제한된 토지의 효율적 이용을 위하여 건물들이 점점 더 거대화, 초고층화 되어가고 있기 때문에, 대형합성기둥에 대한 수요가 증가하고 있는 추세이다. 선행 연구를 통하여 리브를 갖는 냉간성형강재를 사용하여 구조적으로 안정적이며 경제적 인 충전강관기둥(ACT Column Ⅰ)이 기존에 개발되었으나, ACT Column Ⅰ은 크기가 제한(618×618)되는 문제가 있기 때문에 새로운 폭 1m이상 고하중용 대형합성기둥의 개발이 필요하다. 본 연구에서는 폭이 커지고 접합부 형식이 단순해지는 대형합성기둥(ACT Column Ⅱ)를 제안하고, 바인딩프레임이 보강된 실험체를 중심압축가력하여 구조성능을 확인하였다. 콘크리트 충전 여부 및 바인딩프레임의 보강 폭과 면적을 변수로 한 바인딩프레임 보강 실험체를 중심압축가력 하여 실험체 최대내력 값과 KBC2016 합성구조 설계메뉴얼에 따른 설계내력을 비교한 결과 ACT Column Ⅱ이 대형합성기둥으로써 안정적으로 거동함을 확인하였다.

Composite columns are increasingly used due to the construction of super-tall buildings and large-scale buildings. Studies on the shapes of and construction technologies for structural members using steel tubes are being conducted actively. Welded built-up CFT columns previously developed and commercialized by the authors of this study (ACT-1 columns) are structurally stable and economically efficient. However, the 1m limit in the width of the columns and their small interior spaces impose a difficulty in installing reinforcing materials and thus deteriorate the ease and efficiency with which they are constructed. This study suggests placing thick plates at the centers of the surfaces of the existing ACT-1 column and installing a binding frame (binding frames) at the central thick plates to enhance the integrity and resist lateral pressure caused by concrete casting. Finite element analysis was conducted with the variables of the number and cross-sectional size of the binding frame and the cross-sectional size of the steel tube to estimate the structural behavior of the steel tubes. Hydraulic tests were conducted to analyze load-displacement relations and identify the influence of the binding frames on the relations. The variables in the tests were the number and cross-sectional size of the binding frame, welding details, column joint and the cross-sectional size of the steel tube

Axial force of the bolt is very important for structural stability. To obtain stability of the structure, axial force of the bolt should satisfy the specification and be maintained over the time. Hence, It is important to the axial force of the bolt is measured and it manages. However, measuring of the axial force using sensors is very expensive. Torque method using frequently in the field is difficult to confirm accurately by the torque coefficient change. In this study, measuring of axial force using elastic force of the spring washer was studied. First, the relational formula is drawn about the pressure in which the spring washer model changes to the annular of the plane state. According to the axial force of the bolt, the necessity height of the spring washer is presented and the finite-element analysis model is recommended. The analysis model research, generally, the axial force of high strength bolt is confirmed. It expands to confirmation of the large caliber bolt.