Deok Hee Won

Performance Evaluation of the Column-Coping Joint for Prefabricated DSCT Pier

Recently, Technology of bridge construction has made great progress for reduction of construction period and Green Growth. The construction period of Pier had about 50% in construction period of entire bridge. Therefore, construction method of prefabricated piers have researched by many researchers, lately. In this paper, we suggested the joint of coping-column for prefabricated DSCT pier and verified by experimental study. To experimental study, the test methods had proposed for the performance characteristics evaluation of coping-column joint. Test methods were made up cyclic eccentricity loading test and static compressive loading test. We had produced the major parameters and suggested the standard model for joint of coping-column through the experimental study.

Buckling Behavior of Circular Steel Tubes under Fire

Recently, several lives were lost because of the collapse of structures under fire. Steel members are mainly used in the columns and beams of buildings for improving construction efficiency. The fire resistance of steel structure is very important because when it don’t have fire resistive covering, it rapidly changes with high temperature. In fire resistance design of steel, steel structure must have fire resistive covering. But many facilities as temporary facilities, parking lot don’t have it. The buckling behavior of steel structures under fire is also significant because it can cause local buckling failure through the reduction in structural material properties by temperature. In this study, the elastic buckling behavior of a circular steel tube under fire was investigated using finite element analysis. The parameters for this analysis used were, diameter–thickness ratio, fire exposure area, and fire scenarios. The elastic buckling strength of circular steel tube rapidly decreased when subjected to the fire curve. Local buckling occurred and this can lead to global failure. When fire resistance design of circular steel tube was performed, buckling behavior must be considered.

Elastic Buckling Behavior of Circular Steel Tube in Fire

화재의 위험이 높은 각종 산업시설 구조물, 물류창고 등 넒 은 공간의 건물은 철골 건물로 건설되고 있다. 이러한 철골구 조물은 고온에서 그 성능이 급격히 저하되어 화재 시 국부 및 전체 좌굴이 발생하여 대형 피해로 이어진다. 대표적으로, 지난 2015년 4월 부산 연제구 중고차 매매단지(부지면적 3166 m 2 )의 화재의 경우 부산소방안전본부에 따르면 차량 560대가 전소되어 약 35억의 재산피해를 가져왔으며 건축물 철거와 감식 작업이 끝났지만 화재 원인은 최종적으로 규명 되지 못했다(Fig. 1). 그러나 Fig. 1과 같이 화재로 인한 차량 의 전소는 내부의 휘발유와 경유로 인하여 일반적인 화재에 비하여 큰 강도의 화재로 이어진다. 본 화재의 경우 철골구조 로 되어 있어 화재가 집중된 중간부분에 원형강관기둥들이 좌굴이 발생함에 따라서 붕괴된 것으로 추정된다. 강재는 온 도에 따라서 급격하게 그 물성치가 변하기 때문에 강구조물 의 내화설계가 매우 중요하다. 강구조물의 경우 항복파괴도 중요하지만 화재에 의한 국부 혹은 전체의 탄성계수 감소에 Abstract

Section performance of submerged floating tunnel using steel composite hollow RC structure

Submerged floating tunnel (SFT) has been considered as an interesting structure to connect the banks separated by a narrow and deep sea. Reinforced concrete (RC) tunnels have been suggested as SFT structures. Because the governing load of a SFT is bending moment, a structure with enhanced stiffness and ductility will be useful for a SFT. Therefore, new-type structures which have superior stiffness and ductility were proposed for the SFT using steel composite Hollow RC member. In this study, the application of steel composite RC structure for SFT was investigated by analysis method. To evaluate the section performance of new type SFT, bending analyses were carried out by using an exclusive program with the considerations of material nonlinearity and confining effect of concrete. Furthermore, module connection for new type SFT was proposed, its performance was evaluated by analysis method.

Damage Rate of Reinforced Concrete Submerged Floating Tunnels Under Fire Scenarios

최근 대륙 간 연결 사업의 추진이 증대되고 있는 가운데 우 리나라 주변에는 한-중 및 한-일 철도 또는 도로 연결에 대한 논의가 진행되고 있다. 이 때 적용 가능한 기술에는 해중터널, 해저터널, 침매터널 등이 있으며, 여기서 해중터널이란 부력 에 의하여 수중에 부유하거나 지지보가 자중을 부담하여 수 중에 잔교식의 형태로 건설되는 터널의 형식을 말하며, 이는 Fig. 1과 같이 일반적인 교량, 침매터널 및 해저터널의 보완구 조물 혹은 대체구조물로 건설 가능하다. Fig. 1은 강 또는 바다를 통해 대륙을 횡단하는 방법을 나타 낸 것으로 1은 일반적인 횡단방법인 교량을 나타내는 것이 고 2는 해중터널 3은 침매터널, 그리고 4는 해저터널을 나 타내고 있다. 일반적인 해중터널의 구조 형태는 부력과 자중 의 관계에 따라 4가지로 나눌 수 있다(Håvard Østlid, 2010). 부력이 자중보다 큰 경우에는 텐션레그 형태의 구조물이 되 Abstract

Behavior Characteristics of Shear Connector for Composite Behavior of Steel Composite Columns

Steel composite structures have been studied in various areas such as bridges, high rise buildings, and wind towers. They show excellent structural performance through overcoming of the weaknesses of steel and concrete. Although various methods were already developed to achieve full composite behavior between steel and concrete in flexural members, the number of studies regarding composite columns is quite limited. If slip occurs between concrete and steel under external loads, the performance of the composite column would be reduced significantly. Connection methods ensuring full composite action between steel and concrete must be suggested. This paper investigated about structural behavior of shear studs through a series of experimental tests. Extensive parameters were also performed to understand the effects of the diameter of stud, space of stud and height of concrete. The present study provides fundamental bases for further development of design method of shear studs in composite columns.

Transverse Reinforcement for Circular Internally Confined Hollow RC column

Recently, bridge structures has progressed the researches about seismic performance by occurrence of earthquake increased compared with the past. In the substructure of bridge, confining transverse reinforcement has arranged in plastic hinge region to resist the lateral load which increased the lateral confining effect. Columns are increased the seismic performance through secure of the stiffness and ductility The design specification for arrangement of confining transverse reinforcement same specification of domestic and international that suggested to solid reinforced concrete column(RC). This design specification have limits for Internally Confined Hollow RC(ICH RC) column because of different the component and performance characteristics of column. In this paper suggested the modified equation for economics and rational design through investigation of displacement ductility when applied the existing specification at the steel composite hollow RC column.