사장교 주탑의 안정성 해석

안주옥,임정열 경희대학교 산학협력기술연구원 1998 산학협력기술연구논문집 Vol.4 No.-

The nonlinearity of a cable-stayed bridge results in the large displacement of main girder due to a long span, the large axial forces reduce the catenary action of cables and the flexural stiffness. Therefore, th static and dynamic behavior of pylon for a cable-stayed bridge plays an important role in determining its safety. This study was performed to find the behavior of pylon of cable-stayed bridge for the first-order analysis considering of axial load only and for the second-order analysis considering of lateral deflection due to axial load. The axial force and moment values of pylon were different from the results of the first-order analysis and second-order analysis according to pylon shape and cross beam stiffness when the pylon was subjected to earthquake and wind loads. In te second-order analysis, comparing the numerical values of the member forces for the dynamic analysis, type 3 and 4(A type_ were relatively more advantageons types than types 1 and 2 (H type). considering the stability for pylon of cable-stayed bridge(whole structural system), types 3 and 4(A type) with pre-bucking of girder were proper types than types 1 and 2(H type) with buckling of pylon.

스트럿-타이 모델에 의한 T형교각 코핑부 해석

안주옥,임태규 경희대학교 산학협력기술연구원 2004 산학협력기술연구논문집 Vol.10 No.2

The purpose of this study is to determine stress and behavior of the coping zone in pier using the structural analysis based on Strut-and-Tie model. In this study, two investigation methods are used. one is the Strut-and-Tie modeling analysis method and the other is the stress analysis of solids method. Results were compared with finite element analysis results program MIDAS. The analysis results of Strut-and-Tie model are similar to finite element analysis results.

아치 구조의 좌굴 해석

안주옥 경희대학교 환경연구소 1993 環境硏究 論文集 Vol.4 No.-

The buckling loads of parabolic, circular, catenary and fixed arches with pinned and fixed were calculated using the subspace iteration procedures. In this study, linearized buckling analysis by using the geometric stiffness in due consideration of the effect of moment was obtaind comparatively good results.

수화열을 고려한 콘크리트 지하차도 적정 시공법 분석

안주옥,김성민,김동련 한국도로학회 2009 한국도로학회논문집 Vol.11 No.2

This paper describes the methods to propose the optimal material properties and construction steps that prevent cracks due to the thermal stresses induced by the hydration heat under the construction of the concrete underpass structures. To achieve the goal of this study, the heat transfer theories were employed and the three-dimensional finite element model of the underpass structure was developed and used for the structural analyses. If the volume of the concrete member that is placed at one time is significantly large,the member is assumed to be the mass concrete and is easy to induce cracks. In order to minimize the cracks during the construction, two different methods can be utilized: one is to arrange the construction steps optimally and the other is to change the materials to reduce the probability of the crack occurrence. In this study, the analyses were performed by considering the changes in material properties with time, the characteristics of the hydration heat generation for cements and admixtures, the volume of the concrete placement at one time, and the environmental conditions. 본 연구에서는 콘크리트 지하차도 시공 시 수화열에 의한 열응력 분포 특성을 분석하여 시공 재료와 시공 과정에 따른 균열 발생 여부를 분석하여 설계 시에 균열을 억제할 수 있는 재료 특성과 시공 단계를 제시하는 방법에 대하여 연구하였다. 이러한 분석을 위해 열전달 이론을 도입하여 지하차도의 3차원 유한요소해석 모델을 개발하여 구조해석을 수행하였다. 1회타설하는 콘크리트 부재의 부피가 지나치게 크면 매스콘크리트가 되기 때문에 수화열에 의한 균열이 발생하기 쉬우며 이러한 균열을 억제할 수 있는 방법으로는 크게 시공 단계를 적절하게 배치하는 것과 또는 이러한 균열을 방지할 수 있도록 재료특성을 바꾸어 시공하는 것으로 구분할 수 있다. 따라서 본 연구에서는 이를 위해 콘크리트 재료 성질의 시간에 따른 변화특성, 시멘트 종류 및 첨가제 유무에 따른 수화열 발생 특성, 시공 단계에 따른 구조물의 크기, 외부 환경조건 등을 고려하여 분석을 수행하였다.

철근 콘크리트 뼈대구조의 최적 설계

안주옥 경희대학교 산학협력기술연구원 1996 산학협력기술연구논문집 Vol.2 No.-

An optimum design section of concrete framed structure based on the Korean Concrete Standard specifications is presented in this study. SUMT algorithm is used for numerical analysis of optimization. The optimum design section is divided framed structure into beam and column sections. As a result of numerical analysis, it was shown comparatively good results of optimum sections within 10 iterations.

반강절 강뼈대구조의 거동해석

안주옥,조삼원 경희대학교 산학협력기술연구원 2004 산학협력기술연구논문집 Vol.10 No.1

As usual, the beam-to-column connection in the structural analysis of steel frame structure is idealized as fully rigid or ideally pinned. However, since the behavior of real beam-to-column connection is intermediate between fully rigid and ideally pinned, the behavior of idealized model may not agree with real behavior. In this study, the fixity factor that Monforton-Wu suggested is used. In order to represent the feature of semi-rigid joint, a numerical analysis program is implemented in the software package MA TLAB as fixity factor is assumed with respect to rotational stiffness for connection types.

사장교의 설계를 위한 최적 지지조건 결정

안주옥,윤영만,An,Zu-Og,Yoon,Young-Man 한국방재학회 2003 한국방재학회논문집 Vol.3 No.4

사장교 설계에서 최적의 지지조건을 결정하기 위해 사장교 전체구조계의 교축방향에 대해서 주형의 지지조건에 따른 활하중, 풍하중과 지진하중에 의한 주형, 주탑단면력 및 케이블력의 변화를 3차원 수치해석을 통해 검토하였다. 교축방향의 적합한 경계조건 도입은 주형의 지지점과 주탑의 기초부의 반력뿐만 아니라 주형의 휨모멘트에서 많은 변화를 유도할 수 있다. 본 수치해석의 예에서, 종방향 탄성계수값은 활하중이 작용 할 경우는 약 100tonf/m/bearing, 지진하중이 작용 할 경우는 약 100tonf/m/bearing 에서 최적의 지지조건임을 알 수 있다. 즉 본 해석대상 교량에서 종방향 탄성계수값이 <TEX>$100{\sim}1000tonf/m/bearing$</TEX> 일 경우의 지지조건에서 최적의 지지조건을 얻었으며, 이 조건에서 주탑의 단면력을 합리적으로 결정할 수 있음을 알 수 있다. A numerical analysis of cable-stayed bridge is conducted to determine optimum longitudinal modulus of elasticity which represents the boundary condition between the tower and main girder. The effect of longitudinal modulus of elasticity is investigated for different loading condition (live load, wind load, seismic load), respectively. There are significant changes in the member forces as variations of longitudinal modulus of elasticity, such as, <TEX>$k_h$</TEX>=e=100tonf/m/bearing (live load), <TEX>$k_h$</TEX>=e=1000tonf/m/bearing (seismic load), However, the wind loads do not affect member forces. The optimum longitudinal modulus of elasticity is determined from considering minimum member forces in the numerical analysis results.

말뚝강성과 지반특성을 고려한 교량의 거동해석

안주옥,윤영만,An. Zu-Og,Yoon. Young-Man 한국방재학회 2001 한국방재학회논문집 Vol.1 No.3

흙의 비선형 변형 특성과 말뚝의 강성을 동시에 고려한 즉, 말뚝과 지반의 상호 거동을 고려한 말뚝 기초 구조의 해석을 수행하였다. 특히 비균질, 비탄성 재료인 철근 콘크리트 말뚝의 단면응력과 균열 발생등의 원인으로 변화되는 말뚝의 휨강성을 구조해석에 적용하였다. 흙의 비선형 특성치는 토질 종류에 따라 흙의 탄성한계를 넘어 항복을 고려한 P-Y curve를 이용한 방법 및 N치에 의한 내부마찰각 산정에 따른 방법으로 얻었다. 본 연구 결과는 말뚝의 강성변화에 의해 교량상부구조의 변위 및 일부단면력이 커짐을 알 수 있었다. 따라서, 최적설계를 위한 정확한 구조해석에서 말뚝의 강성변화에 따른 적합한 구속조건을 고려할 필요가 있음을 알 수 있었다. The objective of this study is to investigate the behavior of superstructure considering several factors such as change of pile rigidity, soil characteristics, and the constraint condition of support. The results of this study are as follows: 1. Pile-rigidity computed by the rotating deformed plane method is continuously varied up to approximately 5D(D=diameter of pile) below the ground level. This result is consistent with the previous study<TEX>$^{(12)}$</TEX>, in which the pile deformation occurs at approximately <TEX>$3{\sim}6$</TEX> times of pile diameter from the ground level. 2. For bridge structure-pile system, analytical results of internal forces and deformations show different values for modified pile rigidity and unchanged pile rigidity. 3. Detaild analysis considering modified pile rigidity is required for the long-span bridge design with structure pile system.

사장교계의 지지조건에 대한 연구

안주옥,윤영만,An, Zu-Og,Yoon, Young-Man 한국방재학회 2002 한국방재학회논문집 Vol.2 No.3

본 논문에서는 사장교 전체구조계의 교축방향에 대해서 주형을 지지하는 방법에 따른 활하중과 지진하중에 의한 주형, 주탑단면력 및 케이블력의 변화를 3차원 수치해석을 통해 검토하였다. 교축방향에 대한 적합한 경계조건의 도입은 주형의 지지점과 주탑의 기초부의 반력뿐만 아니라 주형의 휨모멘트에서 많은 변화를 유도할 수 있다. 수치해석의 예에서, 주형받침의 교축방향 탄성계수값이 약 $1{\times}10^4$tonf/m/bearing인 경계조건과 주형이 주탑부에 고정된 경계조건을 수치해석한 결과, 주탑의 거동은 거의 유사하나, 주탑부의 고정된 경계조건시 크게 발생하는 주형 모멘트를 감소할 수 있는 종방향 탄성계수값(약 $1\{times}10^4$tonf/m/bearing)을 적용하는 것이 최적 지지조건 값이 됨을 알 수 있다. 또한, 주형 지지조건의 종방향 탄성계수값이 $1{\times}10^4$tonf/m/bearing 부근에서 지진하중 재하의 경우 교축방향에 대한 진동 주기가 약 1.4% 더 길어지는 경향을 보인다. The objective of this study is to evaluate elastic modulus of bridge-axis direction for optimum structure system in the cable-stayed bridge design. In numerical example of this study, a slight change in axis direction elastic modulus causes major modifications of the bridge characteristics when it is $1\times10^4$ tonf/m/bearing or less. Therefore, the elastic modulus was set at this lower limit of $1\times10^4$ tonf/m/bearing where the strength of the entire bridge system is still determined by girder strength and the entire system is insensitive to variations in elastic modulus. Besides, cable-stayed bridge with freely supported girders have slightly longer vibration periods in the horizontal direction for earthquake forces.

박스 거더 교량의 격벽 정착부 해석

안주옥,김현삼 경희대학교 산학협력기술연구원 1998 산학협력기술연구논문집 Vol.4 No.-

Because cross-section of Prestressed Concrete Box Girder Bridge is usually a closed section, its transverse, longitudinal flexural rigidity and elastic stability are very high. Hence, the bridge is very safe and stable during construction and use, and frequently used in these days. It can be applied with advantages to 60=70m span and curved bridges that have a lot of torsional moments. The Box Girder Bridge transmits the upper weight to a pier and abutment through diaphragm built inside the box girder, and prevents the section deformation by increasing the cross-section stiffness. But, the diaphragm, which includes geometric and static discontinuity, causes a lot of problems to be accurately analyzed and reasonably designed only with Korean Design Codes. When a prestressed force ia applied directly to a diaphragm, a large tension force is built up opposite side and lower part of anchorage zone, which causes bursting stress. Cracks around the anchorage zone are found because of bursting stress. The bursting stress and the tension around the diaphragm are not considered in the Korean Design Code. Hence, the prestress transferring mechanism, the analysis of End Strut and the stability of Lower Corner, are needed to study. Analysis using Strut-and-Tie Model has been performed to transverse analysis of diaphragm. An accurate structural analysis about the anchorage zone has been performed by a jStrut-and-Tie Model based on Area-AASHTO and CEB-FIP code, and their results has been compared with those of the Korean Design Code. It has been found that the Korean Design Code underestimates the shear strength of concrete.