• Title/Summary/Keyword: Main reinforcement

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Improvement of Constructability of Coping by Reduction of Reinforcement Amount (철근량 저감을 통한 코핑부 시공성 향상)

  • Park, Bong-Sik;Park, Sung-Hyun;Cho, Jae-Yeol
    • Proceedings of the KSR Conference
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    • 2011.10a
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    • pp.1577-1582
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    • 2011
  • Recently rapid construction of bridge is a main interest in construction. A research on rapid construction of pier coping is urgently needed because pier, which is a bridge understructure, directly affect lane reduction and increase of social cost. Precast assembly method and pre-assembly method are the main subjects of rapid construction. But these researches have focused not on reduction of reinforcement amount, but on modifying production method of coping. Reinforcement amount of design specification is as much as that of coping under constructing. So different approach is needed for reduction of reinforcement amount. In this paper, design of pier coping using strut-tie model was proposed for reduction of reinforcement amount and improvement of constructability. Railway bridge pier coping under constructing was analyzed using a finite element method and designed using strut-tie model.

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An Effective Adaptive Dialogue Strategy Using Reinforcement Loaming (강화 학습법을 이용한 효과적인 적응형 대화 전략)

  • Kim, Won-Il;Ko, Young-Joong;Seo, Jung-Yun
    • Journal of KIISE:Software and Applications
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    • v.35 no.1
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    • pp.33-40
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    • 2008
  • In this paper, we propose a method to enhance adaptability in a dialogue system using the reinforcement learning that reduces response errors by trials and error-search similar to a human dialogue process. The adaptive dialogue strategy means that the dialogue system improves users' satisfaction and dialogue efficiency by loaming users' dialogue styles. To apply the reinforcement learning to the dialogue system, we use a main-dialogue span and sub-dialogue spans as the mathematic application units, and evaluate system usability by using features; success or failure, completion time, and error rate in sub-dialogue and the satisfaction in main-dialogue. In addition, we classify users' groups into beginners and experts to increase users' convenience in training steps. Then, we apply reinforcement learning policies according to users' groups. In the experiments, we evaluated the performance of the proposed method on the individual reinforcement learning policy and group's reinforcement learning policy.

A Characteristic Study on Shear Strength of Reinforced Concrete Beams according to Longitudinal Reinforcement Ratio and Size Effect (철근콘크리트보의 인장철근비와 크기효과에 의한 전단강도 특성 연구)

  • Yu, In-Geun;Noh, Hyung-Jin;Lee, Ho-Kyung;Baek, Seung-Min;Kim, Woo-Suk;Kwak, Yoon-Keun
    • Journal of the Architectural Institute of Korea Structure & Construction
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    • v.36 no.2
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    • pp.117-126
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    • 2020
  • The main objective of this experimental study is to investigate shear strength of reinforced concrete beams according to longitudinal reinforcement ratio (ρ) and size effect. In order to find out the shear strength according to the tensile reinforcement ratio, in particular, the main variables are 100%, 75% and 50% of ρ=0.01 which is widely used in construction field. A total of twelve RC beams were tested under 4-point loading conditions. In addition to the existing proposal equations, the theoretical values such as KBC and ACI equations are compared with the experimental data. Through this analysis, this study is designed to provide more reasonable equations for shear design of reinforced concrete beams. When shear reinforcement bar spacing of nine specimens (R*-1, R*-2, and R*-3 series) fixed as d/s=2.0 and three specimens of R*-4 series fixed as d/s=1.5 are compared, the shear strength of two groups showed similar values. As a result, the current standard of d/s=2.0 for shear reinforcement bar spacing may be somewhat alleviated.

Effects of details of lattice reinforcement for punching shear strength of slab-column connections (슬래브-기둥 접합부의 뚫림 전단강도에 대한 래티스 보강상세의 영향)

  • Kim, You-Ni;Park, Hong-Gun
    • Proceedings of the Korea Concrete Institute Conference
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    • 2006.11a
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    • pp.17-20
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    • 2006
  • A flat plate-column connection is susceptible to brittle punching shear failure, which may result in the necessity of shear reinforcement. In previous, experimental tests were performed to study the capacity of slab-column connections strengthened with various shear reinforcement, and the capacity of the specimens with lattice reinforcement are superior to the others. In present study, to study for effects of details of lattice reinforcement, experimental studies was performed. Main parameters are the amount of lattice shear reinforcement, arrangement of lattice and the effect of flexural re-bar. And capacity of the specimen with small amount of lattice reinforcement was higher than the capacity of other shear reinforcement.

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Evaluation of Damage Indices for RC Bridge Piers with Premature Termination of Main Reinforcement Using Inelastic FE Analysis (비탄성 유한요소해석을 이용한 주철근 단락을 갖는 철근콘크리트 교각의 손상지수 평가)

  • 김태훈;신현목
    • Journal of the Earthquake Engineering Society of Korea
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    • v.5 no.4
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    • pp.39-49
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    • 2001
  • In this paper, inelastic analysis procedures are presented for the seismic performance evaluation of RC bridge piers with premature termination of main reinforcement. The mechanical characteristic of cracked concrete and reinforcing bar in concrete has been modeled, considering the bond effect between reinforcing bars and concrete, the effect of aggregate interlocking at crack surface and the stiffness degradation after the crack. The smeared crack approach is incorporated. In boundary plane at which each member with different thickness is connected, local discontinuous deformation due to the abrupt change in their stiffness can be taken into account by introducing interface element. The increase of concrete strength due to the lateral confining reinforcement has been also taken into account to model the confined concrete. The proposed numerical method for seismic performance evaluation of RC bridge piers with premature termination of main reinforcement will be verified by comparison with reliable experimental results.

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Stress-Strain Relationships of Concrete Confined by Spiral Reinforcement (나선근으로 횡보강된 콘크리트의 응력-변형도 관계)

  • 김진근;박찬규
    • Proceedings of the Korea Concrete Institute Conference
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    • 1993.04a
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    • pp.119-123
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    • 1993
  • Axial load-strain relationships of confined concrete with spiral reinforcement were investigated. The main variables were compressive strength of concrete, spacing of hoop reinforcement, and specimen height of plain concrete. The program included tests of eleven confined specimens, and twelve plain specimens, but for all specimens no longitudinal reinforcement was provided. Load-strain curves of confined and plain concrete specimens are reporeted.

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Characteristic Behavior of High-Strength Concrete Columns under Simulated Seismic Loading

  • Hwang, Sun-Kyoung
    • International Journal of Concrete Structures and Materials
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    • v.18 no.2E
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    • pp.79-87
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    • 2006
  • The main objective of this research is to examine the behavior of high-strength concrete(HSC) columns. Eight test columns in one-third scale were tested under the conditions of cyclic lateral force and a constant axial load equal to 30% of the column axial load capacity. The $200{\times}200mm$ square columns were reinforced with eight DB bars constituting a longitudinal steel ratio of 2.54% of the column cross-sectional area. The main experimental parameters were volumetric ratio of transverse reinforcement(${\rho}_s$=1.58, 2.25 percent), tie configuration(Type H, Type C, Type D) and tie yield strength($f_{yh}$=548.8 and 779.1 MPa). It was found that the hysteretic behaviour and ultimate deformability of HSC columns were influenced by the amount and details of transverse reinforcement in the potential plastic hinge regions. Columns of transverse reinforcement in the amount 42 percent higher than that required by seismic provisions of ACI 318-02 showed ductile behavior. At 30% of the axial load capacity, it is recommended that the yield strength of transverse reinforcement be held equal to or below 548.8 MPa. Correlations between the calculated damage index and the damage progress are proposed.

Development of a Composite Fiber Reinforcement Pavement using Eco-Friendly Grid and Dispersive Fibers (친환경 쉬트형 보강재 및 분산성 섬유를 적용한 복합 섬유 보강 포장 개발)

  • Park, Ju Won;Kim, Hyeong Su;Kim, Hyeok Jung;Kim, Sung Bo
    • International Journal of Highway Engineering
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    • v.19 no.6
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    • pp.57-66
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    • 2017
  • PURPOSES : This study develops eco-friendly asphalt reinforcement materials applicable to bridge deck pavement. The main purpose is to ensure highly reliable quality applicable to structures and the possibility of practical application. The main target of the study is to develop materials that are environmentally friendly and capable of improving performance. METHODS : The application of double-reinforcement fiber improves the performance of the road pavement. 1. We use recycled film for application of sheet-typed reinforcement. 2. We use preprocessing fibers to reinforce the properties of composite pavement materials. RESULTS : The developed products may produce materials that fit the purpose of achieving stability and environmental friendliness. Sheet-typed reinforcements use more than 50% recycled resin. The most important type of damage to the asphalt layer is deflection (plastic deformation). These products have a very high deflection resistance of not less than 6,000 cycles/mm. In addition, all performance is excellent. Thus, it will be easier to access the field in the future. CONCLUSIONS : Fiber-reinforced asphalt pavement showed excellent performance. Sheet-typed reinforcements containing 50% recycling resin produced good performance in terms of functionality as well as environmental friendliness. Thus, enhancing the field applicability will enhance the usability of the reinforcements.

The Relationships Between Shear Reinforcement Ratios and Shear Strength in Reinforced Concrete Deep Beams (철근콘크리트 깊은 보에서 전단철근비와 전단내력의 관계)

  • Yang Keun-Hyeok;Park Jeong-Hwa;Chung Heon-Soo
    • Proceedings of the Korea Concrete Institute Conference
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    • 2004.05a
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    • pp.256-259
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    • 2004
  • The objective of this experimental study is to understand the effects of horizontal and vertical shear reinforcement on the shear strength of concrete deep beams. Main variables were the horizontal shear reinforcement ratio $(P_{sh})$, vertical shear reinforcement ratio$(P_{sv})$ and shear span-to-overall depth ratio(a/h). Test results revealed that the effectiveness of shear resistance of shear reinforcement was greatly related to the a/h. For the beams with $a/h\geq1.0$, the vertical shear reinforcement was more effective than horizontal shear reinforcement.

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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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