• Steel and Composite Structures
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• 제42권3호
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• pp.325-351
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• 2022

This paper studies the lateral impact behavior of ultra-high performance fiber-reinforced concrete (UHPFRC) filled double-skin steel tubular (UHPFRCFDST) columns. The impact force, midspan deflection, and strain histories were recorded. Based on the test results, the influences of drop height, axial load, concrete type, and steel tube wall thickness on the impact resistance of UHPFRCFDST members were analyzed. LS-DYNA software was used to establish a finite element (FE) model of UHPFRC filled steel tubular members. The failure modes and histories of impact force and midspan deflection of specimens were obtained. The simulation results were compared to the test results, which demonstrated the accuracy of the finite element analysis (FEA) model. Finally, the effects of the steel tube thickness, impact energy, type of concrete and impact indenter shape, and void ratio on the lateral impact performances of the UHPFRCFDST columns were analyzed.

• 한국강구조학회 논문집
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• 제20권6호
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• pp.783-792
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• 2008

최근 초고층 건축물의 수요에 대응하여 고성능 고강도 강재에 대한 수요가 급증하고 있으며 고층건축물에 대한 지진 피해에 대한 인식이 확산되면서 건축구조용강에 대한 요구 성능이 점차 증가하는 추세이다. 이러한 수요에 의해 600MPa 급 강재가 출현 되었으며 현재 강교량 및 초고층 건축물에 적용하려고 많은 연구가 이루어지고 있다. 새로운 강재를 적용한 골조의 수평력에 대한 거동은 자료가 부족한 실정이다. 특히 인성에 관해서는 일반구조용 강재를 적용한 기둥 보 접합부의 소성변형율과 비교하여 고강도강을 적용한 기둥보 접합부의 소성변형율 관련 설계자료가 절실히 필요하다. 따라서 본 연구에서는 600MPa급(SM570 TMC) 강재를 적용한 기둥-보 접합부의 초기연구로서 논스캘럽과 추천형스 캘럽 상세의 실구조물 규모의 기둥-보 용접접합부 실험체를 제작, 내진성능실험을 통해 구조성능을 평가하였다. 기존의 일반구조용 SM490 강재를 적용한 기존의 연구와 비교 분석하여 초고층 건축물에 적용을 위한 내진설계자료 및 제작상의 주의사항을 제시하였다.

• Earthquakes and Structures
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• 제7권4호
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• pp.527-552
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• 2014

The development of modern concrete technology makes it much easier to produce high-strength concrete (HSC) or ultra-high-strength concrete (UHSC) with high workability. However, the application of this concrete is limited in practical construction of traditional reinforced concrete (RC) structures due to low-ductility performance. To further push up the limit of the design concrete strength, concrete-filled-steel-tube (CFST) columns have been recommended considering its superior strength and ductility performance. However, the beneficial composite action cannot be fully developed at early elastic stage as steel dilates more than concrete and thereby reducing the elastic strength and stiffness of the CFST columns. To resolve this problem, external confinement in the form of steel rings is proposed in this study to restrict the lateral dilation of concrete and steel. In this paper, a total of 29 high-strength CFST (HSCFST) columns of various dimensions cast with concrete strength of 75 to 120 MPa concrete and installed with external steel rings were tested under uni-axial compression. From the results, it can be concluded that the proposed ring installation can further improve both strength and ductility of HSCFST columns by restricting the column dilation. Lastly, an analytical model calculating the uni-axial strength of ring-confined HSCFST columns is proposed and verified based on the Von-Mises and Mohr-Coulomb failure criteria for steel tube and in-filled concrete, respectively.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2004년도 추계 학술발표회 제16권2호
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• pp.341-344
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• 2004

In the present research, slump, modulus of rupture (MOR) and flexural toughness $(I_{30})$ of high performance hybrid fiber reinforced concrete (HPHFRC) mixed with micro-fiber (carbon fiber) and macro-fiber (steel fiber) and replaced with silica fume were assessed with the analysis of variance (ANOVA). Steel fiber was a considerable significant factor in aspect of the response values of MOR and boo Based on the significance of factors related to response values from ANOVA, following assessments were available; Slump decrease: carbon fiber >> steel fiber > silica fume; MOR: steel fiber > silica fume > carbon fiber; $I_{30}$: steel fiber > carbon fiber > silica fume. Steel fiber $1.0\%$, carbon fiber $0.25\%$ and silica fume $5.0\%$, and Steel fiber $1.0\%$, carbon fiber $0.25\%$ and silica fume $2.5\%$ were obtained as the most optimum mixture.

• Steel and Composite Structures
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• 제9권2호
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• pp.159-172
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• 2009

Two prestressed steel reinforced high performance concrete (SRC) beams, a nonprestressed SRC beam and a counterpart prestressed concrete beam were tested under low reversed cyclic loading to evaluate seismic performance of prestressed SRC beams. The failure modes, deformation restoring capacity, ductility and energy dissipation capacity of the prestressed SRC beams were discussed. Results showed that due to the effect of plastic deformations of steel beams encased in concrete, the three SRC beams exhibited residual deformation ratios ranging between 0.64 and 0.79, which were apparently higher than that of the prestressed concrete beam (0.33). The ductility coefficients of the prestressed SRC beams and the prestressed concrete beam ranged between 4.65 and 4.87, obviously lower than that of nonprestressed SRC beam (9.09), which indicated the steel beams influenced the ductility little while prestressing resulted in an apparent reduction in ductility. The amount of energy dissipated by the prestressed SRC beams was less than that dissipated by the nonprestressed SRC beam but much more than that dissipated by the prestressed concrete beam.

• Steel and Composite Structures
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• 제31권3호
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• pp.303-317
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• 2019

This paper presents a finite element model for predicting the behaviour of high-strength steel bolted beam-to-column joints under monotonic loading. The developed numerical model considers the effects of material nonlinearities and geometric nonlinearities. The accuracy of the developed model is examined by comparing the predicted results with independent experimental results. It is demonstrated that the proposed model accurately predicts the ultimate flexural resistances and moment-rotation curves for high-strength steel bolted beam-to-column joints. Mechanical performance of three joint configurations with various design details is examined. A parametric study is carried out to investigate the effects of key design parameters on the behaviour of bolted beam-to-column joints with double-extended endplates. The plastic flexural capacities of the beam-to-column joints from the experimental programme and numerical analysis are compared with the current codes of practice. It is found that the initial stiffness and plastic flexural resistance of the high-strength steel beam-to-column joints are overestimated. Proper modifications need to be conducted to ensure the current analytical method can be safely used for the bolted beam-to-column joints with high-performance materials.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2012년도 추계 학술논문 발표대회
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• pp.201-202
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• 2012

Recently, High-Strength steel reinforcement has been studied throughout the internal and external. One of the advantages using High-Strength steel reinforcement in construction is the economic effect due to the decreasing of its quantity. Also, another good effect is the increases of workability by reason of reducing the congestion. But, realistically it is not used in nuclear power plant construction site because of the restriction of design standard. The purpose of this report secures the reliability and changes the code through the performance evaluation test of the wall using the high-strength steel reinforcement in nuclear power plant.

• 토지주택연구
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• 제7권1호
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• pp.31-41
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• 2016

이 논문은 최근 천영수 등(2011)에 의하여 제안된 벽체 단부 횡보강상세를 지닌 벽체를 중심으로 벽체의 구조성능 영향 변수들을 대상으로 한 실험결과와 그에 따른 내진거동 및 이력특성을 제시하고 있다. 제시된 결과는 동 벽체의 비선형이력특성을 규명함으로써 향후 성능기반설계의 적용을 위한 기초자료를 제공하게 될 것이다. 실험결과, 제안된 횡보강 상세를 채용한 실험체의 균열 및 파괴 양상은 축력과 내진철근의 적용 여부와 상관없이 유사한 경향을 나타내었으며, 기준에서 제시하고 있는 설계식에 의하여 실험체의 최대강도를 잘 예측할 수 있는 것으로 나타났다. 또한, 축력이 높을 수록 초기강성과 최대강도는 증가하나 변형능력은 떨어지는 경향이 있어 고 축력으로 인한 변형능력 감소에 대한 고려가 필요할 것으로 보이며, 고 축력이 작용하는 벽체의 경우 내진철근의 사용이 변형능력의 확보라는 관점에서 매우 효과적인 방안이 될 것으로 보임으로 가능하다면 소성힌지 영역은 내진철근을 사용한 경계요소로 보강하는 것이 바람직한 것으로 판단된다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2011년도 제42회 하계학술대회
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• pp.812-813
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• 2011

This paper presents the characteristic of newly developed electrical steel and motor performance analysis for HEV/EV. This material is developed and optimized for high frequency operation to reduce the core losses in traction motors to increase fuel efficiency. Four types of electrical steel are introduced, which are optimized for high flux density (PNHF), high frequency low core loss (PNF), high punchability (PNS) and high strength (PNT) to meet different specifications from different types of traction motors. To identify the motor performance with this material, finite element analysis was used to calculate core loss as well as Ld and Lq for efficiency map. Also structure analysis was performed to calculate stress on bridge rotor.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 추계 학술발표회 논문집
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• pp.633-636
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• 2006

High-rise and large size buildings require high strength concrete and steel structure as a necessity. However, high strength concrete and steel structure are strong material but have a weakness to high temperature. Therefore, fire protection is a matter that must be considered very importantly in design for structure of high strength concrete and steel. Fire proof board that is existing method for fire proof has relatively low performance in fire protection emphasizes the need of new fire protection material due to the using of in numerable inflammables like plastics. The objective of this study is to understand the fire-resisting performance of newly developed fire protection material for building. This paper describes the results of fire tests using ISO curve that is fire protection regulation for buildings of the newly developed cementitious fire protection coating material applied concrete tunnel lining specimens.