• Title, Summary, Keyword: yield line theory

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Load capacity of high-strength reinforced concrete slabs by yield line theory

  • Gorkem, Selcuk Emre;Husem, Metin
    • Computers and Concrete
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    • v.12 no.6
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    • pp.819-829
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    • 2013
  • The objective of this study is to determine whether or not the yield line theory, an effective method widely used for slabs made of ordinary concrete, can be used also for the reinforced concrete slabs made of high-strength concrete. Flexural behavior of simply supported slabs in three different sizes were investigated under concentrated load at mid-span. Additionally, behavior of high strength reinforced concrete slabs with 50 mm and 150 mm reinforcement spacings also studied. Failure loads, deflections, experimental and theoretical failure mechanisms were evaluated. The difference between the moments based on yield line theory and experimental moments varied between 1% to 3%. Experimental and analysis results revealed that yield line analysis could conveniently be employed in the analysis of high strength reinforced concrete slabs.

Determination of Yield Line Patterns On the basis of Elastic Fields (탄성해석에 기반한 항복선 형상 추정기법)

  • Song, Jong-Young;Lee, Wan-Su
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • pp.285-292
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    • 2004
  • The objective of this paper is to develop a simplified method to determine yield line patterns of reinforced concrete floor slabs based on the elastic fields. Unlike other methods mainly focused on the plasticity theory, this paper emphasizes the elastic fields, especially principal moments and maximum shears and shows a link between elasticity field and yield line patterns. General criteria on both positive and negative yield lines are suggested in terms of principal moments and maximum shear forces. The proposed method can predict starting point (or regions) of yielding and the further development of yield lines on whole structures. The yield line patterns determined by the proposed method are shown to be coincident with the classical yield line theory. Furthermore, orthotropy in reinforced concrete slab is investigated and yield line patterns for different type of flat slab with non-isotropic strip are studied broadly.

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Ultimate Strength of Concrete Barrier by the Yield Line Theory

  • Jeon, Se-Jin;Choi, Myoung-Sung;Kim, Young-Jin
    • International Journal of Concrete Structures and Materials
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    • v.2 no.1
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    • pp.57-62
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    • 2008
  • When the yield line theory is used to estimate the ultimate strength of a concrete barrier, it is of primary importance that the correct assumption is made for the failure mode of the barrier. In this study, a static test was performed on two full-scale concrete barrier specimens of Korean standard shape that simulate the actual behavior of a longitudinally continuous barrier. This was conducted in order to verify the failure mode presented in the AASHTO LRFD specification. The resulting shape of the yield lines differed from that presented in AASHTO when subjected to an equivalent crash load. Furthermore, the ultimate strengths of the specimens were lower than the theoretical prediction. The main causes of these differences can be attributed to the characteristics of the barrier shape and to a number of limitations associated with the classical yield line theory. Therefore, a revised failure mode with corresponding prediction equations of the strength were proposed based on the yield lines observed in the test. As a result, a strength that was more comparable to that of the test could be obtained. The proposed procedure can be used to establish more realistic test levels for barriers that have a similar shape.

Estimation of the Local Load-Carrying Capacities of CFCT Column to H-Beam Connections by Yield Line Model -With regard to the Tensile side of Beam flange- (인장측 보플랜지의 항복선 모델을 이용한 CFCT기둥-H형강보 접합부의 국부내력평가)

  • Kang, Hyun Sik;Moon, Tae Sup
    • Journal of Korean Society of Steel Construction
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    • v.10 no.3
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    • pp.525-536
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    • 1998
  • This paper is concerned with a theoretical study on the local load-carrying capacities of Concrete-Filled Circular Tubular(CFCT) column to H-beam connections by yield line theory. In this paper, the three cases which are assumed the yield line are involved. The first model is a simplified yield line model. The second model is modified by x and kx factors. The last one is a Morita's model. The local load-carrying capacities of CFCT column to H-beam connections has been studied both experimentally and theoretically using the yield line theory. The purpose of this paper is to suggest the basic data for developing the non-diaphragm connection.

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A Study on the Failure Behavior and the Application of Yield-Line Theory on the Bridge Decks Strengthened by Directional Fiber Plastic (일방향 섬유로 성능향상된 교량 상판의 파괴거동 및 항복선 이론을 적용한 해석적 연구)

  • 심종성;오홍섭;류승무
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.81-86
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    • 2001
  • The concrete bridge decks are in need of replacement and rehabilitation due to decreasing load carrying capacity. In this study, to propose a strengthening technique that improves usability and structural performance of the bridge deck and to propose an efficient strengthening design technique which satisfies both the strength End serviceability of the bridge deck, this paper shows the failure characteristics of the strengthened bridge decks and proposes an empirical yield criterion. Therefore, strengthening efficiency was proposed based on the experiment and yield line analysis result. The yield line theory which adopts the modified criteria of Johansen is considered to predict the ultimate strength about all strengthening material(Carbon Fiber Sheet, Carbon Fiber Rod, Grid Type Carbon Fiber).

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A finite element yield line model for the analysis of reinforced concrete plates

  • Rasmussen, L.J.;Baker, G.
    • Structural Engineering and Mechanics
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    • v.6 no.4
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    • pp.395-409
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    • 1998
  • This paper concerns the development and implementation of an orthotropic, stress resultant elasto-plastic finite element model for the collapse load analysis of reinforced concrete plates. The model implements yield line plasticity theory for reinforced concrete. The behaviour of the yield functions are studied, and modifications introduced to ensure a robust finite element model of cases involving bending and twisting stress resultants ($M_x$, $M_y$, $M_{xy}$). Onset of plasticity is always governed by the general yield-line-model (YLM), but in some cases a switch to the stress resultant form of the von Mises function is used to ensure the proper evolution of plastic strains. Case studies are presented, involving isotropic and orthotropic plates, to assess the behaviour of the yield line approach. The YLM function is shown to perform extremely well, in predicting both the collapse loads and failure mechanisms.

Analysis of Slabs by the Yield Line Theory (강복선이론(降伏線理論)에 의한 슬래브의 해석(解析))

  • Oh, Ju Won
    • Journal of The Korean Society of Civil Engineers
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    • v.8 no.2
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    • pp.51-58
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    • 1988
  • When a R.C. slab is designed by the yield line theory, there is a possibility of local failure caused by an extreme moment distribution on the yield lines. To reduce the local failures the use of the formula in which the plastic resistence moment in the middle strips is different from that in the column strips was suggested. The formula also has a few other parameters for which the values have to be determined to design the R.C. slab. An attempt was made to determine the ideal values of all these parameters. This will make it easy and realistic to design the R.C. slab by the yield line method.

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The Strength of Square Steel Tubular Column to H-beam Connections - Focused on the connections with outside-type diaphragm - (각형강관 기둥 - H형강 보의 접합부 내력 평가 - 외측형 다이아프램 접합부를 중심으로 -)

  • Lee, Seong Do;Kim, Pil Jung;Kim, Kyu Suk
    • Journal of Korean Society of Steel Construction
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    • v.16 no.1
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    • pp.11-20
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    • 2004
  • This paper focused on square steel tubular column to H-beam connections (concrete filled tubular) with an outside-type diaphragm. Based on the yield line theory and the nonlinear static FEM analysis the specification equations were evaluated by comparing them with previous result of the simplified tensile experiment[please check. The yield line theory applied to the mechanical model theory revised by K. Morita, the nonlinear static FEM analysis using abaqus/standard, the ultimate strength equation in the specification equation using the factor for long-time loading, and the yield ratio according to material. The allowable strength in the specification equations applied the safety factors of 2.2 and 2.6 in the cases with and without filled concrete, respectively. Therefore, the evaluation of strength(for the previous result of the simplified tensile experiment in this study) was considered possible through the yield line theory, the nonlinear static FEM analysis, and the specification equations. Likewise, the specification equations were seen to be an underestimate of the previous result of the simplified tensile experiment. The strength and displaced mesh in the FEM analysis approximated the previous result of the simplified tensile experiment.

Inclined yield lines in flange outstands

  • Bambach, M.R.
    • Structural Engineering and Mechanics
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    • v.29 no.6
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    • pp.623-642
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    • 2008
  • While spatial plastic mechanism analysis has been widely and successfully applied to thinwalled steel structures to analyse the post-failure behaviour of sections and connections, there remains some contention in the literature as to the basic capacity of an inclined yield line. The simple inclined hinge commonly forms as part of the more complex spatial mechanism, which may involve a number of hinges perpendicular or inclined to the direction of thrust. In this paper some of the existing theories are compared with single inclined yield lines that form in flange outstands, by comparing the theories with plate tests of plates simply supported on three sides with the remaining (longitudinal) edge free. The existing mechanism theories do not account for different in-plane displacement gradients of the loaded edge, nor the slenderness of the plates, and produce conservative results. A modified theory is presented whereby uniform and non-uniform in-plane displacements of the loaded edge of the flange, and the slenderness of the flange, are accounted for. The modified theory is shown to compare well with the plate test data, and its application to flanges that are components of sections in compression and/or bending is presented.

Analysis of Deformation and Residual Curvature of Steel Sheets in Strip Process Lines (박강판 제조공정에서의 소재 굽힘변형과 잔류만곡 발생 해석)

  • 박기철;전영우;정기조
    • Transactions of Materials Processing
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    • v.6 no.2
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    • pp.118-135
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    • 1997
  • In order to analyze the deformation and residual curvature of steel sheets in the strip processing lines, a program for calculating curvature and work hardening of sheet was developed. Strip deformation caused by repeated bending under tension in the process lines was analyzed on the basis of the incremental-plasticity theory with the mixed hardenting model for the purpose of predicting the strip shape and the yield stress change. The developed calculation program was applied to predict curl and gutter of sheets within a 10% difference. The yield stress increment was also predicted with the similar accuracy. Application of the model to tension legvelling process showed that gutter could be controlled by intermesh and elongation. The yield stress increment in the electro-galvanizing line calculated by the developed program was found to be dependent on the yield strength, the applied tension and the diameter of the smallest roll.

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