• Journal of Korean Society of Steel Construction
• /
• v.20 no.5
• /
• pp.633-644
• /
• 2008

The structural framework design uses high-strength bolts and welding in column splices. However, for the column under high compression, the number of the required high-strength bolts can be excessive and the increase of welding results in difficulty of quality inspection, the transformation of the structural steels, and the increase of erection time. According to the AISC criteria, when columns have bearing plates, or they are finished to bear at splices, there shall be sufficient connections to hold all parts securely in place. The Korean standard sets the maximum 25% of the load as criteria. Using direct contact makes it possible to transfer all compressive force through it. The objective of this study is to examine the generally applied stress path mechanism of welded or bolted columns and to verify the bending moment and compression transfer mechanism of the column splice according to metal touch precision. For this study,22 specimens of various geometric shapes were constructed according to the change in the variables for each column splice type, which includes the splice method, gap width, gap axis, presence or absence of splice material, and connector type. The results show that the application of each splice can be improved through the examination of the stress path mechanism upon metal contact. Moreover, the revision of the relative local code on direct contact needs to be reviewed properly for the economics and efficiency of the splices.

• Electronics and Telecommunications Trends
• /
• v.30 no.6
• /
• pp.68-78
• /
• 2015

우리의 일상생활 속에서 일어나는 수많은 일이 네트워크를 배제하고는 설명할 수 없을 정도로 삶과 밀접한 관계를 가지고 있다. 그러나 이러한 네트워크의 근간이 되는 국내 네트워크 장비 산업의 현실은 그리 낙관적이지 않다. 대표적인 이유로 핵심 소프트웨어인 네트워크 운영체제의 부재를 꼽는다. 이는 소프트웨어 개발 인력 부재, 투자 부족, 산업 경쟁력 약화, 매출 축소 등이 악순환의 고리로 연결되기 때문이다. 따라서 본고에서는 네트워크 산업 생태계의 회복과 이를 통한 네트워크 산업의 재도약을 위한 핵심 분야인 네트워크 운영체제의 기술동향을 살펴보고자 한다. 먼저 국내외 통신산업의 변화와 네트워크 운영체제 개발동향 및 네트워크 운영체제의 요구사항을 확인하고, 최근 주목받고 있는 개방형 네트워크 장비 개발동향를 소개한다. 그리고 국내외 네트워크 장비 시장에서 경쟁력을 확보하려는 방안으로 추진하고 있는 한국형 네트워크 운영체제(openN2OS)의 개발현황을 살펴본다.

• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 2009.04a
• /
• pp.84-87
• /
• 2009

본 논문에서는 최근 초고층 건축물에 많이 활용되어지는 기둥-가새 시스템인 다이아그리드 시스템을 활용하여 중저층 건축물에 적용가능성을 평가하였다. 본 시스템은 튜브구조의 형태로 횡력에 대한 저항력이 우수하며 중력하중과 황하중을 기초와 지반에 안전하게 하중을 전달한다. 다이아그리드는 경사기둥과 보를 반복적으로 삼각형 형태로 배치되어 중력하중을 받을 경우 수직부재는 압축력을 보는 인장력을 받게 된다. 경사기둥과 보를 연결하는 접합부는 H-형강으로 설계 시 제작이 복잡하고 외관이 좋지 않다. 하지만 원형강관을 사용 할 경우 복합하지 않은 형태로 설계가 가능하고 외관이 우수하기 때문에 외부에 노출이 가능해진다. 또한 원형강관은 개방형 단면 부재에 비해 압축좌굴과 비틀림에 대한 성능 등이 우수하여 구조적인 성능이 우수하다. 원형강관을 이용하여 다이아그리드 시스템이 고층 건축물 뿐만 아니라 중저층 건축물에도 적용 타당성을 검토하였으며 원형강관 접합부 설계는 한계상태설계법이 사용 된 KBC2008(안)을 이용하여 설계하였다.

• Computational Structural Engineering
• /
• v.11 no.4
• /
• pp.177-186
• /
• 1998

PSC 연속 평판슬래브의 설계는 부정정 평판슬래브에 대한 정확한 해석의 어려움 등으로 등가보이론과 등가골조이론에 의한 근사식을 수정없이 사용하거나 컴퓨터를 이용한 해석에 의존하고 있으나 해석결과를 간단하게 정확히 평가할 수 있는 기법은 없는 실정이다. 또한 PSC 연속 평판슬래브의 부재력은 긴장재의 곡선형태에 따라 변하므로 실제 설계시 PS 긴장재의 정확한 곡선식을 찾는 것은 매우 중요하다. 본 연구에서는 비부착 PSC 연속 평판슬래브를 설계할 때 기둥과 기둥을 연결하는 PS 긴장재의 기하학적 곡선형태를 결정하는 방법과, PS 긴장력으로 인해 발생하는 평판슬래브의 기둥부 휨모멘트에 대하여 판이론을 기초로 간편하게 계산하는 방법을 제안하였다. 본 연구에서 제안된 이론으로 계산된 PSC 연속 평판슬래브에 대한 해석값과 유한요소 해석에 의한 지점 부모멘트를 비교 검토하여, 본 논문에서 제시한 기법의 타당성을 입증하였다. 따라서 본 연구는 설계자에게 컴퓨터의 해석결과를 간단하고 정확하게 검증할 수 있도록 하였다.

• Journal of the Korea Concrete Institute
• /
• v.26 no.4
• /
• pp.533-543
• /
• 2014

Currently, composite construction of prestressed Precast Concrete (PC) and Cast-In-Place (CIP) concrete with different concrete strengths are frequently used in the modular construction. However, current design codes do not clearly define shear design methods for such composite beams. In this present study, simply supported prestressed PC-CIP composite beams without vertical shear reinforcement or only with horizontal shear reinforcement were tested to evaluate the effect of prestressing on the shear strength and the shear design method for such composite members. The test variables were the area ratio of PC and CIP concretes, prestressing force, shear span-to-depth ratio, and shear reinforcement ratio. The results showed that the shear strength was increased by the increase of prestressing force and prestressed PC area, and the decrease of shear span-to-depth ratio.

• Magazine of the Korea Concrete Institute
• /
• v.11 no.2
• /
• pp.157-165
• /
• 1999

When the ultimate strength of a concrete flexural member is evaluated, the effect of member size is usually not considered. For various types of loading, however, the strength always decreases with the increment of member size. In this paper the size effect of a flexural compression member is investigated by experiments. For this purpose, a series of C-shaped specimens subjected to axial compressive load and bending moment was tested using three different sizes of specimens with a compressive strength of 528 kg/$cm^2$. According to test results the size effect on flexural compressive strength was apparent, and more distinct than that for uniaxial compressive strength of cylinders. Finally a model equation was derived using regression analyses with experimental data.

• Journal of the Society of Naval Architects of Korea
• /
• v.37 no.3
• /
• pp.90-98
• /
• 2000

Nesting and cutting path optimization have a great effect on price competitions and improvement of productivity in various industries such as the shipbuilding, the auto, the clothing, and so on. But the theoretical approach on the development of cutting path optimization algorithm, which can be applied effectively in the shipbuilding, has not been performed enough because parts are so complex and various. In this study, a new solution has been presented to solve the cutting path problem in 2-D cutting by using improved genetic algorithm. The presented optimization algorithm can search not only the cutting sequence of parts but also the position of piercing point by applying the effective neighborhood solution generating method

• Journal of Korean Society of Steel Construction
• /
• v.13 no.2
• /
• pp.133-141
• /
• 2001

A tubular member holding an axially through-gusset connection is often used to transmit axial compression in a steel truss structures. The elastic buckling loads of the member is affected by the stiffness ratio($\beta$) and the length ratio(G) because of two elements with different properties. In current code, however, the strength is evaluated with an effective length factor k=0.9 without considering the above effect. Therefore this study analyzed a theoretical mechanism based on the elasticity theory and performed a finite element analysis to investigate the influence parameters on the elastic buckling strength of axially loaded member.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.10 no.3
• /
• pp.19-28
• /
• 1990

The main purpose of this paper is to present both fundamental and some higher natural frequencies of catenary arcs. The differential equations governing planar free vibrations for these arcs are derived, in which the rotatory inertia is included, as non-dimensional forms and solved numerically to obtain frequencies and mode shapes. The hinged-hinged and clamped-clamped end constraints are applied in numerical examples. The lowest four natural frequencies are reported as the functions of non -dimensional system parameters; the slenderness ratio and the rise to span length ratio. The effects of rotatory inertia on natural frequencies are reported and some typical mode shapes are also presented.

• Proceeding of KASS Symposium
• /
• 2006.05a
• /
• pp.66-72
• /
• 2006

Recently nonlinear materials are used in construction of building and bridge then various structure formats are achieved positively. one of them, cable members, are the interesting study object which increase rigidity of a total structure by inducing tension. The way of construction using cable members is increasing, so the technology of design and construction are developing. Protection Fretting Fatigue is very important to maintain efficiency of cable member permanently. However, recognition of this is somewhat humble and this paper considers anti-corrosive performance of cable.