• Steel and Composite Structures
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• 제23권4호
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• pp.421-433
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• 2017

Experimental and numerical studies of a newly developed Reduced Beam Section (RBS) connection, called Tubular Web RBS connection (TW-RBS) have been recently conducted. This paper presents experimental and numerical results of extending the plastic hinge length on the beam flange to increase energy dissipation of a proposed version of the TW-RBS connection with two pipes, (TW-RBS(II)), made by replacing a part of flat web with two steel tubular web at the desirable location of the beam plastic hinge. Two deep-beam specimens with two pipes are prepared and tested under cyclic loads. Obtained results reveal that the TW-RBS(II) like its type I, increases story drift capacity up to 6% in deep beam much more than that stipulated by the current seismic codes. Based on test results, the proposed TW-RBS(II) helps to dissipate imposed energy up to 30% more than that of the TW-RBS(I) specimens at the same story drift and also reduces demands at the beam-to-column connection up to 30% by increasing plastic hinge length on the beam flange. The TW-RBS(II) specimens are finally simulated using finite element method showing good agreement with experimental results.

• 한국자동차공학회논문집
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• 제4권6호
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• pp.216-222
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• 1996

This paper presents a computational technique to predict roof crush resistance in early design stage of passenger car development. This technique use a simple F.E. model with nonlinear spring elements which represent plastic hinge behavior at weak areas. By assuming actual sections as equivalent simple sections, maximum bending moments which weak areas in major members can stand are theoretically calculated. Results from prediction of roof crush resistance are correlated well with test results.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1999년도 학회창립 10주년 기념 1999년도 가을 학술발표회 논문집
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• pp.553-556
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• 1999

In this dissertation, experimental research was carried out to study the hysteretic behavior of reinforced high-strength concrete beam-column joints designed by high performance techniques, such as application of high-strength concrete, reducing of joint regions damage, moving of beam plastic hinge. Specimens(HJAI, HJCI), designed by the development of earthquake-resistant performance, moving of beam plastic hinge, and new design approach, were attained the moving of beam plastic hinge and developed significantly earthquake-resistant performance of such joints.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2003년도 봄 학술발표회 논문집
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• pp.77-84
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• 2003

In this paper, the refined plastic-hinge analysis accounting for the effect of strain reversal caused by non-proportional loading is developed. This analysis accounts for material and geometric nonlinearities of the structural system and its component members. Moreover, the problem, conventional refined plastic-hinge analyses have underestimated the strength of structures subjected to non-proportional loading, is overcome. The modified stiffness degradation model approximating the effect of strain reversal is discussed in detail. The proposed analysis is verified by the comparison of the finite element analysis. A case study shows that the effect of strain reversal 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.

• Computers and Concrete
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• 제32권2호
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• pp.139-148
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• 2023

The purpose of this paper is to numerically assess the seismic performance of deteriorated reinforced concrete columns using a new plastic-hinge element. Developing a three dimensional (3D) nonlinear model can be difficult and computationally complex, and there can be problems applying it in the field. Thus, to solve these problems, a plastic-hinge element that could considers the shear deformation of deteriorated reinforced concrete columns was proposed. The developed element was based on the Timoshenko beam model and used two nodes with six degrees of freedom and a zero-length element. Moreover, the developed model could consider the combined effects of corrosion, as demonstrated by the reduced reinforcement area and the loss of bond. Consequently, the numerical procedures developed for evaluating the seismic performance of deteriorated columns were validated by comparing the verification results.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2010년도 추계 학술발표회
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• pp.349-356
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• 2010

In this study, a new design method of pile bent structure considering plastic hinge was proposed on the basis of the beam-column model. Based on the analysis results, it is found that the positioning of plastic hinge on the pile bent structure was influenced by nonlinear behavior of material and p-$\Delta$ effect. Moreover, concrete cracking began to occur at the joint section between the pile and column in case of pile bent structure with different cross-sections. The plastic hinge can be developed on the pile bent structure when large displacement was occurred, and pile bent structures can be maintained well only if it is developed on the column part. Therefore, in this study, the optimized cross-section ratio between column and pile was analyzed to induce the plastic hinge at the joint section between the pile and column. Based on this, the optimized diameter ratio of pile and column can be obtained below the inflection point of the bi-linear curve depending on the relations between column-pile diameter ratio($D_c/D_p$) and normalized lateral cracking load ratio($F/F_{Dc=Dp}$). And through this study, it is founded that in-depth limit($L_{As}$=0.4%) normalized by the pile length($L_P$) are proportionally decreased as the pile length($L_P/D_P$) increases up to $L_P/D_P$=17.5, and beyond that in-depth limit converges to a constant value. Finally, it is found that the proposed limit depth by taking into account the minimum concrete-steel ratio would be more economical design of the pile bent structure.

• Structural Engineering and Mechanics
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• 제72권6호
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• pp.675-687
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• 2019

As the bridges are an integral part of the transportation network, their function as one of the most important vital arteries during an earthquake is fundamental. In a design point of view, the bridges piers, and in particular the wall piers, are considered as effective structural elements in the seismic response of bridge structures due to their cantilever performance. Owing to reduced seismic load during design procedure, the response of these structural components should be ductile. This ductile behavior has a direct and decisive correlation to the development of plastic hinge region at the base of the wall pier. Several international seismic design codes and guidelines have suggested special detailing to assure ductile response in this region. In this paper, the parameters which affect the length of plastic hinge region in the reinforced concrete bridge with wall piers were examined and the sensitivity of these parameters was evaluated on the length of the plastic hinge region. Sensitivity analysis was accomplished by independently variable parameters with one standard deviation away from their means. For this aim, the Monte Carlo simulation, tornado diagram analysis, and first order second moment method were used to determine the uncertainties associated with analysis parameters. The results showed that, among the considered design variables, the aspect ratio of the pier wall (length to width ratio) and axial load level were the most important design parameters in the plastic hinge region, while the yield strength of transverse reinforcements had the least effect on determining the length of this region.

• 콘크리트학회지
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• 제10권4호
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• pp.93-100
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• 1998

본 논문은 고성능 철근콘크리트 보의 휨강성, 소성힌지 길이 및 소성힌지의 회전능력에 관한 연구이다. 실험은 철근비, 콘크리트 강도 및 하중 재하형태(1점가력과 2점가력)를 변수로 하여 총 15개의 철근콘크리트 단순보에 대하여 행하여 졌다. 콘크리트의 실린더 압축강도가 700kg/${cm}^2$, 슬럼프 20~25 cm 및 슬럼프 플로우가 60~70cm인 고성능 철근콘크리트 및 보통 강도 철근콘크리트 단순보의 휨실험결과, 본 실험의 경우에 고성능 철근콘크리트 보의 극한 곡률을 구할 때는 ${\varepsilon}_{cu}=0.0047$의 값을 사용할 수 있는 것으로 나타났다. 고성능 철근콘크리트 단순보의 휨강성을 평가하기 위해 유효단면 2차 모멘트를 구하는 식과 고성능콘크리트 단순보에 2점 하중을 가하는 경우 등가 소성힌지 길이를 구하는 식이 본 실험의 경우에 대해서 제시되었다. 극한 모멘트 상태에서 이러한 식을 사용하여 구한 처짐값은 실험값과 비교적 일치하게 나타났다.

• Earthquakes and Structures
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• 제5권6호
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• pp.679-702
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• 2013

During an earthquake, soils filter and send out the shaking to the building and simultaneously it has the role of bearing the building vibrations and transmitting them back to the ground. In other words, the ground and the building interact with each other. Hence, soil-structure interaction (SSI) is a key parameter that affects the performance of buildings during the earthquakes and is worth to be taken into consideration. Columns are one of the most crucial elements in RC buildings that play an important role in stability of the building and must be able to dissipate energy under seismic loads. Recent earthquakes showed that formation of plastic hinges in columns is still possible as a result of strong ground motion, despite the application of strong column-weak beam concept, as recommended by various design codes. Energy is dissipated through the plastic deformation of specific zones at the end of a member without affecting the rest of the structure. The formation of a plastic hinge in an RC column in regions that experience inelastic actions depends on the column details as well as soil-structure interaction (SSI). In this paper, 854 different scenarios have been analyzed by inelastic time-history analyses to predict the nonlinear behavior of RC columns considering soil-structure interaction (SSI). The effects of axial load, height over depth ratio, main period of soil and structure as well as different characteristics of earthquakes, are evaluated analytically by finite element methods and the results are compared with corresponding experimental data. Findings from this study provide a simple expression to estimate plastic hinge length of RC columns including soil-structure interaction.

• 콘크리트학회논문집
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• 제22권6호
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• pp.825-832
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• 2010

철근콘크리트 구조물은 위험 단면이 휨강도에 도달하더라도 이 단면에서 소성힌지가 형성되어 휨모멘트가 재분배되어 곧바로 파괴에 도달하지 않는다. 이러한 소성힌지 영역에서 발생하는 비탄성 변형에 의해 소성 회전이 발생한다. 소성힌지길이는 주로 재료 특성에 영향을 받는다. 이 연구에서는 유로코드2에서 제시하고 있는 재료 모델로부터 산정된 휨곡률 분포로부터 소성힌지길이와 소성회전각을 일관되게 산정하였다. 재료 모델의 한계값 즉, 콘크리트 극한변형률, 철근 극한변형률 및 철근의 경화비(k)가 소성회전능력에 미치는 영향을 분석하였다. 해석 결과 콘크리트 극한변형률 및 철근 극한변형률이 증가함에 따라 소성회전능력이 증가하였고 특히, 철근의 경화비(k)가 증가함에 따라 소성 회전각은 크게 증가되는 것으로 나타났다. 따라서 각 재료 모델의 한계값 결정에 세심한 주의가 필요할 것으로 나타났다.