• Title/Summary/Keyword: 소성 힌지

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Assessment of Ductility and Plastic Hinge Region of Reinforced Concrete Multi-Column Bent (2주형 다주교각의 연성도 및 소성힌지 영역에 관한 연구)

  • Byun, Soon-Joo;Im, Jung-Soon
    • Journal of the Korean Society of Hazard Mitigation
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    • v.6 no.3 s.22
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    • pp.37-45
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    • 2006
  • In this study, displacement ductility capacity and plastic hinge regions of reinforced concrete multi-column bent with different transverse reinforcement ratio are investigated. The ductility increases remarkably as transverse reinforcement ratio increase and the multi-column bent loaded along transverse direction is more ductile. The plastic hinge length for special detailing requirements of transverse reinforcement is estimated. For high target ductility, plastic hinge length for confinement should be extended with increased transverse reinforcement ratio. The plastic hinge length of multi-column bent loaded along transverse direction is shorter than that along longitudinal direction, because of the different moment distribution.

Deformability of RC Beam-Column Assembles (철근콘크리트 보-기둥 접합부의 연성능력)

  • Lee, Jung-Yoon
    • Proceedings of the Korea Concrete Institute Conference
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    • 2008.04a
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    • pp.193-196
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    • 2008
  • This paper proposes a method to predict the ductility capacity of reinforced concrete beam-column joints failing in shear after the formations of plastic hinges at both ends of the adjacent beams. The current design code divides joints into two categories: Type 1 for structures in non seismically hazard area and Type 2 in seismically hazard area. While there are many researches related to joint shear strength in Type 1, those in regard to joint ductility capacity of Type 2 are scarce. This paper classified the ductility capacity of beam-column joints into column, joint panel, and beam deformability. Since a brittle failure such as shear or bond failure in the columns must be avoided, column deformability was calculated by elastic analysis. The plastic hinges of the adjacent beams affect joint deformability. Therefore, the prediction of joint deformability was calculated with consideration to the degradation of the diagonally compressed concrete due to the strain penetration.

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Plastic Hinge Modeling Based on Lumped Plasticity using a Generalized Finite Element Method (일반유한요소법을 이용한 집중소성힌지 모델링)

  • Son, Hong-Jun;Rhee, Seung-Ho;Kim, Dae-Jin
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.31 no.6
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    • pp.381-388
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    • 2018
  • This paper presents a generalized finite element formulation for plastic hinge modeling based on lumped plasticity in the classical Euler-Bernoulli beam elements. In this approach, the plastic hinges are effectively modeled using proper enrichment functions describing weak discontinuities of the solution. The proposed methodology enables the insertion of plastic hinges at an arbitrary location without modifying the connectivity of elements. The formations of plastic hinges are instead achieved by hierarchically adding degrees of freedom to existing elements. Convergence analyses such as h- and p-extensions are performed to investigate the effectiveness of the proposed method. The analysis results indicate that the proposed generalized finite element method can achieve theoretical convergence rates for both cases where plastic hinges are located at nodes and within an element, thus demonstrating its accuracy.

Evaluation of Plastic Rotational Capacity Based on Material Characteristics in Reinforced Concrete Flexural Members (재료 특성에 기반한 철근콘크리트 휨부재의 소성회전능력 산정)

  • Choi, Seung-Won;Kim, Woo
    • Journal of the Korea Concrete Institute
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    • v.22 no.6
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    • pp.825-832
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    • 2010
  • Although a critical section reaches its flexural strength in reinforced concrete structures, the structure does not always fail because moment redistribution occurs during the formation of plastic hinges. Inelastic deformation in a plastic hinge region results in plastic rotation. A plastic hinge mainly depends on material characteristics. In this study, a plastic hinge length and plastic rotation are evaluated using the flexural curvature distribution which is derived from the material models given in Eurocode 2. The influence on plastic capacity the limit values of the material model used, that is, ultimate strain of concrete and steel and hardening ratio of steel(k), are investigated. As results, it is appeared that a large ultimate strain of concrete and steel is resulting in large plastic capactiy and also as a hardening ratio of steel increases, the plastic rotation increases significantly. Therefore, a careful attention would be paid to determine the limit values of material characteristics in the RC structures.

Seismic Performance of PC Moment Frame with Plastic Shear Hinge (소성전단힌지를 갖는 PC 모멘트 골조의 내진성능)

  • Lim, Woo-Young;Hong, Sung-Gul
    • Journal of the Korea Concrete Institute
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    • v.27 no.4
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    • pp.353-362
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    • 2015
  • Cyclic loading tests for the PC moment frame with plastic shear hinges were performed to evaluate the seismic performance. The plastic shear hinges consisted of two steel plates were installed at the mid-length of the beam to connect the PC frames. Three shear links are existed in each steel plate. The three shear links were designed using shear force corresponding to the shear capacity of 50%, 75%, and 100% of the beam shear capacity. The proposed connections showed an efficient energy dissipation capacity and good structural performance. As a result, it is reasonable to design the plastic shear hinges using design shear capacity less than 100% of the beam shear capacity.

3-D Frame Design Using Second-Order Plastic-Hinge Analysis Accounting for Lateral Torsional Buckling (횡비틀림좌굴을 고려하는 2차 소성힌지해석을 이용한 3차원 강뼈대 구조물 설케)

  • 김승억;박주수
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.15 no.1
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    • pp.117-126
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    • 2002
  • In this paper, 3-D fame design using second-orders plastic-hinge analysis accounting for lateral torsional buckling is developed. This analysis accounts for material and geometric nonlinearities of the structural system and its component members. Moreover, the problem associated with conventional second-order plastic-hinge analyses, which do not consider the degradation of the flexural strength caused by lateral torsional buckling, is overcome. Efficient ways of assessing steel frame behavior including gradual yielding associated with residual stresses and flexure, second-order effect, and geometric imperfections are presented. In this study, a model consisting of the unbraced length and cross-section shape is used to account for lateral torsional buckling. The proposed analysis is verified by the comparison of the LRFD results. A case studs shows that lateral torsional buckling is a very crucial element to be considered in second-order plastic-hinge analysis. The proposed analysis is shown to be an efficient reliable tool ready to be implemented into design practice.

3-D Frame Analysis and Design Using Refined Plastic-Hinge Analysis Accounting for Local Buckling (국부좌굴을 고려하는 개선소성힌지해석을 이용한 3차원 강뼈대 구조물 해석 및 설계)

  • Kim, Seung Eock;Park, Joo Soo
    • Journal of Korean Society of Steel Construction
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    • v.14 no.1
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    • pp.13-21
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    • 2002
  • In this paper, 3-D frame design using refined plastic-hinge analysis accounting for local buckling is developed. This analysis accounts for material and geometric nonlinearities of the structural system and its component members. Moreover, the problem associated with conventional refined plastic-hinge analyses, which do not consider the degradation of the flexural strength caused by local buckling, is overcome. Efficient ways of assessing steel frame behavior including gradual yielding associated with residual stresses and flexure, second-order effect, and geometric imperfections are presented. In this study, a model consisting of the width-thickness ratio is used to account for local buckling. The proposed analysis is verified by the comparison of the LRFD results. A case study shows that local buckling is a very crucial element to be considered in second-order plastic-hinge analysis. The proposed analysis is shown to be an efficient, reliable tool ready to be implemented into design practice.

Material Nonlinear Analysis of RC Beams Based on Moment-Curvature Relations (모멘트-곡률 관계에 기초한 철근콘크리트 보의 재료비선형 해석)

  • 곽효경;김지은
    • Computational Structural Engineering
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    • v.11 no.4
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    • pp.295-307
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    • 1998
  • 철근콘크리트 보에 대해서 인장강화효과의 소성힌지길이를 고려한 재료비선형 해석을 수행하였다. 비선형 해석에서 자유도가 많은 대형구조물에 적용시키기에는 많은 제약이 따르는 복잡한 층상해석기법을 사용하는 대신 단면해석을 통해 미리 구성된 모멘트-곡률 관계를 이용하였으며, 유한요소해석에서 사용요소의 크기에 따른 수치해석상의 오차를 줄이기 위해 인장강화효과와 소성힌지길이 개념을 도입하였다. 마지막으로 제안된 해석 알고리즘의 타당성을 검증하기 위하여 해석결과와 실험결과간의 상호 관계를 비교, 분석하였다.

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Influence of ductility of reinforcement on the plastic hinge formation (철근의 연성이 소성힌지 생성에 미치는 영향)

  • Park, Dae-Gyun;Cho, Jae-Yeol;Park, Sung-Hyun
    • Proceedings of the Korea Concrete Institute Conference
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    • 2008.11a
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    • pp.97-100
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    • 2008
  • Subjected to seismic action causing large deformation of bridge columns, the plastic hinge region is commonly formed in the column end zone. The deformation capacity of a concrete column can be expressed by using plastic hinge length. The mechanical properties of high-strength reinforcing steel is different from that of normal-strength steel and the mechanical properties of steel will influence the plastic hinge formation. Therefore, in other to accurately predict the deformation of concrete column using high-strength steel, the plastic hinge length can be expressed as a function of the mechanical properties of steel such as the tensile to yield strength ratio and the strain at ultimate state. However, little research has been conducted into the effect of mechanical properties of steel on the plastic hinge length. It was difficult to measure the plastic hinge length from the test results. Therefore, the plastic hinge length of concrete columns was investigated from the curvature profile. A numerical approach was used to study the effect of various parameters on plastic hinge length. Based on the results of the numerical parametric study, a new expression for plastic hinge length was proposed.

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Discrete Optimum Design of Semi-rigid Steel Frames Using Refined Plastic Hinge Analysis and Genetic Algorithm (개선소성힌지해석과 유전자 알고리즘을 이용한 반강접 강골조의 이산최적설계)

  • Lee, Mal Suk;Yun, Young Mook;Kang, Moon Myoung
    • Journal of Korean Society of Steel Construction
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    • v.16 no.2 s.69
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    • pp.201-213
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    • 2004
  • A GA-based optimum design algorithm and a program for plane steel frame structures with semi-rigid connections are presented. The algorithm is incorporated with the refined plastic hinge analysis method wherein geometric nonlinearity is considered by using the stability functions of beam-column members, and material nonlinearity, by using the gradual stiffness degradation model that includes the effects of residual stresses, moment redistribution through the occurrence of plastic hinges, semi-rigid connections, and geometric imperfection of members. In the genetic algorithm, the tournament selection method and micro-GAs are employed. The fitness function for the genetic algorithm is expressed as an unconstrained function composed of objective and penalty functions. The objective and penalty functions are expressed as the weight of steel frames and the constraint functions, respectively. In particular, the constraint functions fulfill the requirements of load-carrying capacity, serviceability, ductility, and construction workability. To verify the appropriateness of the present method, the optimal design results of two plane steel frames with rigid and semi-rigid connections are compared.