• Proceedings of the Korea Concrete Institute Conference
• /
• 2008.11a
• /
• pp.221-224
• /
• 2008

A secant stiffness linear analysis method was developed for moment redistribution of moment-resisting frames. In the proposed method, rotational spring models are used for plastic hinges of the members whose flexural moments are needed to be redistributed. At the plastic hinges, secant stiffness is used to address the effect of the flexural stiffness reduced by inelastic deformation. Linear analysis is repeated with adjusted secant stiffness until the flexural equilibrium is satisfied in the structure and members. By using the secant stiffness analysis, the effect of the inelastic deformation on the moment redistribution can be considered. Further, the safety of plastic hinges can be evaluated by comparing the inelastic rotation resulting from the secant stiffness analysis with the rotational capacity of the plastic hinges. For verification, the proposed method was applied to a continuous beam tested in previous study. A application example for a multiple story moment-resisting frame was presented.

• Journal of Korean Society of Steel Construction
• /
• v.19 no.6
• /
• pp.715-723
• /
• 2007

A displacement-based seismic design procedure was proposed for mid-to-low-rise steel moment frames. The proposed method was totally different from the current R-factor approach in that it directly uses available connection rotation capacity as a primary design variable. To this end, the relationship between available connection rotation capacity and seismic response modification (R factor) was established first; this relationship has been a missing link in current ductility-based design practice. A step-by-step displacement-based iterative design procedure was then proposed and verified using inelastic dynamic analysis.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.20 no.5
• /
• pp.35-43
• /
• 2016

In order to understand rotation behavior of high strength steel endplate connections under fire, this study is compared with existing studies conducted using FEA program. Eurocode 3 presents the three failure modes according to the prediction of bending resistance moment. The parameters of analysis model are temperature, thickness and steel materials of endplate. The rotation stiffness, and bending resistance moment are analyzed according to the parameters. The change of rotation stiffness and bending resistance moment are analyzed about the parameters, regression equations are suggested the change of high strength steel endplate connections. Consequently, the regression equations were proposed as the linear and quadratic equation. The moment ratio of high strength steel under fire was more reduced than the carbon steel, and was small effect about the thickness. When the high strength steel under fire was compared with at ambient temperature, the slope of initial rotation stiffness reduced, the increment ratio of moment was slow, and the change of plastic rotation stiffness wasn't effect by the thickness increase.

• Proceedings of the KWS Conference
• /
• 2004.05a
• /
• pp.159-161
• /
• 2004

FSW공전은 특수하게 설계된 용접툴(tool)을 특정한 회전수로 회전시키면서 용접하고자하는 재료의 용접라인에 삽입하여 용접에 필요한 마찰열과 소성변형을 발생시키고, 그 후 용접라인을 따라 툴을 이동시킴으로써 용접이 이루어지는 매우 간단한 공정이다. (중략)

• Computational Structural Engineering
• /
• v.23 no.3
• /
• pp.69-74
• /
• 2010

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.7 no.4
• /
• pp.91-97
• /
• 2003

The maximum moment may occur at interior supports of continuous bridges. If the bigger moment is applied on them, a local yielding at interior supports may occur. They may show plastic behaviors, and the moment will be redistributed. The strength design, L.F.D., redistributes 10% of the negative moment which is obtained from the elastic analysis. However, A.L.F.D method computes the moment which is redistributed. This moment is called automoment. The moment-rotation curve is needed to find automoment. In this paper moment-rotation curve for compact sections suggested from AASHTO Guide Specifications is used to find automoment. Based on A.L.F.D. limit states specification method, a three-span continuous bridge is designed.

• Journal of Korean Society of Steel Construction
• /
• v.23 no.5
• /
• pp.547-555
• /
• 2011

An unstiffened top and seat angle connection is a type of partially restrained connection that is suitable for low- and medium-rise steel buildings. The plastic moment resisting capacity of such connection is needed in practical design, in addition to the accurate prediction of the initial rotational stiffness. Therefore, most of the studies conducted for the mentioned connections were performed to predict the initial stiffness and the plastic moment resisting capacity with varying geometric properties. The main parameters of such experimental tests were the thickness and high-strength bolt gauge distance of AISC LRFD-type A top and seat angle connections. Based on the test results, the analytical model was also proposed in this study. The applicability of the proposed model was verified by comparing the test results from this study with those of other studies.

• Journal of Korean Society of Steel Construction
• /
• v.20 no.5
• /
• pp.625-632
• /
• 2008

In the companion paper (Model Development), an analytical model estimating the available rotation capacity of fully restrained beam-column connections in special steel moment-resisting frames was proposed. In this paper, two limit states were considered as the connection rotation capacity criteria: (i) strength degradation failure when the strength falls below the nominal plastic strength due to the local buckling of the beam's cross-section and (ii) low-cycle fatigue fracture caused by plastic strain accumulation at the buckled flange after only a few cycles of high-amplitude deformation. A series of analyses are conducted using the proposed model with two limit states under monotonic and cyclic loadings. Beam section geometric parameters, such as flange and web slenderness ratios, varied over the practical ranges of H-shapedbeams to observe their effect on the rotation capacity and low-cycle fatigue life of pre-qualified WUF-W connections.

• Journal of the Korean Ceramic Society
• /
• v.11 no.4
• /
• pp.5-18
• /
• 1974

본 연구에 있어서는 연료유의 연소에 의한 내화물의 부식을 연구하기 위하여 시멘트소성용 회전가마, 보일러 및 판유리제조용 탱크가마에 쓰이는 여러 내화물을 짤라서 그 가운데에 구멍을 파고 중유재의 주성분인 V2O5, Na2CO3, Fe2O3, Fe 및 황산철을 미리 그 구멍속에 넣어 응용 확산시킨 다음 이들을 그들의 상용온도인 145$0^{\circ}C$로 황 함유량이 다른 연류유로 소성하여 얻은 결과는 다음과 같다. 일반적으로 5산화 바나듐-알루미나, 고알루미나질 및 염기성 내화물; 산화나트륨-고알루미나질, 실리마나이트질 및 염기성 내화물은 2%미만의 황 함유 연류유소성에 의하여 부식이 적고 3.5%이상의 황하유 연료유소성시는 황에 의하여 대개가 침식을 당하였다. 무수 아황산 분위기속에서 규산알루미늄 및 구석계의 내화점토질내화물은 산화철이 환원되어 색이 연해지고 고알루미나질 벽돌은 색이 짙어지는 경향이 있고 산화철은 황산철로 변하여 풍화의 원인이 되어 침식을 당하게 되었고, 소성시간이 길면 길수록 부식은 증가하고 황산소다보다 탄산소다에 의하여 훨씬 더 많이 부식을 당하였다.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.14 no.8
• /
• pp.4028-4032
• /
• 2013

Recycling method for pyrolyzed carbon black from pyrolysis process of waste tires is needed. Carbon black from pyrolysis of waste tires was used to modify and improve the permanent deformation properties of asphalt binder. 0%, 5%, 10%, 15% and 20% of pyrolyzed carbon black was mixed. Couple of laboratory tests, such as softening point, flash point test, rotational viscometer test and dynamic shear rheometer test, were carried out. The use of pyrolyzed carbon black incresed the softening point, rotational viscosity at 135oC, and resistance of permanent deformation.