement ratio of $0.78%({\rho}_s/{\rho}_b=24%)$ is selected to have balance failure when control RC beams were strengthened with 1 ply CFRP sheet. Total 6 half-scale specimens were manufactured including each unstrengthened specimens, which have 3 different reinforcement ratios. The specimens strengthened with CFRP sheet consist of under- or over-reinforced beams for the balanced failure condition. Moreover, the behavior of un strengthened or strengthened beams were compared to evaluate flexural performance. The results of this study show that the over-reinforced specimens were failed by concrete crushing prior to CFRP sheet failure by debonding or rupture. On the contrary, the under-reinforced specimen were failed by rupture of CFRP sheet.

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Evaluation of Bamboo Reinforcements in Structural Concrete Member

  • Siddika, Ayesha;Al Mamun, Md. Abdullah;Siddique, Md. Abu Bakar
    • Journal of Construction Engineering and Project Management
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    • v.7 no.4
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    • pp.13-19
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    • 2017
  • This study is based on the use and performance of bamboo reinforcements in construction of low-cost structures. This study investigated the physical and mechanical properties of bamboo reinforcements. Bamboo reinforced concrete beam specimens were tested with different reinforcement ratios and observed the load capacity, deflection and failure patterns. It was observed that, flexural strength of bamboo reinforced column is sufficient higher than plain cement concrete and comparable to steel reinforced concrete beams. Bamboo reinforced concrete columns with different reinforcement ratio also tested and observed the ultimate compressive strength and failure pattern. It found, all columns failed in a similar pattern due to crushing of concrete. According to cost analysis, bamboo reinforced beams and columns with moderate reinforcement ratio showed the best strength-cost ratio among plain cement concrete and steel reinforced concrete.