• Journal of Korean Society of Coastal and Ocean Engineers
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• v.3 no.2
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• pp.92-99
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• 1991

A moored body in the sea is subjected to second-order wave forces as well as to linear oscillatory ones. The second-order farces contain slowly-varying components, of which the characteristic frequency can be as low as the natural frequency of horizontal motions of the moored body. As a consequence, the slowly-varying force can excite unexpectedly large horizontal excursion of the body, which may cause a serious damage on the mooring system. In design analysis of Turret-type mooring system which is one of the interesting mooring systems for a floating body. the slowly-varying drift forces and the transient motion of the system during weathervaning are very important. In this paper the slowly-varying drift forces were calculated by using the Quadratic Transfer Function with considering the second order free-wave contributions. Additionaly the transient surge motion of the moored body was simulated with including the roll of the time-memory effect. In this simulation the spring constant of the spread Turret mooring system is updated at every time step for considering the nonlinear effect.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.26 no.4
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• pp.293-300
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• 2013

In this study we proposed a simplified finite element model of anchor bolt system inserted through concrete structures considering clamping forces. The three different finite element types using LS-DYNA are applied for numerical efficiency of the anchor bolt modeling. Combined beam and solid elements are used to reflect the tension state at internal part of anchor bolt due to torques. The clamping forces due to torques are considered by introducing a compression for a nut plane modeled by beam elements. The numerical examples show good agreement with different element types. Parametric studies are focused on the various effects of different element types on the induced axial and shear forces of anchor bolts considering clamping forces.

• Journal of the Korea Concrete Institute
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• v.15 no.2
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• pp.183-196
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• 2003

This paper evaluates the effects of haunches and the characteristic differences of haunch design regulations through design of pier and box structures with/without haunches. The design of the pier and box structures was conducted by using the linear elastic plane stress finite element analysis, the DIN 1045 and ACI 318-99 codes, the suggested experimental design equations, and the strut-tie model approach. To prove the validity of design results obtained by the strut-tie model approach, the ultimate strength of two haunched reinforced concrete beams tested to failure was evaluated by using the approach. According to the comparison and evaluation of the design results, it is concluded that the design results of haunched reinforced concrete structures by using conventional and design codes need to be complemented with those by using the strut-tie model approach that reflected the effects of haunches in design comparatively well through the actions of arch and direct transfer of applied loads.

• International Journal of Highway Engineering
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• v.11 no.4
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• pp.79-85
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• 2009

Dowel-bar in the jointed concrete pavement has been designed and constructed by Foreign standard and experience in Korea. Timoshenko solution was evaluated for dowel bar design. However, various assumptions, Timoshenko solution evaluated only single dowel bar. Therefore, This study object is evaluated the guide line dowel size and arrangement that using the 3Dimensional Finite Element Method. Dowel bar behavior, Timoshenko solution and 3D FEM estimated used result. Dowel allowable stress and Friberg bearing stress estimated using result. The effects of Dowel Group Action were analyzed using Timoshenko range and Friberg range and 3D FEM.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2009.04a
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• pp.55-58
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• 2009

본 논문에서는 독립적으로 구성된 유한요소 모델을 결합하기 위하여 계면에서 불일치 격자들을 처리하는 기법을 소개하고자 한다. 불일치 격자들로 인하여 요소들의 침투와 틈이 발생할 수 있고 일반적인 유한요소를 사용하면 계면에서 변위의 연속성과 하중전달 조건들을 만족시키기가 불가능하게 되는데 계면에서 정의된 계면요소를 사용하여 결합을 위한 조건들을 만족시킬 수 있게 된다. 요소들의 침투와 틈이 없는 연속적인 계면을 정의하고 여기에 부합하는 계면요소를 구성하며 유한요소 형상함수와 다른 계면요소 형상 함수를 사용하게 되면 독립적으로 구성된 분리 영역들을 자연스럽게 결합할 수 있게 된다. 계면요소는 연속성, 적합성, 완전성 등에서 유한요소와 유사한 특성을 갖으며 추가적인 자유도 없이 불일치 격자를 결합하게 된다. 계면요소법을 사용하여 분리된 영역의 결합이나 전체-국부 해석 그리고 유체-구조물 상호작용해석 등에 적용되어 유용한 방법으로 사용될 수 있게 된다.

• Journal of the Korean Geotechnical Society
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• v.25 no.5
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• pp.65-73
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• 2009

Large scale model tests and numerical analyses are performed to investigate the stress distribution of pillar due to surface loading nearby two-arch tunnel which is constructed in the regularly jointed rocks. It is observed that the influence of discontinuities on the stress distribution in the discontinuous rock mass and the underground stresses induced by surface loading are greater than those of linear elastic theory. Especially, lines of equal stresses are developed to the direction of inclination according to the inclined grade. In cases of discontinuities imbedded in parallel with or vertical to the ground, the pressure bulbs are formed symmetrically, however, the inclined ones result in stress distribution in parallel with and vertical to the planes of discontinuities. Results indicated that stress distribution is seriously affected by the angle of discontinuity. When stresses propagating to the pillar need to be estimated, relative location of surface loading, grade of discontinuous plane, and location of two-arch tunnel should be carefully considered.

• Journal of the Korean Geotechnical Society
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• v.23 no.4
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• pp.79-90
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• 2007

Behaviors of instrumented steel sheet piles which are installed in sand ground by vibratory hammer were investigated. Especially, stresses acting on the pile during vibratory driving, efficiency factor which reflects differences between theoretical driving force and actually delivered acting force, justifiability of rigidity of steel sheet pile, dynamic resistance characteristics of soil and penetration characteristics of sheet pile were analysed. According to the field test results it is justifiable that steel sheet pile behaves as a rigid body during vibratory driving. And it can be seen that maximum stress acting on sheet pile section is far less than tensile strength of the material. Value of the maximum section force at sheet pile head was 72% of that estimated from theoretical equation. Magnitudes of displacement amplitudes computed from displacement-time history curve corresponding to four penetration depths were in the range of 16 $\sim$ 75% of that specified by manufacturer.

• Journal of Aerospace System Engineering
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• v.16 no.1
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• pp.97-103
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• 2022

An aircraft component can only be mounted on an aircraft if it has been certified to have a structural robustness under flight load conditions. Among the major components of the aircraft, a pylon is a structure that connects external equipment such as an engine, and external attachments with the main wing of an aircraft and transmits the loads acting on it to the main structure of the aircraft. In civil aircraft, when there is an incident of fire in the engine area, the pylon prevents the fire from spreading to the wings. This study presents the results of structural static tests performed to verify the structural robustness of a fuel pylon used to mount external fuel tank in an aircraft. In the main text, we present the test set-up diagram consisting of test fixture, hydraulic pressure unit, load control system, and data acquisition equipment used in the structure static test of the fuel pylon. In addition, we introduce the software that controls the load actuator, and provide a test profile for each test load condition. As a result of the structural static test, it was found that the load actuator was properly controlled within the allowable error range in each test, and the reliability of the numerical analysis was verified by comparing the numerical analysis results and the strain obtained from the structural test at the main positions of the test specimen. In conclusion, it was proved that the fuel pylon covered in this study has sufficient structural strength for the required load conditions through structural static tests.

• Journal of Korean Society of Steel Construction
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• v.19 no.3
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• pp.303-312
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• 2007

Steel box girder bridges are being commonly designed for medium-span bridges of span length. Composite truss bridges with steel diagonals instead of concrete webs can be an excellent design alternative, because it can reduce the dead weight of superstructures. One of the key issues in the design of composite truss bridges is the joint structureconnecting the diagonal steel members with the upper and lower concrete slabs. Because the connection has to carry concentrated combined loads and the design provisions for the joint are not clear, it is necessary to investigate the load transfer mechanism and the design methods for each limit state. There are various connection details according to the types of diagonal members. In this paper, the joint structure with group stud connectors welded on a gusset plate is used. Push-out tests for the group stud connectors of were performed. The test results showed that the current design codes on the ultimate strength ofthe stud connection can be used when the required minimum spacing of stud connectors is satisfied. Flexure-shear tests were conducted to verify the applicability of the design provisions for combined load effects to the strength of joint structures. To increase the pullout strength of the connection, bent studs were proposed and utilized for the edge studs in the group arrangement of the joint. The results showed that the details of the joint structure were enhanced. Thereafter, design guidelines were proposed.

• Journal of the Korea institute for structural maintenance and inspection
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• v.23 no.1
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• pp.19-26
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• 2019

The masonry infill walls are one of the most popular components that are used for dividing and arranging spaces in building construction. In spite of the fact that the masonry infills have many advantages, the system needs to be used with caution when the earthquake load is to be considered. The infills tend to develop diagonal compression struts during earthquake and increase the demand in surrounding RC frames. If there are openings in the infill walls, the loading path gets even complicated and the engineering judgements are required for designing the system. In this study, a masonry infill system was investigated through finite element analysis (FEA) and the results were compared with the current design standard, ASCE 41. It is noted that the equivalent width of the compression strut estimated by ASCE 41 could be 32% less than that using detailed FEA. The global load resisting capacity was also estimated by 28% less when ASCE 41 was used compare to the FEA case. Rather than using expensive FEA, the adapting ASCE 41 for the analysis and design of the masonry infills with openings would provide a good estimation by about 25% conservatively.